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1030 Cards in this Set
- Front
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- 3rd side (hint)
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T or F
The intensity is equal to the power divided by the cross sectional area of the beam. |
True
I = P/area |
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Which of the following is incorrect?
A. P = amplitude² B. I = amplitude² C. P = I x area D. I = P x area E. I = P / area |
D
I = P / cross sectional area of the beam |
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T or F
The velocity of ultrasound is indirectly proportional to the square root of the density of the medium. Assume the compressibility does not affect the density. |
True
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T or F
The velocity of the ultrasound is directly proportional to compressibility. Assume the density is unaffected by compressibility. |
False
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T or F
To transfer sound through a medium, the affected molecules move from one end of the medium to the other. |
False
microns only |
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T or F
Ultrasound waves in soft tissue are transverse waves. |
False
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Longitudinal wave
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Wavelength is the distance for the wave to complete one cycle.
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True
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Frequency is the number of cycles passing a given point each second.
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True
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Non specular reflectors have physical dimension that are greater than the wavelength.
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False
smaller |
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The intensity of the US beam is proportional to the square of the acoustic pressure.
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True
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If the thickness of two materials forming the interface is increased,the percentage of the reflected US wave becomes greater.
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False
Reflection, normal incidence and Z (acoustic impedance) |
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For refraction to occur, the velocity of sound must change between one medium and another.
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True
Bending towards (V1>V2) Bending away (V1,V2) |
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The period of the wave is inversely proportional to the wavelength.
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False
reciprocal |
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The unit for Rayl is kg/m2-s.
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True
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The reflection coefficient for intensity is defined as:
Z2+Z1 / Z2-Z1 |
False
-/+ then squared |
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If the velocity of the first medium is greater than the velocity of the second medium, th beam is bent towards the line drawn perpendicular to the interface.
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True
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Absorption is the process that redirects the beam energy.
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False
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heat, mechanical vibration of molecules
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Which artifact is not related to the unexpected reflection of an acoustic wave
A. Multipath B. Comet Tail C. Reverberation D. Lateral Resolution |
D
Lateral resolution relates to beam diameter. |
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T or F
All artifacts are errors in imaging that do not represent the true anatomy of the imaged organ. Therefore, they are undesirable and should be eliminated if possible. |
False
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Which artifact is not affected by the shape and structure of an ultrasound pulse.
A. lateral resolution B. slice thickness C. mirror imaging D. longitudinal resolution |
C
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What type of artifact causes an ultrasound reflection to be placed at an incorrect depth.
A. lateral incertitude B. range ambiguity C. shadowing D. longitudinal resolution |
B
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Which artifact is not related to the unexpected reflection of an acoustic wave
A. Multipath B. Comet Tail C. Reverberation D. Lateral Resolution |
D
Lateral resolution relates to beam diameter. |
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T or F
All artifacts are errors in imaging that do not represent the true anatomy of the imaged organ. Therefore, they are undesirable and should be eliminated if possible. |
False
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Which artifact is not affected by the shape and structure of an ultrasound pulse.
A. lateral resolution B. slice thickness C. mirror imaging D. longitudinal resolution |
C
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What type of artifact causes an ultrasound reflection to be placed at an incorrect depth.
A. lateral incertitude B. range ambiguity C. shadowing D. longitudinal resolution |
B
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If an US pulse travels through a large cyst at a speed of 1.2 mm/us, what happens to the position of
all echoes distal to the cyst. A. they are placed to shallow a location on the image B. they are placed in too deep a location on the image C. They are likely to be placed at a correct depth |
B
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distal structures= deep
D for D |
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What is the most likely cause of ring down artifact.
a. refraction b. inversion c. reabsorption d. resonance |
D
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R for R
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Where do shadowing artifacts appear most commonly on an acoustic scan?
a. distal to a structure with a high impedance b. proximal to a structure with a a low propagation speed c. distal to a structure with a high attenuation |
c
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How is shadowing artifact expressed?
a. placing the structures too deep on the image b. placing structures in improper lateral position c. placing reflections in multiple locations d. reflectors being absent on the image |
d
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Which of the following can produce shadowing
a. refraction b. attenuation c. reflection d. all of the above |
b
attenuation= shadowing |
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Unexpected low attenuation results in which of the artifacts listed below
a. refraction b. attenuation c. enhancement d. shadowing |
c
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When enhancement occurs, where does it appear on the image?
a. in the near field b. distal to a weak attenuator c. in the far field d. proximal to the weak attenuator |
b
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Acoustic focusing of an ultrasound beam may create which artifact?
a. side lobes b. refraction c. speckle d. enhancement |
d
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Primary effect of multipath artifact on an image
a. poor angular resolution b. acoustic speckle c. mild image degradation d. gross horizontal misregistration |
c
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Side lobe artifact is a result of which of the following?
a. sound beams bending b. linear transducer array architecture c. unexpected low acoustic attenuation d. acoustic energy radiating in a direction other than the beam's main axis |
d
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Side lobe artifact usually results in all of the following except
a. hollow structure's appearing "filled-in" on the image b. reflectors appearing in multiple and improper locations on the image c. reflectors not appearing on the image |
c
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Grating lobes are most common with which type of array
a. electronic array b. linear array c. annular array d. mechanical scanners |
b
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T or F
Grating lobes are a result of substantial acoustic energy directed outward from a linear array transducer, but not along the main axis of the beam. |
T
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A technique used to eliminate grating lobes in modern linear array
a. demodulation b. apodization c. subdicing d. none of the above |
c
subdicing- dividing each crystals into smaller pieces |
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T or F
Grating lobes are attributed only to linear array transducers. |
T
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Six distinct equally spaced reflection appear on an image at ever increasing depths.
a. reverberations b. longitudinal resolution artifact c. ring down d. mirror imaging |
a
ring down is increasing separation |
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Reverberations artifact is produced when
a. two masses lie perpendicular to the main axis of the US beam b. two weak reflectors that lie close to each other c. two strong reflectors that lie close to each other d. a single mass of highly reflective material |
c
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lie along the main US beam
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Mirror imaging artifact is created by which of the following?
a. reflection b. refraction c. propagation speed error d. attenuation |
a
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mirror reflects u
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The anatomic structure associated with a mirror image artifact
a. sometimes shallower on the image than in the body b. always deeper on the image than in the body c. sometimes the same depth on the image as in the body d. never deeper on the image than in the body |
b
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Comet tail artifact
a. weak reflectors, closely spaced, low propagations speeds b. strong reflectors, widely spaced, high propagations speeds c. strong reflectors, closely spaced, low propagations speeds d. strong reflectors, closely spaced, high propagation speeds |
d
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What is comet tail artifact's fundamental mechanism of formation?
a. reflection b. rarefraction c. refraction d. redirection |
a
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mirror image and comet tail all reflection related artifacts
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two small cysts are 2.4 mm apart. A line connecting the cyst is perpendicular to the main axis of an US beam. what will determine whether these structures will appear as two distinct images on the systems display?
a. the beam width b. the pulse length c. the PRF |
a
perpendicular to US beam= lateral resolution (LATA) |
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In standard diagnostic imaging instrumentation, which has the higher numerical value
a. lateral resolution b. longitudinal resolution c. neither |
a
LATA= higher numerical value LARD = more smaller value |
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two small cysts are 2.4 mm apart. A line connecting the cyst is perpendicular to the main axis of an US beam. what will determine whether these structures will appear as two distinct images on the systems display?
a. the beam width b. the pulse length c. the PRF |
a
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perpendicular to US beam= lateral resolution (LATA)
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In standard diagnostic imaging instrumentation, which has the higher numerical value
a. lateral resolution b. longitudinal resolution c. neither |
a
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LATA= higher numerical value
LARD = more smaller value |
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two small cysts are 2.4 mm apart. A line connecting the cyst is perpendicular to the main axis of an US beam. what will determine whether these structures will appear as two distinct images on the systems display?
a. the beam width b. the pulse length c. the PRF |
a
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perpendicular to US beam= lateral resolution (LATA)
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In standard diagnostic imaging instrumentation, which has the higher numerical value
a. lateral resolution b. longitudinal resolution c. neither |
a
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LATA= higher numerical value
LARD = more smaller value |
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What is the artifact known as acoustic speckle produced by?
a. accurate display of tiny reflectors b. large reflectors in the medium c. interference of tiny acoustic wavelets d. resonance of particles in the near field |
c
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What is true of acoustic speckle?
a. its effects are mild and it tends to slightly degrade images b. it is a rare artifact that does not occur in real-time imaging c. its effects are not profound d. nothing can be done to correct it |
a
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Television monitors produce _______ images per second.
a. 60 b. 10 c. 30 d. 40 |
c
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How many horizontal lines are used to produce a picture on a television monitor.
a. 525 b. 60 c. 100 d. 256 |
a
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It takes ____ ms to produce a single frame on a TV monitor using the television scan format.
a. 66 b. 33 c. 63 d. 60 e. 30 |
b
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It takes ___ us to write one horizontal line of information on a TV monitor.
a. 100 b. 60 c. 33 d. 63 |
c
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Vector transducer gives a ____ display format.
a. rectangular b. sector c. neither d. both |
b sector with flat top
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Converts voltage pulses from radiofrequency form to video form.
a. Compensation b. Compression c. Detection d. None of the above |
c
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T or F
Filtering widens bandwidth. |
F
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Increasing gain generally produces the same effect as
a. decreasing attenuation b. increasing attenuation c. increasing compression d. increasing rectification |
a
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If gain is reduced by one half with input power unchanged, the output power is _____ to what it was before.
a. equal to b. twice c. one half d. none of the above |
c
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The modes that show one dimensional (depth) real time images are
a. M-mode b. B-mode c. A-mode d. a and b e. a and c f. all of the above |
e
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The mode that shows two-dimensional real-time images is______.
a. M-mode b. A-mode c. B-mode d. None |
c
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Presentation of echo strength in color improves ______ resolution.
a. spatial b. temporal c. contrast d. azimuthal |
c
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What is the artifact known as acoustic speckle produced by?
a.accurate display of tiny reflectors b. large reflectors in the medium c. interference of tiny acoustic wavelets d. resonance of particles in the near field |
c
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What is true of acoustic speckle?
a. its effects are mild and it tends to slightly degrade images b. it is a rare artifact that does not occur in real-time imaging c. its effects are profound d. nothing can be done to correct it. |
a
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What artifact results from an ultrasound beam finite and measurable three-dimensional profile?
a. acoustic speckle b. multipath artifact c. slice artifact d. grating lobe artifact |
c
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How does thickness artifact commonly express itself?
a. improper location of reflectors b. improper brightness of reflectors c. absence of reflectors d. strong linear echoes |
a
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What artifact that results in improper side-by-side positioning of reflectors?
a. multipath b. comet tail c. refraction d. reverberation |
c
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Which of the following is not a potential cause of artifact in diagnostic imaging?
a. operator error b. equipment malfunction c. patient motion d. ultrasound physics e. none of the above |
e
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What is true of artifacts related to depth resolution?
a. too many reflectors displayed on the image b.position reflectors too deep on the image c. too few reflectors are on the image d. position reflectors displayed too shallow on the image |
c
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Axial resolution artifacts are due to which of the following?
a. multiple reflections b. beam width c. attenuation d. pulse length |
d
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Axial resolution= spatial pulse length
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The lateral resolution of 4 ultrasound machines are listed below. Which of the systems would produce the finest quality picture?
a. 2 cm b. 4 mm c. 6 mm d. 8 hm |
b
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smallest value= good resolution
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The upper limit for the SPTA intensity of a focused ultrasound wave where there have been no observed bioeffects?
a. 1 mW/cm2 b. 10 mW/cm2 c. 100mW/cm2 d. 1 W/cm2 |
d
focused= "choose shorter" value unfocused= "longer" value |
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T or F
One reson why focused beams with low intensities are less likely to cause bioeffects is that a focused beam is less efficient in heating a large mass of tissue to a critical temperature. |
T
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T or F
Focused ultrasound are considered less likely to create bioeffects because they will strike fewer gas bubbles that could potentially caviate. |
T
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smaller diameter beam
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Research has indicated that cavitation ______.
a. never occurs b. cannot occur with short pulses c. can be lethal to living things d. effects are purely theoretical |
c
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Many epidemiologic studies of in utero exposure to ultrasound have concentrated on all of the following findings except
a. head circumference b. birth weight c. cancer d. structural abnormalities |
a
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T or F
An ultrasound system with a lower pulse repetition period generally have better temporal resolution than a system with a higher pulse repetition period. |
True
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T or F
The biological effects of ultrasound are thought to be negligible and therefore few investigations have been performed on the subject. |
False
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Which of the following is not considered a potential mechanism for the production of bioeffects from US exposure to the body?
a. temperature elevation b. fractionation c. cavitation d. mechanical trauma |
b
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Which of the following will improve a system's temporal resolution?
a. increased sector angle b. increased line density c. increased PRF d. increased frequency |
c
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Focusing is most effective in which region of an acoustic beam?
a. the very shallow near zone b. the end of the near zone c. very deep in the far zone d. throughout the entire length |
b
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focal zone
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The diameter of a disc shaped, unfocused piezoelectric crystal is 1 cm. What is the best estimate for the minimum lateral resolution of the US system.
a. 1 mm b. 1 cm c. 5 mm d. 5 cm |
c
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Two US systems are identicalexcept for the diameter of the transducer's piezoelectric crystal. Which system has the farthest focus?
a. the system with a smaller diameter crystal b. their foci will be at the same depth c. the one with a larger diameter crystal |
c
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Two US systems are identical except for the frequency of the emitted pulse. Which system will have the farther focus?
a. the higher frequency system b. the lower frequency system c. both foci will be at the same depth |
a
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Two ultrasound system are identical except for the PRP of the emitted pulse/ Which system will have the farthest focus?
a. the system with lower PRP b. the system with higher PRP c. their foci will be at the same depth |
c
PRP has nothing to do with focus |
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T or F
An US system with a longer PD will generally have better temporal resolution. |
False
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PRP and PRF affects temporal resolution
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T or F
When using an instrument typical of today's imaging devices, a higher frequency transducer is likely to improve the system's transverse resolution. |
True
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LATA
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T or F
When using an instrument typical of standard ultrasonic imaging instrumentation, the lateral resolution has higher value than the axial resolution. |
True
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lateral= bigger values than longitudinal resolution
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T or F
When using an instrument typical of today's imaging devices, a higher frequency transducer is likely to improve the system's range resolution. |
True
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LARD
SPL/2 |
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What will lower the value of an US system's lateral resolution?
a. send the pulse through an acoustic lens b. decrease number of cycles in the pulse c. increase the effective damping material d. increase the PRP |
a
external focusing technique |
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T or F
The shorter the pulse length the better the picture quality. |
T
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One way that a sonographer can alter the system's axial resolution achieved during an exam is to adjust the maximum imaging depth.
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False
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select different transducer
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T or F
The shorter the pulse duration the better the picture. |
True
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T or F
The length of the pulse does not directly influence the temporal resolution. |
True
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T or F
With a specific US system and transducer,the system's range resolution is invariant, and therfore the sonographer can do nothing to improve it. |
True
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LARD determined by the US electronics; cannot be changed by the sonographer
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The lateral resolution of the US system is primarily determined by the _______.
a. width of the sound pulse b. length of the sound pulse c. duration of the sound pulse d. none of the above |
a
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LATA app. equal to the beam width
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The focus of an ultrasound beam is the location where the
a. finest depth resolution is obtained b. beam is the broadest c. optimum traverse resolution is found d. frequency is the highest |
c
focus = most narrow |
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T or F
Focusing is generally ineffective in the far zone. |
True
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An US pulse has a PRP of 1.2 msec, a spatial pulse length of 2.0 and a wavelength of 0.4 mm. What is the radial resolution of the system?
a. 2.0 mm b. 0.4 mm c. 1.0 mm d. 1.8 mm |
c
SPL/2 = LARD |
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A sonographer is performing a study on a patient and desires superior depth resolution. Which of the following changes would create such a system?
a. higher frequency b. shorter wavelengths c. fewer cycles per pulse d. all of the above |
d
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T or F
The lower the numerical value of the longitudinal resolution, the worse the picture produced by the US system. |
False
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smaller-=better
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The more cycles there are in a pulse, the greater the detail that will be visualized in the ultrasound scan.
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False
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higher value= not good image quality
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T or F
The pulse duration does not profoundly influence the lateral resolution. |
True
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T or F
The higher the frequency of the cycles within a pulse; the lower the value of the axial resolution. |
True
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higher frequency= lower wavelength= lower SPL = lower value LARD
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An acoustic pulse reflects from a boundary where the irregularities on the surface of the boundary are much smaller the the pulse wavelength. What type of reflection is most likely to occur under these circumstances?
a. partial b. specular c. Rayleigh d. total |
b
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Two US systems produce acoustic pulses. One pulse is 0.4 usec in duration while the other is 0.2 usec. Which pulse will most likely provide best azimuthal resolution?
a. 0.4 usec pulse b. 0.2 usec pulse c. they are the same d. cannot be determined |
D
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PD has nothing to do with LATA
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Two US systems produce acoustic pulses. One pulse is 0.4 usec long while the other is 0.2 usec long. Which pulse will most likely provide best temporal resolution?
a. 0.4 usec pulse b. 0.2 usec pulse c. they are the same d. cannot be determined |
D
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PD does not affect temporal resolution (frame rate)
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Two US systems produce acoustic pulses. One pulse is 0.4 usec in duration while the other is 0.2 usec. Which pulse will most likely provide best radial resolution?
a. 0.4 usec pulse b. 0.2 usec pulse c. they are the same d. cannot be determined |
B
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Pulse duration (length of pulse) shorter time= shorter PL , lower value
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The radial resolution of an US system is 0.85 mm at the beam's focus. What is the closest estimate of the system's radial resolution that is 5 cm deeper than the focus?
a. equal to 0.85 mm b. less than 0.85 mm c. greater thab 0.85 mm |
a
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LARD determined by SPL (not affected by focusing)
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Pulse Length is (directly or inversely) related to pulse duration.
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Directly
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Q-factor is (directly or inversely) related to bandwidth.
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inversely
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Pulse duration is (directly or inversely) related to bandwidth.
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inversely
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All of the following describes an imaging transducer, except
a. high sensitivity b. low Q c. wide bandwidth d. damped |
a
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The sensitivity of transducers that create short duration pulses is likely to be (greater than, less than, or equal to) that of transducer that create long pulses(non-imaging).
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Less than
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Which of the following is true of all waves
a. they travel through a medium b. all carry energy from one site to another c. their amplitudes do not change d. they travel in a straight line |
b
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As sound travels through a medium, what term describes the effects of the medium on the sound wave
a. toxic effects b. acoustic propagation properties c. bioeffects d. transmission properties |
b
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Waves that exist at the same location and time will combine together. What is this called?
a. inference b. rarefraction c. interference d. longitudinal interaction |
c
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With standard ultrasonic imaging, what happens to the period of a wave as it propagates?
a. increases b. decreases c. remains the same |
c
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Ultrasound is defined as a sound with a frequency of ______.
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d
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Infrasound is defined as a sound with a frequency of _______.
a. greater than 20,000 kHz b. less than 20 Hz c. greater than 10 MHz d. greater than 0.02 MHz |
b
below audible frequency 20 Hz to 20kHz |
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Which of the following are acceptable units for the amplitude of an acoustic wave?
( more than one answer may be corrrect) a. cm b. atmosphere c. gauss d. watts |
A and B
units of acoustic variables |
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The maximum value of the density of an acoustic wave is 60 lb/in2 while the minimum density is 20 lb/in2. What is the amplitude of the wave?
a. 20 lb/in2 b. 40 lb/in2 c. 60 lb/in2 d. none of the above |
a
max-min/ 2 |
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The power of an ultrasound wave can be reported with which of the following units?
(more than one answer may be correct) a. watts/square cm b. dB/cm c. watts d. kg/cm2 |
c
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The final amplitude of an acoustic wave is reduced to one half of its original value. The final power is ____ the original power.
a. the same as b. one half c. double d. none of the above |
d
(1/4) |
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The intensity of an ultrasound beam is defined as the _____ in a beam ____ by the ___ of the beam.
a. power, multiplied, diameter b. amplitude, divided, area c. power, divided, area d. amplitude, multiplied, circumference |
c
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Two saound waves with frequencies at 5 and 3 MHz, travel to a depth of 8 cm in a medium and then reflected back to the body. Which acoustic wave arrives first at the surface of the body?
a. the 5 MHz wave b. the 3 MHz wave c. neither d. cannot be determined |
c
same media |
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Using a specific transducer, what happens to the spatial pulse length as the sonographer increases the maximum imaging depth?
a. increases b. decreases c. remains the same d. cannot be determined |
c
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What happens to the pulse repetition period if the sonographer decreases the maximum imaging depth achieved in an ultrasound scan?
a. increases b. decreases c. remains the same d. cannot be determined |
b
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What happens to the pulse duration when a sonographer decreases the maximum imaging depth in a ultrasound scan?
a. increases b. decreases c. remains the same d. cannot be determine |
c
PD has nothing to do with depth of view |
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The pulse repetition frequency of ultrasound produced by a transducer typical of diagnostic imaging systems ______.
a. can be changed by the sonographer b. depends on the medium through which the sound travels c. is unchanged as long as the same ultrasound system is used d. has nothing to do with clinical imaging |
a
if depth of view is changed |
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In diagnostic imaging, what establishes the PRF?
a. the source of the sound b. the medium through which the sound travels c. both a and b d. neither a nor b |
a
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A sonographer adjusts the maximum imaging depth of an ultrasound system. Which of the following also changes?
a. pulse repetition period b. wavelength c. pulse repetition frequency d. frequency e. more than one of the above |
e
a and c |
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While using a particular imaging system, what happens
to the duty factor when the depth of view increases? a. increases b. decreases c. unchanged |
b
DF is inversely related to depth, this is due to the PRP that increases with depth with constant PD |
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T or F
The sonographer alters the duty cycle when adjusting the maximum imaging depth of a scan. |
True
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While using the same ultrasound machine and transducer, which of the following can a sonographer alter? (more than one answer may be correct)
a. pulse repetition period b. PRF c. frequency d. duty cycle e. pulse duration |
a, b, d
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With continuous wave sound beam, which of the following 4 intensities are the same?
1. SPTA 2. SAPA 3. SATA 4. Im a. 1 and 2 b. 1 and 3 c. 1 and 4 d. 2 and 3 |
d
all temporal and pulse parameters identical |
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Two acoustic beams have identical SPTP intensities of 400 mW/cm2. One beam is pulsed while the other is continuous wave. Which beam has the higher SPTA intensity?
a. the pulsed beam b, the continuous wave c. neither d. cannot be determined |
b
Longer receiving time for PW reduces the SPTA. |
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The scale associated with the decibel notation is _______.
a. linear b. discrete c. logarithmic d. additive |
c
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What units are used to describe attenutation?
a. watts b. watts/cm2 c. macro d. decibels |
d
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To which of the following is Rayleigh scattering related?
a. half of the wavelength b. square root of propagation speed c. frequency^4 d. PRF^2 |
C
ex if frequency 2^4 = 16-fold Rayleigh scattering |
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A sound beam travels 9 cm in soft tissue. The attenuation coefficient is 3 dB/cm. What is the total attenuation that the sound beam experienced?
a. 8 dB b. 3 dB c. 27 dB d. 18 dB |
c
Atten = path length x atten coefficient |
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Half value layer depends upon which of these features?
a. path length and frequency b. path length and propagation speed c. medium and frequency d. PRF and medium |
c
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Sound traveling through blood attenuates to a _____ extend tha when traveling through soft tissue.
a. greater b. lesser c. relatively equal |
b
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Which of these lists indicates media with increasing attenuation of ultrasound?
a. water, lung, soft tissue, bone, air b. lung, air, soft tissue, bone c. lung, fat muscle d. water, blood, fat, muscle, bone, air |
d
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The angle between the direction of propgation and boundary between two media is 90 degrees. What term describes the form of incidence of the wave?
a. not normal b. direct c. oblique d. orthogonal |
d
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Which term does not belong to the group below?
a. orthogonal b. at right angles c. oblique d. 90 degrees e. normal f. perpendicular |
c
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A sound wave strikes a boundary between two media at 60 degrees angle. This is called ________ incidence?
a. orthogonal b. angular c. obtuse d. oblique |
d
not normal( 90 degree angle) is oblique |
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Which term has a meaning other than normal incidence?
a. orthogonal incidence b. perpendicular incidence c. oblique incidence |
c
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A sound pulse strikes a boundary between two media with normal incidence. The speed of sound in the two media are very different; however, the impedances of the media are identical. What will happen?
a. a big echo will be produced b. a medium echo will result c. a small echo will result d. there will be no echo at all |
d
same impedance= no reflection 100% of sound will be transmitted |
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An ultrasound wave approaches an interface between two media at a 90 degree angle. The propagation speeds and the densities of the two media are different. What is corrrect?
a. reflection will definitely occur b. reflection will definitely not occur c. refraction may occur d. none of the above |
d
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An ultrasound wave strikes a boundary between two media. All intensities are measured directly at the boundary. What results when the transmitted intensity is divided by the reflected intensity?
a. intensity reflection coefficient b. intensity transmission coefficient c. beam uniformity coefficient d. none of the above |
d
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Which of the following best describes the process described by Snell's Law?
a. reflection with normal incidence b. reflection with oblique incidence c. transmission with normal incidence d, transmission with oblique incidence |
d
Refraction is "transmission with a bend" |
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T or F
Refraction always occurs at the interface between two media when the propagation speeds of the media are unequal? |
F
1. oblique incidence 2. propagation speed |
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All of the fowlloiwng terms describe the shape of a sound wave created by a tiny fragment of PZT except:
a. spherical b. Huygen's wavelet c. V-shaped d. hourglass shaped |
d
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T or F
When using standard ultrasonic imaging instrumentation, the lateral resolution has a higher numerical value than the axial resolution. |
T
axial is better than lateral |
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Which of the following term means adjustable focusing or multi-focusing?
a. dynamic aperture b. harmonics c. frequency agility d. phased array |
d
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When looking at images prodeuced by these transducer systems, which one can be distinguished from all the others?
a. linear phased array b. linear switched array c. annular phased array d. mechanical transducer |
b
rectangular shaped |
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T or F
All phased array transducer systems direct ultrasound pulses in many directions to create a 2 dimensional image. |
T
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What is true of the electrical pulses that excite the active elements of an annular phased array transducer?
a. they arrive at each PZT crystal at exactly the same timne b. they vary in amplitude based on the direction of the steering and focusing c. they excite the crystals at different times, nanoseconds apart d. they arrive at each PZT crystal at different times, microseconds apart |
d
angular transducer= microseconds apart linear phased = nanoseconds |
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How are the PZT crystals excited when using an US system with a sequential array transducer?
a. singly and in order; first, second, third... b. in pairs, the first 2 crystals, the 2nd, the 3rd.... c. in a specific order d. in a random sequence |
c
determined by the manufacturer |
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How are the PZT crystals of a linear phased array transducer fired?
a. in a single, specific pattern b. in order from top to bottom c. at exactly the same time d. at almost exactly the same time |
d
nano seconds interval |
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Which of the following forms of focusing different than the others?
a. lens b. mirror c. phased d. dynamic receive |
d
during reception of signals, the rest is during transmission |
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T or F
A half-value layer is the amount of material required to reduce the intensity of the beam by a factor of 2. |
True
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T or F
Absorption is the only process that redirects the ultrasonic beam. |
False
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reflection, refraction, scattering, divergence, absorption
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If an ultrasonic beam is directed at an interface a a 20 degree angle of incidence and the velocity of of medium No. 1 is greater than that of medium No. 2, the beam will bent towards the normal incidence.
|
True
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V2 > V1 , the beam will bent away from the normal incidence
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The distance of a tissue interface is 2 cm from the face of the transducer. How much time elapses between the transmitted ultrasonic pulse to the detected echo.
A. 13 us B. 26 us C. 130 us D. 260 us |
B
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1 cm, 13 us
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How far away is an interface in tissue if the elapsed time for the sound wave to travel out and back is 260 us?
A. 20 mm B. 40 cm C. 40 mm D. 20 cm |
D
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As the thickness of the two materials forming the interface is increased, the magnitude in percentage of the reflected echoes ___________.
A. Becomes smaller B. Remains unchanged C. Becomes smaller |
B
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Thickness won't affect reflection; it's the acoustic impedance difference.
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The percentage of reflection at an interface between two media having different acoustic impedances will ______ when moving across the low impedance medium to the high impedance medium.
A. Increase B. Decrease C. Remains the same |
C
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Reflection is related to angle of incidence not to acoustic impedance.
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If the level of intensity is decreased by a factor of 2, this corresponds to a reduction of ____________.
A. -6 dB B. -3 dB C. -12 dB D. -9 dB |
B
|
reduced to factor of 2 = -3 dB
factor of 4 = -6 dB factor of 8 = -9 dB factor of 10= -10dB + dB ( final intensity is bigger than the original intensity) |
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If the frequency of a new transducer is twice that of the old one, the newer one will exhibit ______ times the
wavelength of the older one and _______ times the attenuation of the older one. A. 1/2, 2 B. 1/2, 1/2 C. 2,2 D. 2, 1/2 |
A
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wavelength vs frequency
frequency = attenuation |
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Refraction does not occur under the conditions_________.
A. Normal incidence B. V1 = V2 C. Z1 = Z2 D. A and B E. A and C |
D
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Specular scattering occur when the interface is ____ the width of the ultrasound beam and non specular reflections occur when the interface is ____ the width of the ultrasound beam.
A. The same as, larger than B. Smaller than, larger than C. Larger than, smaller than |
C
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nonspecular
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scattering (RBC)
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Rayleigh scatter also
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Longitudinal wave
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ultrasound
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interference
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algebraic summation of waves
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Constructive
Destructive, Complete destructive |
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Rayl is a unit of _____.
|
acoustic impedance
MKS system |
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The ability of the system to image small targets at a given depth
a. resolution b. sensitivity c. bit/pixel d. none of the above |
b
Sensitivity |
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The speed at which sound moves through a medium
|
Velocity
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The SATP intensity is 1 mW/cm, the duty factor is 1.2 msec, and the SP/Sa factor is 5 percent.
1.Which paprameters have incorrect units 2. Is this a pulsed or continuous system |
1. SATP = mW/cm2
Duty factor = unitless (0-1) SP/SA factor unitless min is 1, maximum >1 2. Cannot tell CW, Duty factor = 1.0 |
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Which of the following is the lowest intensity.
A. SATA B. SPTA C. SPTP D. SATP |
A
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SPTP
SATP SPTA SATA |
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What parameters is/are the same in pulse and continuous system
A. SPTP and SPTA B. SATP and SATA C Both D Neither |
C
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Two-dimensional ultrasound imaging is performed with either static B-mode gray-scale units or _______.
A. Real- time scanning B. Color flow Doppler imaging C. Both |
A
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T or F
Real time imaging have totally replaced static imaging. |
False
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almost
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T or F
To build up a 2D image, the transducer is manually moved by the sonographer to a different orientation to acquire information along a new line of sight. |
True
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PRF decreased if
A. scanning depth is increased B. velocity is decreased C. number of lines of sight is increased D. All of the above |
D
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FR = c / 2DN
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Increased number of lines per sight increased spatial resolution.
|
True
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Registration arm and scan converter is not necessary in real time imaging.
|
True
Freeze frame , scan converter is needed. |
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Types of real time scanners
A. Mechanical B. Electronic Linear Array C. Electronic Phased Array D. All of the above |
D
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True with mechanical real-time scanner; except.
A. Simplest and least expensive B. Mechanical motion of crystals to acquire lines of sight C. Uses only one crystal D. Uses contact or liquid path scanner E. have dynamic focusing |
E
fixed, mechanical focusing |
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The vibrating sector scanner uses a motor which wobbled back and forth during data collection while the other type of mechanical scanner uses ______.
A. Rotating wheel B. Oscillating wheel C. Wobbling wheel D. None of the above |
A
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Oscillating or wheel contact scanner produce a ____ shaped format.
A. Rectangular B. Blunted C. Sector- shaped D. All of the above |
C
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or pie shaped format
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Components of a continuous wave unit; except
A. Oscillator B. RF amplifier C. Demodulator D. Audio amplifier E. None of the above |
E
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Continuous wave Doppler imaging can provide the following information; except
A. Duration B. Depth C. Amplitude D. Direction |
B
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Maximum Doppler velocity in PW
A. As the depth of interest is increased the reflector velocity decreased B. Low frequency transducer allows greater velocities to be detected C. Both D. None of the above |
C
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Nyquist limit
A. sampling rate must be at least twice the maximum frequency B. One half of the PRF C. Both D. Neither |
C
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T or F
Aliasing is present in both PW and CW. |
False
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To remove aliasing artifact
A. Increasing the PRF B. Adjusting the baseline C. Lowering the transducer frequency D. Increasing the Doppler angle E. All of the above |
E
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T or F
Decreasing the bandwidth by lengthening the pulse improves the systems ability to detect weak Doppler shifts. |
True
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Techniques to identify a positive or negative shift
A. Single sideband B. Heterodyne C. Quadrature phase detection D. All of the above |
D
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Most commonly used directional technique in PW
A. Single side-band B. Quadrature phase detector C. Heterodyne D. None of the above |
B
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A technique applied after quadrature phase detection to generate two separate output signal
A. Reference signal processing B. Frequency domain processing C. RF amplification D. Offset signal processing |
B
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Static color flow imaging
A. May operate in PW B. May operate in CW C. Both D. None of the above |
C
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Combine real-time imaging with CW or PW Doppler detection.
A. Duplex scanners B. Static color flow Doppler C. Spectral Doppler D. All of the above |
A
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Duplex scanner
A. Real time image depicts stationary reflectors B. Doppler mode provide flow information C. Both D. None of the above |
C
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Anatomic structures aids in the selection of line of sight for CW Doppler or ____ for PW Doppler.
A. Gate B. Filter C. Depth D. Sample volume |
D
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Disadvantages of static color flow imaging; except
A. neigboring stationary structures are displayed B. short scanning time for two dimensional mapping C. Both D. Neither |
D
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Analysis of Doppler signal
A. Fast Fourier Transform B. Parallel filter bank C. Time compression D. All of the above |
D
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Is the process of separating a wave form into series of single-frequency sine-wave components.
A. Parallel filter bank B. Time compression C. Fast Fourier Transform D. None of the above |
C
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T or F
Power spectrum displays a plot of magnitude of individual frequency components versus frequency that converts the complex Doppler signal from time domain into the frequency domain. |
T
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Characterized by blood moving at a single velocity.
A. Blood flow B. Plug flow C. Vessel flow D. Laminar flow |
B
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Stenosis has
A. Turbulent flow B. Slowly moving elements C. Presence of eddies D. all of the above |
D
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T or F
A uniform beam intensity that encompasses the entire vessel (beam shape) results to a more accurate laminar flow power spectrum. |
T
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Power spectrum consists of
A. Magnitude B. Frequency C. Time D. All of the above |
D
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Brightness in the power spectrum corresponds to
A. Time B. Frequency C. Magnitude D. Velocity |
C
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A rapid Fast Fourier Transform processing of the power spectra in real time displays
A. Vertical axis=frequency B. Horizontal axis= time C. Brightness = amplitude D. All of the above |
D
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Power spectra artifacts
A. Mirror image B. Aliasing C. Wrap-around D. Weak signals detected with high gain settings E. A nd B F. All of the above |
F
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T or F
Transit time broadening is a limitation of the FFT processing. |
T
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Features of disturbed flow
A. Increased peak velocity B. Spectral broadening C. Altered flow direction D. Less pulsatile shape E. All of the above |
E
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Descriptors of power spectrum
A. Maximum frequency B. Mean frequency C. Median frequency D. Mode frequency E. All of the above |
E
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T or F
Mean frequency corresponds to the fastest moving RBCs within the sample volume at the time of measurement. |
F
|
Max f
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T or F
Mean frequency is calculated from weighted sum of frequencies in the power spectrum. |
T
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An example of a non specular reflector is
a. the liver surface b. the diaphragm c. red blood cells d. any structure that does not produce a strong echo |
c
Diffuse reflectors/ Structures smaller than the wavelength will scatter sound in all directions |
|
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The spatial pulse length
a. determines the penetration depth b. usually decreases with increased frequency c. is improved with rectification d. determines the lateral resolution |
b
SPL = # of cycle x wavelength Wavelength and freq inversely proportional |
|
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|
Axial resolution
a. is improved in the focal zone b. depends on the TGC slope c. is improved by digital scan converters d. depends on the wavelength |
d
LARD= determined by wavelength, damping and freq |
|
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Lateral Resolution
a. and ring-down are the same b. depends on the beam diameter c. improves with frequency d. cannot be measured in the far zone |
b
LATA = defined as equal to beam diameter |
|
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The beam of an unfocused transducer diverges
a. because of inadequate damping b. in the Fresnel zone c. in the Fraunhofer zone d. when the pulse length is long |
c
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Reverberation artifacts are a result of
a. electronic noise b. improper TGC settings c. the presence of two or more strong reflecting surfaces d. an angle of incidence that is too small |
c
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|
Grating lobes are essential for the proper operation of a linear phase array.
a. True b. False |
B
Grating lobes are undesirable property of multi element transducer |
|
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|
Electronically steered scanners always produce higher resolution images than do mechanical steered scanners
a. true b. false |
b
resolution is a function of focusing |
|
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An annular array scanner uses mechanical beam steering
a. true b. false |
a
annular array cannot be electronically steered |
|
|
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A linear sequenced array cannot be dynamically focused
a. true b. false |
b
controlled by timing for focusing |
|
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Decreasing the SPL
a. reduces the field of view b. reduces lateral resolution c. improves axial resolution d. improves lateral resolution |
c
Axial resolution= 1/2 SPL |
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How much will a 3.5 MHz pulse will be attenuated after passing through 2 cm fo soft tissue
a. 7 dB b. 3.5 dB c. 17 dB d. 1.75 dB |
b
attenuation = atten coeff x path length Atten coeff= freq/2 |
|
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|
Propagation speed errors result in
a. reverberation b. improper axial resolution c. shadowing d. a Doppler shift |
b
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Enhancement is caused by
a. strong reflecting structures b. propagation speed errors c. Snell's law d. weakly attenuating structures |
d
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|
The Doppler shift frequency is
a.directly proportional to the velocity of the reflector b. greater in pulsed Doppler system c. greater at high intensity levels d. dependent on the number of transducer elements being used |
a
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|
|
The number of frames per second necessary for a real-time image to be flicker free is
a. more than 15 b. less than 10 c. between 6 and 10 d. between 3 and 6 |
a
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|
|
The dynamic range of a system
a. is increased when specular reflectors are scanned b. is decreased when shadowing is present c. can be increased through the use of coupling gel d. is the ratio of the smallest to largest power level that the system can handle |
d
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|
|
T or F
The intensity of an ultrasonic beam can be measured with radiation force balance |
T
Radiation pressure can be measured with a sensitive balance and converted to intensity |
|
|
|
Increasing the PRP
a. improves lateral resolution b. increased the maximum depth that can be imaged c. decreased the maximum depth that can be imaged d. increases refraction |
b
Trade-off bet frq and wavelength |
|
|
|
T or F
No refraction can occur at an interface if the media impedances are equal |
F
Refraction= prop speed in medium Reflection and transmission= Z |
|
|
|
T or F
The SPTA instensity will always be larger than the SATA intensity |
T
SPTP>SATP>SPTA>SATA |
|
|
|
The intensity of the ultrasound beam is usually greater at the focal zone because of
a. decreased attenuation b. smaller beam diameter c. diffraction effects d. shorter duty factor |
b
beam area decreases, intensity increases |
|
|
|
If the amplitude is doubled, the intensity is
a. doubled b. increased by four times c. cut in half d. unchanged |
b
I = Amplitude2 |
|
|
|
The attenuation for soft tissue is
a. increased with tissue thickness b. determined by the slope of the TGC curve c. increased with decreasing wavelength d. unimportant when using digital scan converters |
a
Path length |
|
|
|
The acoustic impedance of the matching layer
a. can be chosen to improve transmission into the body b. must be larger than the transducer material to reduce attenuation c. is not necessary with real-time scanner d. must be made with the same material as the damping material |
a
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|
|
T or F
The pulsed-echo system, the Q factor should be made as large as possible |
False
Length of time that the sound persist Low Q = low SPL= good LARD |
|
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T or F
The beam diameter is constant in the near zone |
False
(waist) |
|
|
|
The operating frequency
a. depends on the transducer ring-down time b. depends on the thickness of the crystal c. is increased as the crystal diameter is decreased d. depends on the strength of the pulser |
b
|
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|
|
The period of an ultrasound wave is
a. the time at which it is no longer detectable b. determined by the duty factor c. the time of one wavelength d. independent of the frequency |
c
|
|
|
|
T or F
Smaller transducers always produce smaller beam diameter |
F
beam diameter depends on whether the beam is focused, distance from the transducer, Near field or far field |
|
|
|
T or F
The ultrasound beam profile can be measured with a hydrophone |
True
|
|
|
|
T or F
The pulsed- Doppler system yields better depth resolution than the continuous wave system. |
T
|
|
|
|
T or F
The gray-scale display was made possible with digital scan converters replaced analog scan converters. |
False
|
|
|
|
T or F
Videotape recorders operating at 30 frames per second cannot be used with mechanical real-time units because the frame rate is too slow |
False
depends on imaging rate |
|
|
|
T or F
Linear phased array scanners need no form of mechanical focusing since focusing is performed electronically |
F
|
|
|
|
T or F
The frame rate of real-time scanners depends on the number of lines used to form one image |
T
|
|
|
|
T or F
It is not possible to steer an annular phased array electronically. |
T
|
|
|
|
T or F
The near zone length should be kept as short as possible |
F
|
|
|
|
What percentage of intensity of an ultrasound pulse incident on an interface of 0.25 and 0.75 rayls is reflected.
|
C
(Z2-Z1/Z2+Z1) squared |
|
|
|
Axial resolution can be improved by using
a. higher frequency transducer b. lower frequency transducer c. larger transducer d. poorly damped transducer |
A
|
|
|
|
When particle of motion of a medium is parallel to the direction of a wave propagation, the wave being transmitted is called a
a. longitudinal wave b. shear wave c. surface wave d. lamb wave |
a
|
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|
|
The wavelength in a material having a wave velocity of 1500 m/s employing a transducer frequency of 5 MHz is
a. 0.3 mm b. 0.3 cm c. 0.6 mm |
a
wavelength = c/ f |
|
|
|
The factor that determines the amount of reflection at the interface of two dissimilar materials is
a. index of refraction b. the frequency of the ultrasonic wave c. Young's modulus d. the specific acoustic impedance |
d
|
|
|
|
The equation that describes the relationship among propagation, wavelength and frequency.
a. v= f x wavelength b. wavelength = 2 (frequency x velocity) c. Z = p V d. Wavelength = freq + velocity |
A
|
|
|
|
Which of the following can occur when an ultrasound beam reaches the interface of 2 dissimilar materials
a. reflection b. refraction c. mode conversion d. all of the above |
d
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|
|
|
The acoustic impedance of a material is
a. directly proportional to the density and inversely proportional to velocity b. directly proportional to velocity and inversely proportional to density c. inversely proportional to density and velocity d. equal to the product of density and velocity |
D
|
|
|
|
The average velocity of ultrasonic waves in soft tissue is
a. 1540 ft/s b. 3330 m/s c. 1540 m/s d. 300 x 10^6 m/s |
c
|
|
|
|
T or F
Receiver-angle values in CW Doppler analysis do not influence the final Doppler shift |
F
directly related to cosine of the angle |
|
|
|
Refraction occurs due to difference in ___ across an interface between two materials.
a. acoustic impedance b. wave velocity c. density d. none of the above |
b
Difference in prop speed |
|
|
|
Reflection factor at an interface between two materials depends primarily on the change in ____ acrosss the interface.
a. acoustic impedance b. wave velocity c. density d. all of the above |
a
|
|
|
|
The velocity of sound waves is primarily dependent on
a. angulation b. reflection c. the material through which the sound is being transmitted and the mode of vibration d. none of the above |
c
|
|
|
|
Increasing the frequency of an ultrasonic longitudinal wave will result in _____ in the velocity of that wave.
a. an increase b. a decrease c. no change d. a reversal |
c
velocity is dependent on the medium through which it travel |
|
|
|
The change in the direction of an ultrasonic beam, when it passes from one medium to another, in which elasticity and density differ from those of the first medium is called
a. refraction b. rarefraction c. angulation d. reflection |
a
Snells Law |
|
|
|
A long near zone can be obtained by
a. using a high frequency transducer b. adding a convex lens to the transducer c. decreasing the diameter of the transducer d. increasing the damping |
a
x = r^2/ wavelength r= transducer diameter wavelength and freq relationship |
|
|
|
If a 2-MHz frequency is used in human soft tissue, the wavelength is approximately
a. 0.75 mm b. 0.15 mm c. 0.21 mm d 0.44 mm |
a
1.50 mm/us / 2 MHz |
|
|
|
The ratio of particle pressure to particle velocity at a given point within the ultrasonic field is
a. interference b. impedance c. incidence d. noise |
b
Z= particle pressure/ particle velocity |
|
|
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What is the following formula used to determine
2 x velocity x orig freq / velocity of sound a. shift in frequency due ot Doppler effect b. degree of attenuation c. distance a wave front travels d. amount of amplification necessary to produce diagnostic ultrasound |
a
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The principle which states that all point on a wave front can be considered as a point sources for the production of spherical secondary wavelets was postulated by
a. Doppler b. Young c. Huygen's d. Langevin |
c
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A 10-dB difference in signal intensity is equivalent to a ___ difference
a. twofold b. tenfold c. hundredfold d. thousandfold |
b
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The level below which signal are not transmitted through an ultrasound receiver system is the
a. sensitivity level b. threshold or negative level c. impedance level d. dynamic range level |
b
threshold, negative, reject |
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Gray-scale system typically use ___ as a means of signal dynamic range reduction.
a.rejection b. compression c. relaxation d. elimination |
b
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The strength of the echo is related to the height of the deflection on the oscilloscope for the ______ display.
a. A-Mode b. B-mode c. B-scan d. M-Mode |
a
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Which of the following is not a method for restricting the dynamic range of the signal
a. suppresion b. rejection c. compression d. relaxation |
d
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Most of the scan converters currently use are of the ___ type.
a. analog b. digital c. bistable d. static |
b
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The fraction of time that the pulsed US is actually on is the
a. duty factor b. frame rate c. cavitation d. intensity transmission coeeficient |
a
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The ability of an imaging system to detect weak reflections
a. compression b. demodulation c. gain d. sensitivity |
d
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The major factor in determining the acoustic power output of the transducer is the
a. size of the transducer b. magnitude of the voltage spike c. amount of amplification at the receiver d. amount of gain |
b
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Two primary mechanisms that produce sound changes in cells or tissues are
a. oscillations and radiation b. absorption and reflection c. direct and indirect d. thermal and cavitational |
d
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The ____ relates bandwidth to operating frequency
a. near zone b. piezoelectric crystal c. quality factor d. far zone |
C
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The extraneous beams of ultrasound generated from the edges of individual transducer elements and not in the direction of the main ultrasonic beam are called
a. a phased array b. impedance artifact c. side lobes d. acoustic errors |
c
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The product of the period and the number of cycles in the pulse is the
a. pulse repetition frequency b. continuous wave c. pulse repetition period d. pulse duration |
D
PD = # of cycles x PRP |
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The substance typically used as the matrix on the imaging surface of an analog scan converter tube is
a. mercurous chloride b. silicon oxide c. manganese sulfide d. lithium floride |
B
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Specular reflection occurs when
a. the frequency is small compared with the wavelength b. the object that causes the reflection is small c. the reflector surface is smooth as compared with the wavelength d. the angle of incidence and the angle of reflection differ by at least 45 degree |
c
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The refractive index of water is slightly altered when a sound beam passes through it, thus causing compression and rarefraction of the water molecules. The phenomenon is the basis for the technique of beam measurement
a. isoamplitude b. Schlieren c. relative echo d. attenuator calibration |
b
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Artifacts appearing as parallel, equally spaced lines are characteristic of
a. acoustic shadowing b. off-normal incidence c. specular reflection d. reverberation |
d
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An increase in reflection amplitude from reflectors that lie behind a weakly attenuating structure is called
a. the incidence angle b. enhancement c. the intensity reflection coeeficient d. effective reflecting area |
b
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The amount of dispersion in the far field of an ultrasound beam can be decreased by
a. using a transducer with a convex face b. using a large diameter transducer c. decreasing the intensity of the beam in the near field d. using a lower frequency transducer |
b
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Longitudinal or axial resolution is directly dependent on
a. depth of penetration b. spatial pulse length c. damping d. the angle of incidence |
b
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The transducer ____ is equal to the ratio of the operating frequency to the frequency bandwidth.
a. frequency b. Q factor c. resolution d. polarity |
b
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The technique that uses an optical system to produce a visible image of an ultrasonic beam is the ___ technique.
a. M-mode b. B-scan c. Schlieren d. kinetic scanning |
c
optical system= Schleiren |
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Which of the following is the least obstacle to the transmission of ultrasound?
a. muscle b. fat c. bone d. blood |
d
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The ratio of the largest power to the smallest power that the ultrasound system can handle is the
a. dynamic range b. gain c. rejection d. amplification factor |
a
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Ultrasound waves in tissue are called ____ waves.
a. shear b. lateral displacement c. rotational vibration d. longitudinal |
d
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All except the following can be checked when the test object is scanned from the top only
a. axial resolution b. lateral resolution c. vertical distance calibration d. horizontal distance calibration |
b
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Which of the following parameters cannot be evaluated by the AIUM test object?
a. gray scale b. dynamic range c. azimuthal resolution d. depth resolution e. a and b f. all of the above |
e
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Scanning a test object from three sides without erasing would be used to check
a. gray scale b. depth resolution c. horizontal distance calibration d. registration e. all of the above |
d
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When using the AIUM test object, which of the following should be kept constant for comparisons?
a. output power b. TGC c. reject d. transducer, MHz, and focus e. all of the above |
e
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Which type of ultrasound machine can be used with the AIUM test object?
a. linear array b. static scanner c. phased array d. annular array e. sector scanner f. all of the above g. a and c only |
f
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There are many types of natural and synthetic crystals that possess and exhibit piezoelectric properties. Which of the following are not natural?
a. tourmaline b. quartz c. lead zirconate titanate (PZT-4 or PZT-5) d. barium titanate e. rochelle salt f. lithium sulfate g. lead metaniobate h. ammonium dihydrogenate phosphate |
cdfgh
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Which of the following materials would not be suitable as acoustic insulators for transducer backing.
a. cork b. rubber c. oil d. araldite loaded with tungsten powder e. epoxy resin f. b and e only g. all of the above |
c
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Ultrasound can be described as a (an)
a. mechanical vibration that can be transmitted through matter b. mechanical vibration that can be transmitted through a vacuum c. electromagnetic wave that can be transmitted through tissues d. x-ray that can be transmitted through soft tissues |
a
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If the ultrasound beam is below 16 Hz it is called
a. infrasound (subsonic) b. audible sound c. ultrasound d. x-rays |
a
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If the frequency of sound is above 20 kHz is called
a. infrasound (subsonic) b. audible sound c. ultrasound d. x-rays |
c
infrasound= <20Hz audible = 20Hz to 20 kHz |
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If the frequency of sound is between 16 Hz and 20 kHz it is called
a. x-rays b. audible sound c. ultrasound c. infrasound (subsonic) |
b
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The term Hertz denotes
a. density b. milliwatts per centimeter square c. kilogram d. cycles per second |
d
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Which of the following is not among the spectrum of electromagnetic waves?
a. x-rays b. ultrasound c. ultraviolet d. infrared e. visible light |
b
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An ultrasound transducer converts
a. electrical energy into light and heat b. electrical energy into mechanical energy and vice versa c. mechanical energy into radiation d. sound into ultrasound |
b
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Which of the following is (are) an example(s) of a transducer
a. battery b. loudspeaker c. light buld d. human being e. all of the above f. none of the above g. a and b only |
e
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When electric voltage is applied on both faces of a piezoelectric crystal, the crystal will
a. increase in size b. decrease in size c. lose its polarization d. increase or decrease in size depending on the voltage polarity |
d
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The abbreviation 5 MHz denotes
a. 5 hundred thousand cycles per second b. 5 hundred million cycles per second c. 5000 cycles per second d. 5 million cycles per second |
d
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The function of the damping material in the transducer housing is to
a. reduce pulse duration b. improve axial resolution c. reduce spatial pulse length d. improve lateral resolution e. a and b f. a and d only g. a, b, and c only |
g
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What is the velocity of ultrasound in human soft tissue at 37 degree C?
a. 1540 m/s b. 1540 miles per second c. 741 miles per hour d. 1087 meters/second |
a
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In physical science, the word period denotes
a. the pressure or height of a wave b. the speed of a wave c. the time it takes to complete a single cycle d. propagation |
c
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Longitudinal waves are characterized by
a. motion of particles parallel to the axis of wave propagation b.motion of particles perpendicular to the axis of the wave c. twisting action of the particles in motion d. surface vibrating particles |
a
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Transverse waves are characterized by
a. motion of particles parallel to the wave propagation b. surface vibrating particles c. motion of particles perpendicular to the axis of wave propagation d. twisting action of the particles in motion |
c
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Ultrasound wave propagation causes displacement of particles in a medium. The region of greatest particle concentration are called
a. acoustic impedance b. condensations c. rarefractions d. attenuation |
b
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Ultrasound wave propagation causes displacement of particles in a medium. The regions of lowest particle concentration are called
a. acoustic impedance b. condensations c. rarefractions d. attenuation |
c
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The prefix piezo- is derived from a Greek word that denotes
a. electric b. transducer c. crystal d. pressure |
d
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Axial resolution is
a. the ability to distinguish two objects parallel to the ultrasound beam b. the ability to distinguish two objects perpendicular to the ultrasound beam c. the same as depth, longitudinal and range resolution d. the same as azimuthal, arngular and transverse resolution e. both a and d f. both a and c |
f
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Lateral resolution is
a. the ability to distinguish two objects parallel to the ultrasound beam b. the ability to distinguish two objects perpendicular to the ultrasound beam c. the same as depth, longitudinal and range resolution d. the same as azimuthal, angular and transverse resolution e. both a and b f. both b and d |
f
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If frequency increases, the wavelength will
a. decrease b. increase c. increase 10 times d. remain the same |
a
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If frequency decreases, wavelength will
a. decrease b. increase c. increase 10 times d. remain the same |
b
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As the frequency increases, the resolution will
a. decrease b. increase c. increase 10 times d. remain the same |
b
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As the frequency increases, the penetration will
a. decrease b. increase c. increase 10 times d. remain the same |
a
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As the frequency increases, the beam width will
a. increase b. decrease c. increase 10 times d. remain the same |
b
high freq= shorter pulse, narrow beam width |
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Ultrasound has difficulty propagating through
a. air b. bone c. BaSO4 d. IVP contrast e. all of the above f. a, b and c only g. a and b only |
f
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Which of the following cannot be used as a coupling medium
a. water b. saline c. barium sulfate d. aqueous gels |
c
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Attenuation denotes
a. progressive weakening of the sound beam as it travels b. density of tissue and the speed of sound in the tissues c. the redirection of the ultrasound back to the transducer d. bending of the transmitted wave after crossing an interface |
a
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The piezoelectric effect can be described as
a. density of tissue and the speed of sound in the tissues b. mechanical deformation that results from high voltage applied on faces of the crystal and in turn generates ultrasound c. piezoelectric crystals subjected to pressure resulting in electrical charge appearing on their surfaces d. having a damaging effect on the crystal due to high voltage |
c
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The reverse piezoelectric effect can be best described as
a. density of tissue and speed of sound in the tissue b. mechanical deformation that results from high voltage applied on the face of the crystal and as a result generates ultrasound c. piezoelectric crystals subjected to pressures resulting in lelectrical charges appearing on their surfaces d. having a damaging effect on crystal due to high voltage |
b
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The parameter used to express attenuation is
a. (Z2-Z1/ Z2 +Z1)^2 x 100 b. dB = 10 log10 I2/I1 c. Z = pV d. sin i/ sin r = V1/V2 |
B
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A waveform transfers ___ from one point in space to another point in space
a. particles b. matter c. energy d. mass |
c
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In a mechanical wave, there are material particles that
a. oscillate around an equilibrium point b. move forward at a set rate c. move away from an equilibrium point d. move backward at a set rate |
a
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Wavelength is a measure of
a. time b. voltage c. distance d. pulse duration |
c
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Ultrasonic waves are
a. mechanical b. x-ray c. electromagnetic d. solar |
a
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Acoustic impedance is
a. the amount of tissue x the speed of sound in tissue b. the density of tissue x the speed of sound in tissue c. the transducer frequency x the speed of sound in tissue d. the distance from one interface to the next |
b
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Amplitude is measured in
a. W/cm2 b. A =p V c. sin i/ sin r = V1/V2 d. dB |
d
amplitude= height of the wave dB 20 log |
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The spectrum of ultrasonic frequency is
a. less than 20 Hz b. above 20,000 Hz c. 20-20,000 Hz d. 1-3 million Hz |
b
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Period is inversely proportional to
a. velocity b. watts c. hertz d. frequency |
d
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As the ultrasound beam becomes more perpendicular to the organ interface
a. scattering becomes greater b. there are more refracted echoes c. there are fewer specular echoes d. there are more specular echoes |
d
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A dB describes the
a. ratio of two sound intensities b. sum of two sound intensities c. amount of scattering d. velocity of sound waves |
a
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Axial resolution is also known as all of the following except
a. depth b. range c. azimuthal d. longitudinal |
c
LARD |
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Which of the following has the highest sound velocity?
a. soft tissue b. bone c. air d. water |
b
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According to AIUM, no significant biologic effects have been proven in mammals exposed to
a. SPTA intensities above 100 mW/cm2 b. SPTA intensities below 100 mW/cm2 c. SPTP intensities below 10 mW/cm2 d. SATP intensities below 2 mW/cm2 |
b
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Temporal peak intensity is measured at
a. the time the pulse is present b. the center of the beam c. the time cavitation occurs d. none of the above |
a
"tiempo" is time in Spanish |
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Which of the following has the lowest intensity?
a. SPTP b. SATP c. SPTA D. SATA |
d
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What is the definition of beam uniformity ratio?
a. SA/SP b. SP/SA c. TA/SA d. TP/SP |
b
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The duty factor of a pulsed echo system is normally less than
a. 10% b. 100% c. 1% d. 25% |
c
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A shortened spatial pulse length results in
a. better lateral resolution b. low frequency c. poor resolution d. better axial resolution |
d
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The equation for measuring the relationship among velocity, frequency, and wavelength is
a. (Z2-Z1/ Z2+Z1)^2 x 100 b. V = f x wavelength c. Z = pV d. sin i/sinr = V1/V2 |
b
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Attenuation by an ultrasound beam can occur by
a. divergence of a beam b. scattering c. reflection d. all of the above |
d
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Attenuatio coefficient of sound can be defined by which of the following units?
a. dB/cm/MHz b. dB/cm2/Hz c. cm/Hz/dB d. m/dB/cm3 |
a
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If the transducer Q is low, the bandwidth will be
a. narrow b. high c. wide d. low |
c
Q = Operating frequency / bandwidth |
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Axial resolution can be improved by
a. reducing the SPL b. increasing the SPL c. lowering the transducer frquency d. all of the above |
a
short SPL, damping, high frequency transducer |
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Axial resolution is primarily affected by
a. beam width b. spatial pulse length c. strength of the echo d. velocity of the medium |
b
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Which of the following will improve both axial and lateral resolution?
a. short pulse length b. narrow beam width c. increase beam diameter d. increase transducer frequency |
d
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All of the following are also known as lateral resolution, except
a. azimuthal b. transverse c. range d. angular |
c
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Continuous wave Doppler has a duty factor of
a. less than 1% b. 100% c. greater than 100% d. 50% |
b
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Acoustic impedance is defined as
a. density x propagation speed b. frequency x propagation c. elasticity + propagation d. density x elasticity |
a
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Acoustic impedance is defined by which of the following
a. rayon b. meters/dB c. mW/cm2 d. rayls |
d
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Acoustic impedance is not dependent on which of the following
a. frequency b. density c. stiffness d. none of the above |
a
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The height of the vertical spike on the A-mode display corresponds to
a. the strength of the echo b. the distance to the reflector c. round trip time of the echo d. the pulse repetition frequency |
a
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B-mode ultrasoun includes all of the following except
a. static scans b. M-mode scans c. real-time scans d. all of the above are B-mode |
b
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The correct equation for calculating the percentage of reflection
a. R = (Z2-Z1/Z2+Z1)^2 x 100 b. R = Z1 xZ2 / 2 |
a
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The reflection coefficient between water and air is
a. 1% b. 50% c. 75% d. nearly 100% |
d
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What happens to the ultrasound beam beyond the critical angle
a. 100% is transmitted b. 100% is reflected c. 75% is transmitted, 25% is reflected d. 75% is reflected, 25% is transmitted |
b
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Rayleigh scattering occurs if the particle dimensions are
a.less than the wavelength b. greater than 3 mm c. greater than the wavelength d. none of the above |
a
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One of the acoustic parameters that determines the intensity of an ultrasound wave is
a. waveform b. particle displacement c. period d. power |
d
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I = P/area
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The ability to resolve structures lying perpendicular to the axis of the ultrasound beam is called
a. lateral resolution b. axial resolution c. depth resolution d. longitudinal resolution |
a
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Power is defined as energy per unit
a. mass b. distance c. time d. force |
c
amount of work/ energy transferred done per unit time |
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In most soft tissue the attenuation coefficient varies approximately
a. inversely with frequency b. with the square of the frequency c. logarithmically with frequency d. directly with frequency |
d
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Ultrasound absorption in a medium results in
a. conversion of ultrasound into heat b. dissipation if US into x-rays c. conversion of US into visible light d. dissipation of US into gamma rays |
a
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The typical value of attenuation in soft tissue is
a. 2 dB/cm2/Hz b. 1 dB/cm/Hz c. 2 dB/cm2/MHz d. 0.5 dB/cm/MHz |
d
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False echoes are produced by
a. reflection b. rarefraction c. reverberation d. diffraction |
c
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Approximately what percentage of the US beam will be transmitted between fat and muscle?
a. 1% b. 10% c. 50% d. 99% |
d
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Huygen's principle describes
a. multiple point sources b. refraction c. velocity d. cathode ray tubes |
a
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Enhancement occurs posterior to
a. strong attnuations b. weak attenuations c. strong diffractors d. weak diffractors |
b
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The role of sound attenuation in tissue is expressed in terms of
a. half value layer b. Huygen's principle c. duty cycle d. spatial peak |
a
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Improper location of an echo may be due to
a. shadowing b. Huygen's principle c. density error d. propagation speed error |
d
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The range equation explains
a. side lobes b. distance to reflector c. attenuation d. calibration |
b
d= ct/2 |
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For a specular reflector
a, the angle of incidence is equal to the angle of reflection b. the angle of incidence is greater than the angle of reflection c. there is no dependence on beam angle d. the angle of incidence is equal to the angle of transmission |
a
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Which of the following is determined by the medium
a. intensity b. period c. propagation speed d. amplitude |
c
Intensity, period and amplitude by the sound source |
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Which of the following is not an acoustic variable
a. density b. pressure c. temperature d. force |
d
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The acronym TGC denotes
a. tissue gain characteristic b. time gain compensation c. transducer generation control d. temperature generator control |
b
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The propagation speed for fat is
a. higher than 1540 m/s b. lower than 1540 m/s c. equal to 1540 m/s d. cannot be measured |
b
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Which of the following has a propagation speed closest to the average soft tissue
a. bone b. air c. fat d. muscle |
d
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Arrange the following media in terms of propagation velocity, from lowest to highest
a. air, fat, muscle, bone b. bone, fat, air, muscle c. bone, muscle, fat, air d. muscle, air, fat, bone |
a
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As frequency increases, backscatter
a. decreases b. is not affected c. increases d. is reflected |
c
increasing frequency and increasing heterogenous media |
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The angle at which total reflection occurs is called
a. critical angle b. warp angle c. reflectivity angle d. diffraction angle |
a
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The pulse repetition frequency is the number of pulses occuring per
a. wave b. returning echo c. microsecond d. second |
d
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The unit (s) used for the duty factor is (area)
a. rayls b. m/s/Hz c. m/us/MHz d. unitless |
d
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The typical value for attenuation coefficient for 6 MHz ultrasound in soft tissue is
a. 3 dB/cm b. 1 dB/cm/Hz c. 3 dB/cm2 d. 2 dB |
a
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Normal incidence occurs when the ultrasound beam travels _____ to the boundary between the two media
a. parallel b. perpendicular c. obliquely d. at 1540 m/s |
b
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The amount of energy transmitted and/or reflected at the boundary between two media depends on
a. acoustic impedance mismatch b. the frequency of the beam c. the propagation speed of the first medium d. the propagation speed of the second medium |
a
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which of the following has a higher acoustic impedance coefficient
a. solid b. liquid c. gas d. all the above have an equal acoustic impedance |
a
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According to Snell's law, the transmission angle is greater than the incidence angle if the propagation speed
a. of medium 2 is greater than that of medium 1 b. of medium 1 is greater than that of medium 2 c. of the two media are equal d. is calculated at 3 dB down |
a
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According to the range equation, which of the following are necessary to calculate the distance to the reflector
a. attenuation coefficient and type of reflector b. density and type of reflector c. propagation speed and pulse round-trip time d. density and pulse round-trip time |
c
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The mirror image artifact is commonly seen around which of the following structures?
a. kidney b. pancreas c. spleen d. diaphragm |
d
strong reflectors |
|
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The comet tail artifact can be seen posterior to an object that has
a. a much lower acoustic impedance than its surroundings b. a much higher acoustic impedance thanits surroundings c. either a much lower or much higher acoustic impedance that its surroundings d. the same acoustic impedance as its surroundings |
c
reverberation artifact greater impedance mismatch |
|
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Which of the following may produce the comet tail artifact
a. liver-kidney interface b. spleen-kidney interface c. tissue-gas interface d. gas-fluid interface |
c
high acoustic impedance mismatch |
|
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If the ultrasound beam passes through a mass in the liver that contains fat, how might the diaphragmatic echo posterior to it appear?
a. closer than it really is b. farther than it really is c. will not be affected d. will not be visualized |
b
fat tissue has lower propagation speed than the assumption of 1540 m/s |
|
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Bandwidth can be increased by
a. increasing the Q factor b. increasing the frequency c. increasing the pulse length d. increasing damping |
d
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Which of the following is not a control affecting the amplification of echoes?
a. output b. compression c. time gain curve d. balance |
a
output is increasing the signal to noise ratio |
|
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On some sonographic equipment, adjusting the compression will affect which of the following processes?
a. slope position b. dynamic range c. output d. balance |
b
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Generally, ultrasound transducers have
a. better axial resolution than lateral resolution b. better lateral resolution than axial resolution c. better azimuthal resolution than radial resolution d. equal axial and lateral resolution |
a
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The pulse repetition frequency of an ultrasound unit is typically
a. 1 Hz b. 10 Hz c. 100 Hz d. 1000 Hz |
d
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B-mode display denotes
a. basic modulator b. beam motion c. beam modulator d. brightness modulation |
d
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What percentage of the time is a typical pulsed ultrasound system capable of receiving echoes?
a. 100% b. 99.9% c. 75% d. 50% |
b
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If the frequency doubles, what happens to the wavelength?
a. increase fourfold b. increases twofold c. decreases by one-half d. no relationship to wavelength |
c
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Which of the following does not display a sector format
a. linear-sequence array b. electronic-phased array c. mechanical rotating wheel d. mechanical wobbler |
a
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Which of the following are most commonly used in ultrasound transducers?
a. lead zirconate titanate (PZT) b. barium sulfate c. metaniobate d. quartz |
a
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Transmit-delay focusing in a linear array transducer will
a. improve axial resolution b. improve lateral resolution c. improve frequency d. decrease the depth of penetration |
b
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For real-time systems, which of the following is not related to the others?
a. frame rate b. lines per frame c. pulse repetition frequency d. frequency |
d
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The pulse repetition frequency is
a. pulses emitted per second b. time from the beginning of one pulse to the beginning of the next c. the time during which the pulse actually occurs d. cannot be defined |
a
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Which of the following is not a role of the pulser?
a. driving the transducer b. telling the receiver when the US pulses are produced c. telling the memory when the ultrasound pulses are produced d. beam steering |
d
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Demodulation is the process of
a. converting the voltage delivered to the receiver from one form to another b. decreasing the differences between the smallest and largest amplitude c. eliminating the smaller amplitude voltage produced by electronic noise d. rejecting weak echoes to reduce noise |
a
rectification and smoothing |
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Which of the following are not operator adjustable?
a. compensation and rejection b. amplification and compensation c. demodulation and rectification d. rejection and amplification |
c
smoothing and rectification is a form of demodulation |
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Which of the following varies with distance from the transducer?
a. lateral resolution b. frequency c. axial resolution d. spatial pulse length |
a
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Increasing axial resolution by increasing frequency also results in
a. increasing penetration b. decreasing half-intensity depth c. decreasing the PRF d. none of the above |
b
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Reflection refers to
a. the bending of the ultrasound beam as it crosses a boundary b. conversion of ultrasound to heat c. redirection of a portion of the ultrasound beam from a boundary d. the scattering of the ultrasound beam in any direction |
c
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Digital computers use a special number system called
a. digital number system b. alphanumeric system c. chronologic system d. binary number system |
d
0 and 1 |
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The term bit in computer science denotes
a. binary digit b. buffer c. baud rate d. BASIC programming |
a
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An 8-bit binary number is referred to as
a. byte b. baud rate c. buffer register d. BUS |
a
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Which of the following is not an example of computer hardware?
a. monitor b. program c. disk drive d. printer |
b
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The acronym RAM denotes
a. reset-auxiliary memory b. random- access memory c. retailing American microcomputers d. retailing American machine |
b
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The acronym ROM denotes
a. read-only memory b. read-only modem c. reatiling -only microcomputer d. run-output machine |
a
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Which of the following is not an input device?
a. keyboard b. printer c. disk drive d. magnetic disk |
b
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The type of permanent memory that is produced at the time of manufacture and cannot be changed by the computer user is called
a. RAM b. ROM c. PROM d. EPROM |
b
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The type of programmable memory that allows the user to write, store, or erase data is called
a. PLA b. ROM c. PROM d. EPROM |
d
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The acronym CPU denotes
a. computer program update b. central processing unit c. capacitor power unit d. computer portable unit |
b
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The most common binary word length in microprocessors
a. 8,16, 32 bits b. 12 or 24 bits c. 128K bytes d. 64K |
a
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An 8-bit word microcomputer with 128k words of memory can store how many bits of data?
a. 1000 b. 128,000 c. 1,048,576 d. 128 |
c
K =1024 128x 1024 x 8 |
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The contents of EPROM can be completely erased by which of the following applications?
a. light waves b. infrared c. ultrasound d. ultraviolet light |
d
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A sonographic image can be transfered from one computer to another by way of
a. fixed disk drive b. modem c. printer d. keyboard |
b
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The most commonly used programming language for personal computers is
a. COBOL b. FORTRAN c. BASIC d. LOGO |
c
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The unit for measuring the speed of data communication is called
a. buffer b. booting c. output unit d. baud rate |
d
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Which of the following disks has the highest storage capacity and fastest access time?
a. 3 1/2 in microfloppy double density b. hard disk c. 5 1/4 in minifloppy d. 3 1/2 in microfloppy high density |
b
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The acronym BASIC denotes
a. basic American scientific instructional code b. basic American scientific information center c. beginner's all purpose symbolic instruction code d. business application software information center |
c
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A modem is an electronic device that
a. simulates human voice b. prints data c. translates signal from digital into analog and analog to digital d. senses data from card inserted into it |
c
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Each binary digit in a binary number is represented in memory by a memory element, which at any time is in one of ___ states.
a. many b. two c. none of the above |
b
0 and 1 |
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In binary numbers, how many values are used for each digit?
a. 10 b. multiples of 10 c. 2 d. 5 |
c
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The number 30 in binary is
a. 0110 b. 1110 c. 1001 d. 1111 e. none of the above |
e
above 15 is 5 digit binary number |
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How many gray levels (echo amplitude levels)can a 4-bit deep digital scan converter store?
a. 2 b. 4 c. 8 d. 16 e. 32 |
d
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An ultrasound instrument that could represent 64 shades of gray would require a (n) bit memory
a. 8 b. 6 c. 4 d. 16 |
b
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Which of the following are effects seen in tissue at high ultrasound intensities?
a. fusion, ionization b. heating, cavitation c. expansion, encrustation d. reabsorption, dehydration |
b
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Which of the following is correct list for functions performed by the receiver system in the ultrasound machine (B-scanner)?
a. inspection, detection, correction, rejection,depression b. randomization, amplification, modulation, rectification, limitation c. amplification, compensation, compression, rejection d. expansion, contraction, band limitation, sonification |
c
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A large amplitude pulse from the pulser results in
a. a long duration pulse from the transducer b. a short duration pulse from the transducer c. shutdown of the receiver d. a large amplitude pulse from the transducer e. a large amplitude pulse from the display |
d
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Voltage pulses from the pulser go to the
a. transducer and display b. transducer and receiver c. transducer and TGC control d. display and image memory e. amplifier and receiver |
b
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The five major components of a pulse-echo ultrasound system are
a. flux capacitor, image memory, transducer, scan arm, amplifier b. interrossitor, pulser, receiver, display, power supply c. image memory, display, scan arm, TGC control, foot switch d. transducer, receiver, image memory, pulser, display |
d
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Transducers are focused by two major methods: internal focusing and external focusing. These methods can be accomplished by
a. thickening the crystal and adding water path b. cutting a curved transducer element and/or using an acoustic lens c. "doping" the crystal with metal ions and damping d. using a crystal pulse and a bandwidth limiter e. all of the above will focus a transducer element |
b
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The unit applied to the Q factor that describes the ratio of operating frequency to bandwidth is called
a. megahertz b. percent c. millimeter per second d. Fresnel e. none of the above, Q factor is unitless |
e
q factor = operating freq/bandwidth |
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T or F
Acoustic shadow is a reduction in echoes from a region distal to an attenuating structure. |
T
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Acoustic enhancement is an increase in echoes from a region distal to a weakly attenuating structure or tissue.
|
T
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T or F
Anechoic means without echoes |
T
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Artifact is an echo that does not correspond to the real target.
|
T
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Echogenic is a structure that possesses echoes.
|
T
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Hyperechoic, echoes of higher amplitude than the normal surrounding tissues.
|
T
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Hypoechoic are echoes of lower amplitude than the normal surrounding tissues.
|
T
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T or F
Interface is the surface forming the boundary between two media having different acoustic impedances. |
T
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Sonolucent structure is a tissue or structure that does not have internal echoes. Sonolucent is a misnomer for anechoic.
|
T
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The backing material that is usually constructed in a continuous-wave Doppler transducer is
a. epoxy resin b. cork c. air d. tungsten |
c
CW transducer= air-backed or no backing |
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Transducer with continuous-wave operation are commonly used in which of the following applications?
a. diagnostic, surgical, therapeutic and Doppler b. diagnostic and surgical c. diagnostic and Doppler d. surgical, therapeutic and Doppler |
d
PW = diagnostic |
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Which of the following waves are visible under normal conditions?
a. water waves b. x-ray waves c. radio waves d. sound waves |
a
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Ultrasound can travel in all of the following, except
a. IVP contrast b. solid tissue c. vacuum d. blood |
c
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The time it takes to complete a single cycle is called
a. period b. wavelength c. frequency d. velocity |
a
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The wave vibration at 20 cycles per second has a frequency of
a. 20 Mhz b. 20 Hz c. 20 kHz d. 120 kHz |
b
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a wave vibrating at 1 million cycles per second has a frequency of
a. 1 GHz b. 1 kHz c. 1 MHz d. 100 MHz |
c
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The device that produces the ultrasound beam is commonly called a
a. cathode-ray tube (CRT) b. scan converter c. transducer d. mechanical arm |
c
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T or F
A-mode is a graphical presentation with vertical spikes arising from a horizontal baseline; the height of the vertical spikes represents the amplitude of the deflected echo. |
T
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B-mode is a two dimensional image of internal body structures displayed as dots; the brightness of the dots is proportional to the amplitude of the cho; the image is both applicable to real-time and static scanners.
|
T
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M-Mode is a graphical presentation of moving structures in a waveform; the display is presented as a group of lines representing the motion of moving interfaces versus time.
|
T
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Which of the following is not an essential part of the CRT?
a. electron gun b. flourescent screen c. silicon d. deflection system (horizontal and vertical plates) |
c
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The CRT used in ultrasound usually encloses
a. air b. vacuum c. oil d. gas |
b
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The positively (+) charged CRT terminal is called the
a. anode b. cathode c. both anode and cathode |
a
cathode = (-)charged, attracts cations (+) anode = (+, attracts anions (-) charged electron |
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The intensity of the US beam
a. is measured in watts b. is always constant c. depends on the beam diameter d. is measured with AIUM phantom |
c
I = power/ beam cross sectional area |
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Whose principle states, " all points on an ultrasound waveform can be considered as point sources for the production of secondary spherical wavelets"?
a. Doppler's b. Curie's c. Huygen's d. Young's |
c
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The fraction of time that a pulsed ultrasound system is actually producing ultrasound is called the
a. duty factor b. curie factor c. frame rate d. transmission factor |
a
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Real time ultrasound instrumentation can be classified as
a. annular, sector, linear, and static scanners b. sector scanners only c. sector, linear, and annular scanners d. static scanners only |
c
sector - Linear phased array (pie shaped) - wobbler rotating wheel (pie shaped) linear sequenced array - rectangular annular- mechanical and electronic |
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The speed at which ultrasound propagates within a medium depends primarily on
a. its frequency b. the compressibility of medium c. its intensity d. the thickness of the medium |
b
stiffnes |
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An artifact that results from a pulse that has traveled two or more round-trip distances between the transducer and the interface is called
a. a multipath b. a side lobe c. reverberation d. scattering |
c
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The ratio of output electric power to input electric power is termed
a. power b. intensity c. gain d. voltage |
c
Gain is the ratio of electric power |
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Multipath artifacts result from
a. echoes that return directly to the transducer b. shotgun pellets c. echoes that take an indirect path back to the transducer d. none of the above |
c
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A scan converter will accept echo signals from the receiver and store them in the "memory" of the instrument. Identify the types of memory used in scan converters.
a. gray scale and bistable b. analog and digital c. static and real-time d. none of the above |
b
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To achieve the best possible digital representation of an analog system, the echo signal should undergo
a. postprocessing b. preprocessing c. rectification d. amplification |
b
echoes -analog to digital (preprocessing) |
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Near zone length may be increased by increasing
a. wavelength b. wavelength and bandwidth c. transducer diameter d. frequency and transducer diameter |
d
NZL = transducer diameter^2f / 6 |
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Which of the following is a true definition of a true damped transducer?
a.increased efficiency, sensitivity and spatial pulse length b. decreased efficiency, sensitivity and spatial pulse length c. increased efficiency and sensitivity but decreased spatial pulse length d. decreased efficiency but increased sensitivity and spatial pulse length |
b
damping renders poor sensitivity and efficiency but better axial resolution |
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Gain compensation is necessary due to
a. reflector motion b. gray scale c. attenuation d. resolution |
c
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The frequency bandwidth may be determined by which of the following?
a. spectral analysis b. Schlieren system c. hydrophone d. cathode analysis |
a
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Analog scan converters
a. function perfectly as peak deflectors b. have greater image sharpness than digital scan converters c. store any increment of signal amplitude d. have better image uniformity than digital scan converters |
c
digital storage is in discrete steps |
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The gray-scale resolution for a 5-bit digital instrument that has a dynamic range of 42 dB is
a. 1.9 dB b. 3 dB c. 1.3 dB d. 0.07 dB |
c
1. det # of shades in 5-bit digital system 2 ^5 = 32 dynamic range /levels 42/32 =1.3 |
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If it takes 0.01 sec for a pulse emitted by the transducer to reach an echo source of soft tissue, what distance must the pulse travel in order to be recorded?
a. 1540 cm b. 30.8 m c. 15.4 m d. both a and c |
b
d= ct multiply by 2 (round trip) |
|
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An artifact that is produced from interaction of the incident beam with a curved surface and results in an acoustic shadow referred to as
a. a ghost artifact b. an edge artifact c. a comet tail artifact d. a ring down artifact |
b
ex. fetal skull |
|
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|
An artifact that results from refraction of the ultrasound beam at a muscle-fat interface and gives rise to double image.
a. a split-image artifact b. an edge artifact c. a comte tail artifact d. ring-down artifact |
a
also called ghost-image artifact muscle-fat interface |
|
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|
An artifact that would least likely produce a pseudomass
a. comet tail artifact b. a multipath artifact c. mirror image artifact d. slide lobe artifact |
a
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Split image artifact is more noticeable in
a. athletic patients and mesomorphic habitus patients b. patients with underdeveloped rectus muscle c. mesomorphic habitus patients and patients with underdeveloped rectus muscle d. all of the above |
a
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|
Select the least-likely cause or causes for a split image artifact
a. abdominal scar b. lateral margins of the rectus muscles c. gas bubble d. refraction of the sound beam at a muscle-fat interface |
c
muscle= sudden change in prop speed |
|
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|
The most likely cause for a beam thickness artifact is
a. metallic surgical clips b. gas bubble c. partial volume effect d. shotgun pellets |
c
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|
Beam thickness artifact primarily dependent on
a. position of the patient b. gas bubble c. beam angulation d. gravity |
c
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|
Which of the following is not true for side lobe artifact?
a. caused by multiple side lobes of the transducer b. apparent in real-time image c. may be diffuse or specular in appearance d. not visible on real-time image |
d
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|
Which of the following is least likely to produce an acoustic shadow?
a. bone interface b. metallic surgical clips c. gallstones d. gas interface |
b
shotgun pellets and surgical clips = trail of dense continuous echoes bone, gas and gallstone = distal acoustic shadow |
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The amount of splitting that occurs in a split-image artifact for a given-structure
a. can be calculated using Snell's Law b. cannot be calculated because it is an artifact c. can be calculated using the equation Z =pV d. can be calculated using 5 MHz transducer with the equation split (m/s) = D pie/T |
a
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|
The most common artifact encountered in patients with shotgun wounds is
a. comet tail artifact b. multipath artifact c. mirror image artifact d. side lobe artifact |
a
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The type of reverberation echo that usually results from a small gas bubble and appears as a high amplitude echo occuring at regular intervals is called
a. multipath artifact b. mirror-image artifact c. side-lobe artifact d. ring-down artifact |
d
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|
The first vertical deflection on the A-mode that corresponds to the transducer face is called
a. bistable b. side lobe c. main bang d. gain |
c
transducer artifact |
|
|
|
The type of real-time system that employs a combination of electronic and mechanical means is called
a. wobbler sector real-time b. rotating wheel real-time c. annular-array real-time d. linear-sequenced array |
c
annular array -mechanical steering and dynamic focusing (electronic) |
|
|
|
If the amount of acoustic coupling medium is insufficient, what changes could result?
a. decrease in amplitude of returning echo b. increase in amplitude of returning echo c. the transducer will slide on the skin surface d. no effect on the image |
a
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|
Which of the following is not a hard copy?
a. x-ray film b. polaroid film c. floppy disk d. videotape recorder |
d
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|
The effects of diagnostic ultrasound on human soft tissue are called
a. sensitivity effects b. biologic effects c. neurologic effects d. pressure effect |
b
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|
The average propagation speed of ultrasound in soft tissue is
a. 1.54 mm/us b. 741 mph c. 1560 m/s d. 331 mm/s |
a
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|
The intensity of ultrasound is measured in
a. kg/m3 b. N/m2 c. Hz d. W/cm2 |
d
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|
There is no known adverse biologic effect in tissue at intensities below
a. 100 mW/cm2 SPTA b. 1000 mW/cm2 SAPA c. 10 W/cm2 SPTP d. 500 m/Wcm2 SATA |
a
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|
The acronym SPTA denotes
a. static probe transmission amplitude b. static proble transmission absorption c. spatial peak temporal average d. sound propagation temperature artifact |
c
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|
The general range of intensities in therapeutic ultrasound
a. 0.5 W/cm2 - 2.0 W/cm2 SPTA b. 0.002 W/cm2 - 0.5 W/cm2 SPTA c. 50 W/ cm2 -100 W/cm2 SPTA d. the general range of intensities in therapeutic ultrasound is unknown |
a
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|
The general range of intensities in diagnostic ultrasound
a. 0.5 W/cm2 - 2.0 W/cm2 SPTA b. 0.002 W/cm2 - 0.5 W/cm2 SPTA c. 50 W/ cm2 -100 W/cm2 SPTA d. the general range of intensities in therapeutic ultrasound is unknown |
b
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|
Which of the following characteristics does not apply to diagnostic ultrasound at normal diagnostic intensity levels?
a. noninvasive b. atraumatic c. ionizing d. nontoxic |
c
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|
The most common result of high intensity ultrasound is
a. cavitation b. brain damage c. fetal developments anomalies d. heat |
d
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|
In the study of bioeffects, cavitation denotes
a. production and behavior of gas bubbles b. necrosis c. cell membrane rupture d. chromosome breakage |
a
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|
The two types of cavitation are
a. silent and noisy b. micro and macro c. membrane and nonmembrane d. stable and transient |
d
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|
An instrument used to detect frequency shift is called
a. Doppler b. real-time c. A-mode d. static scanner |
a
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|
Specular reflections
a. occur when the interface is larger than the wavelength b. occur when the interface is smaller than the wavelength c. arise from interfaces smaller than 3 mm d. are not dependent on the angle of incidence |
a
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Non specular reflections
a. occur when the interface is larger than the wavelength b. occur when the interface is smaller than the wavelegth c. arise from the mirror-like surfaces d. are beam-angle dependent |
b
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|
The acronym SPPA denotes
a. static probe power average b. static probe transmission absorption c. spatial peak pulse average d. sound propagation performance average |
c
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|
The mode not applicable to a Doppler instrument is
a. static b. pulsed c. continuous d. audible |
a
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|
Which of the following transducers would be most useful for imaging superficial structures?
a. 5 MHz, short focus b. 3 MHz, long focus c. 5 MHz, long focus d. 2.5 MHz, short focus |
a
higher frequency is meant for good resolution with less attenuation |
|
|
|
Which of the following transducers would be most useful for good penetration on an obese patient?
a. 5 MHz, short focus b. 3 MHz, long focus c. 5 MHz, long focus d. 2.5 MHz, short focus |
b
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|
The digital memory represents a picture element called a
a. pixel b. bistable c. real-time d. matrix |
a
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|
How many shades of gray can the human eye distinguish?
a. about 16 shades b. between 16 and 32 shades c. more than 64 shades d. more than 124 shades |
a
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|
The most recent digital storage employs what size memory?
a. 512 x 512 x 6-bit deep b. 64 x64 x 4-bit c. 128 x128 x 4-bit deep d. 16 x 16 x 2-bit deep |
a
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|
A disadvantage of pulsed-wave Dopler (PW) relative to continuous-wave Doppler is that
a. it is unidirectional b. the Doppler shift depends on frequency c. it is subject to "aliasing" d. it does not provide in-depth information |
c
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|
Which of the following is (are) essential to a TGC display?
a. static system b. real-time system c. bistable system d. all of the above |
d
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|
What is the effect of ultrasound absorption on tissues at normal intensity levels?
a. dissipation of heat by conduction b. significant temperature elevations c. significantly lowered temperature d. necrosis |
a
heat is removed by conduction |
|
|
|
CRT monitors normally have how many horizontal lines?
a. 16 b. 64 c. 100 d. 525 |
d
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|
How many frames per second are displayed by CRT monitor?
a. 525 b. 30 c. 16 d. 60 |
b
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|
How many times each second does the electron beam scan each field on a CRT monitor in order to produce a flicker-free display?
a. 30 b. 60 c. 40 d. 10 |
b
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|
The dynamic range of the dots on the average oscilloscope or CRT monitor is?
a. 50-60 dB b. 20-25 dB c. 125 dB d. 525 dB |
b
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|
|
The term matrix, when referring to digital memory, denotes
a. number of rows and columns b. analog c. pixel d. buffer |
a
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|
Digital memory resembles
a. squares on a checkerboard b. a transducer c. an electron beam d. hydrophone |
a
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|
A region that is anechoic is diplayed as
a. echo-free b. echogenic c. hyperechoic d. hypoechoic |
a
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|
A region that is hyperechoic is
a. anechoic b. echogenic c. echo-free d. transsonic |
b
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|
Which of the following cannot be measured by a hydrophone?
a. pressure amplitude b. spatial pulse length c. impedance d. intensity |
c
impedance is a property of the medium not the source |
|
|
|
The hydrophone is made up of
a. x-rays b. transducer elements c. ultraviolet lights d. all of the above |
b
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|
Bioeffects at medium intensity levels on laboratory animals have resulted in
a. cancer b. death c. growth retardation d. no effects |
c
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|
|
Which of the following is the least likely cause for attenuation?
a. absorption b. reflection c. refraction d. scattering |
c
|
|
|
|
Absorption refers to
a. bending of the sound beam crossing a boundary b. conversion of sound to heat c. redirection of a portion of the sound from a boundary beam d. redirection of the sound beam in several directions |
b
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|
|
Diffraction refers to
a. spreading out of the US beam b. conversion of sound to heat c. redirection of the portion of the sound from a boundary beam d. bending of the sound beam crossing a boundary |
a
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|
|
The hydrophone is made up of
a. x-rays b. transducer elements c. ultraviolet lights d. all of the above |
b
PVDFs |
|
|
|
Bioeffects at medium intensity levels on laboratory animals have resulted in
a. cancer b. death c. growth retardation d. no effects |
c
|
|
|
|
Which of the following is the least likely cause for attenuation?
a. absorption b. reflection c. refraction d. scattering |
c
|
|
|
|
Absorption refers to
a. bending of the sound beam crossing a boundary b. conversion of sound to heat c. redirection of a portion of the sound from a boundary beam d. redirection of the sound beam in several directions |
b
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|
|
|
Diffraction refers to
a. spreading out of the US beam b. conversion of sound to heat c. redirection of the portion of the sound from a boundary beam d. bending of the sound beam crossing a boundary |
a
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The hydrophone is made up of
a. x-rays b. transducer elements c. ultraviolet lights d. all of the above |
b
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Bioeffects at medium intensity levels on laboratory animals have resulted in
a. cancer b. death c. growth retardation d. no effects |
c
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Which of the following is the least likely cause for attenuation?
a. absorption b. reflection c. refraction d. scattering |
c
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Absorption refers to
a. bending of the sound beam crossing a boundary b. conversion of sound to heat c. redirection of a portion of the sound from a boundary beam d. redirection of the sound beam in several directions |
b
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Diffraction refers to
a. spreading out of the US beam b. conversion of sound to heat c. redirection of the portion of the sound from a boundary beam d. bending of the sound beam crossing a boundary |
a
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Scattering refers to
a. bending of the sound beam crossing a boundary b. conversion of sound to heat c. redirection of a portion of the sound from a boundary beam d. redirection of sound beam in several directions |
d
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The method for sterilizing transducers is
a. heat sterilization b. steam c. recommended by transducer manufacturer d. autoclave |
c
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An example of an acoustic window
a. liver interface b. rib interface c. tissue/air interface d. tissue/bone interface |
a
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The binary number 1010 equals the decimal number
a. 10 b. 11 c. 110 d. 100 |
a
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Real-time imaging is similar to
a. static scanning b. flouroscopy c. MRI d. All of the above |
b
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When attempting to identify fetal heart motion, the frame rate of the real-time system soud be
a. turned off to avoid confusion b. set at a slow rate c. set at a faster rate d. set at five times per second |
c
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Select the recommended orientation for a transverse scan
a. all transverse scans should be viewed from the patient's feet b. all transverse scans should be viewed from the patient's head c.all transverse scans should be viewed lateral from the patient's right side d. all transverse scans should be viewed lateral from the patient's side |
a
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The recommended orientation for longitudinal scan is
a. the patient's head to the right image and feet to the left of the image b. the patient's head to the left of the image and feet to the right of the image c. the patient's head to the top(anterior) of the image and feet to the bottom (posterior) of the image d. none of the above |
b
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Demodulation is a function performed by the
a. pulser b. amplifier c. receiver d. transmitter |
c
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Which of the following statements about ultrasound waves is not true
a. ultrasound waves are mechanical vibrating energy b. ultrasound waves can be polarized c. ultrasound waves are not part of the electromagnetic spectrum d. ultrasound waves cannot travel in a vacuum |
b
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The transducer crystal most likely to be employed in high frequency work, above 18 MHz, is
a. lithium sulfate b. PZT-5 c. Rochelle salt d. quartz |
d
comes from nature/ more stable |
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The advantage that PZT-5 has over other ceramic material is that it is
a. easy to shape b. effective at low voltage c. inexpensive d. all of the above |
d
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The trade name for lead zirconate titanate is
a. BaSO4 b. quartz c. PZT-5 d. synthetic P |
c
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How many shades of gray canbe displayed using a scan converter with 8 bits per memory element
a. 8 b. 16 c. 128 d. 256 |
d
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The transducer that would be best suited for intercostal scanning
a. linear-sequenced array real-time b. mechanical sector real-time transducer c. static with large diameter d. no type of transducer can scan between intercostal space |
b
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The difference between real-time and flouroscopy is
a. ultrasound does not need contrast media b. flouroscopy has potential bioeffects whereas ultrasound has no known biologic effects at normal intensity level c. ultrasound is nonionizing d. a movie-like image is diplayed, whereas real-time displays a single frame image e. all of the above f. a and d g. a, b and c |
g
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Which of the following contrast media used in x-ray do not obscure the propagation of ultrasound
a. BaSO4 for upper GI examination b. Hypaque for IVP examination c. air for lower GI examination d. telepaque for oral cholecystogram e. C and d f. B and d g. none of the above h. all of the above |
f
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Lateral resolution is equal to
a. the wavelength b. the beam diameter c. the near zone length d. the wave number |
b
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Which of the following materials are used to make acoustic lenses?
a. aluminum b. Perspex (acrylic plastic) c. polysterene d. ethylene oxide e. all of the above f. a, b and c g. b and d |
f
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Ultrasound beams can be focused and defocused with the use of
a. a concave or convex mirror b. acoustic lens c. both a and b d. ultrasound beam cannot be focused, only light |
c
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The normal range of wavelength in medical application is
a. 0.1 -1.5 mm b. 1.5- 2 mm c. 2-5 mm d. 5.5 -15 mm |
a
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Which of the following cannot be distiguished on diagnostic ultrasound?
a. tissue b. solid mass c. individual cells d. male and female genetalia |
c
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Density is defined as
a. unit of impedance b. force divided by area c. force multiplied by displacement d. mass per unit volume |
d
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Ultrasound absorption is directly proportional to
a. viscosity b. frequency c. distance d. all of the above |
d
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Duplex imaging combines gray scale with Doppler and can appear as?
a. M-mode and spectrum b. B-mode and spectrum c. color flow imaging and spectrum d. all of the above |
d
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Color flow imaging produces an image composed of
a. tissue echoes in gray scale and blood echoes in color b. soft tissue echoes in gray scale and blood motion in color c. stationary tissues in gray scale and moving tissues in color |
c
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Angiodynography is termed used to describe
a. a form of high resolution color flow imaging b. a form of high resolution MRI c. a new form of imaging relying on high speed propagation velocities in soft tissues d. the coloring of conventional angiograms |
a
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The Doppler effect occurs
a. only to waves more than 1000 m/s b. only to ultrasound waves with intensities greater than 500 mW/cm2, SPTA c. to all waves coming from a moving wave source d. in ultrasound, but only when the targets are moving faster than 1.0 m/s |
c
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The Doppler effect depends on
a. the carrier frequency, the angle between echo source velocity and beam axis and the reflectivity of blood b. the closing velocity between transducer and tissue, carrier frequency, and ultrasound propagation velocity c. the lowest Doppler-shift frequency detectable and the highest frequency without aliasing d. the largest change in acoustical impedance within moving blood |
b
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The calculated blood velocity using color flow imaging a sonographer must
a. place a sample volume in the major streamline or jet within the vessel and set an angle correction parallel to the vessel wall b. assume that all flow is parallel to the vessel wall c. locate the major streamline and place the sampling angle 60 degrees to the vessel wall d. place a sample volume in the major streamline or jet and set the angle correction parallel to the streamline |
d
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To preserve gray-scale texture, digital sampling for gray-scale images must be at intervals of
a. 0.6 mm b. one wavelength or less c. 1.0 mm d. 3 dB |
b
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To preserve flow detail, digital Doppler sampling intervals for a vascular color flow image must be at intervals of
a. 1-2 mm b. 1-2 cm c. one wavelength or more but less than 1 mm d. -6 dB |
c
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Gray scale tissue texture in a color flow imaging system depends on
a. transmit focusing only b. receive focusing only c. the product of transmit and receive focusing d. the speed at which the ultrasound beam is moved by the scan head |
c
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The shape of the sample volume in pulsed Doppler has a major effect on the content of the Doppler signal
a. true b. false |
a
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To form the color patterns in a color flow image, a color flow system samples down each Doppler image line of sight for
a. the amplitude of the Doppler signal b. the velocities of the RBC c. the average Doppler shift frequency d. the velocity spread within the sample site |
c
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The Doppler portion of a color flow image is a map of red-cell velocities
a. true b. false |
b
average Doppler shift frequency |
|
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Separating moving soft tissue from moving blood in a color flow image tests for
a. Doppler signal amplitudes only b. tissue signal amplitudes only c. Doppler signal frequencies only d. the relationship between amplitudes and frequencies of the Doppler signal |
d
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A curving vessel within a color flow image shows color in the vessel when the beam and vessel are parallel and shows no color as the vessel turns. The loss of color means that
a. the vessel is occluded b. the vessel is open, but the blood velocity is too low to complete the image c. the dark region is diseased d. the Doppler effect works only when the vessel is parallel to the ultrasound beam |
b
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The smallest vessel that appear in a color flow image are about 1 mm diameter. The smaller vessels are absent because
a. arterial blood velocities are too low in vessels that are less than 1 mm in diameter b. the smaller vessels are shadowed by the surrounding soft tissue c. soft tissue does not have many vessels that are less than 1 mm in diameter d. the smaller vessels do not reflect ultrasound as well as the larger vessels do |
d
small echo signal |
|
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The color flow image provides information on (1) the existence of flow
(2) the location of flow in the image (3) flow direction relative to transducer (4) the maximum flow velocity a. all of the above b. 1, 3 and 4 c. 3 and 4 d. 1, 2, and 3 |
d
velocity= spectral |
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One begins reading a color flow image by
a. determining the maximum systolic frequency b. knowing the position of the scan plane on the patients body c. knowing the direction of flow relative to the transducer |
b
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Changes in the Doppler shift frequencies within a color flow image sample site appear in the image as
a. nothing; the image only shows changes in phase b. different colors (hues) c. different levels of color saturation (purity) d. different colors (hues) or different levels of saturation (purity) |
d
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An angiodynogram shows changes in frequency content of a Doppler sample site by
a. changes in color b. changes in saturation c. changes in color texture d. the introduction of green markers |
b
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Cardiac color flow imaging shows changes in the frequency content of the Doppler sample site by
a. changes in color b. changes in saturation c. changes in color texture d. introduction of red markers |
a
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Color flow imaging systems determine the maximum Doppler shift frequency at each sample site
a. true b. false |
b
CFI = mean frequency |
|
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A measurement of the peak systolic frequency in a carotid artery with a single point spectrum will be lower than a measurement of the color-encoded frequency at the same point.
a. true b. false |
F
max systolic frequency > mean |
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T or F
The synchronous signal processing in angiodynorgraphy uses a Doppler carrier frequency that is the same as the imaging center operating frequency. |
T
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T or F
Asynchronous signal processing in color flow imaging requires the same frequency for both Doppler and gray-scale imaging. |
F
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Beam steering in asynchronous color flow imaging is used to provide
a. a Doppler angle to typical blood flow b. a way of looking at the same soft-tissue targets at an angle different from the perpendicular beams c. an enlarged Doppler beam to improve Doppler sensitivity d. improved Doppler sensitivity to smaller vessels |
a
asynchronous w/o angle= beam steering is used for typical Doppler angle |
|
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The mechanical wedge in angiodynography is used to provide
a. improved penetration through impedance matching b. improved beam focusing for the gray scale image c. an attenuation system to remove side lobes d. a Doppler angle between the typical flow patterns in vessels |
d
all Doppler requires an angle |
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The ability to see flow in deep vessels is limited by the fact that
a. blood has scattering units that are about the same size as soft tissue b. blood is moving faster than the surrounding tissues c. blood has an extremely low attenuation rate d. blood reflectivity is about 40 dB to 60dB below that of the soft tissue |
d
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T or F
Levels of output power and intensity for color flow imaging are generally higher than those for gray-scale imaging. |
T
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T or F
Because Doppler signal processing requires more energy, synchronous signal processing always produces Doppler power levels that are higher than those for gray scale imaging. |
F
synchronous = common transmitter |
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In general, tissue ultrasonic intensity levels are higher for color flow imaging with the same system.
a. True b. False |
a
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Moving from gray scale only to full color flow imaging in a system means that the image frame rate will probably
a. decrease b. increase c. stay the same |
a
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T or F
Color flow imaging in the heart uses larger Doppler sampling intervals to increase the image frame rate than does vascular imaging. |
T
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T or F
Cardiac color flow imaging also works well in the vascular system because the design can handle the high attenuation rates in cardiac imaging. |
F
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T or F
Sampling intervals for cardiac color flow imaging and vascular color flow imaging are similar. |
F
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Cardiac color flow imaging is limited with a mechanical sector scanner because
a. the cardiac attenuation rate is too high b. the ultrasound beams are always moving c. the beam has a fixed focal point d. the beam has too many side lobes |
b
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Color flow imaging and angiodynography in the peripheral vascular system typically use
a. the phased sector scan b. the linear array scan c. the curved linear scan d. a combination of A and B |
b
vascular peripheral vessels =linear array |
|
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Color flow imaging in the heart typically uses
a. the phased sector scan b. the linear array scan c. the curved linear scan d. a combination of A and C |
d
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You are imaging a small vessel using 7.5 MHz color flow imaging with the lowest portayable velocity of 6.0 cm/s. Changing only the carrier frequency to 5.0 MHz will change the lowest portrayable velocity to
a. 1.5 cm/s b. 9 cm/s c. 6.0 cm/s; the vessel does not change d. 15 cm/s |
b
lowering carrier freq= low frequency shift= low velocity portrayal |
|
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T or F
Color flow imaging is unique because it does not have a major problem with high frequency aliasing. |
F
Color flow imaging is a PW Doppler technique which is also eubject to aliasing |
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Both color and point spectrum in a stenosis show high-frequency aliasing. One strategy for removing the aliasing involves
a. doing nothing; aliasing cannot be removed from the system b. decreasing the system PRF c. decreasing the carrier frequency d. decreasing the Doppler angle towards zero |
c
low carrier frequency= low aliasing limit |
|
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Increasing output power levels and PRFs to increase penetration and frame rates opens the system to the following artifact
a. high-frequency aliasing b. loss of low velocities c. tissue mirroring d. range ambiguity |
d
HPRF, high power output = range ambiguity |
|
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T or F
The color coding of red arteries and blue veins and slow high-resolution frame rates make the identity of arteries and veins in the abdomen direct and easy |
F
abdomen= broad FOV pulse check |
|
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Turbulence in a vascular color flow image appears as
a. a mottled pattern of colors b. a mottled pattern of red and blue with changing saturation c. a mottled green region d. A and B |
d
broken streamlines |
|
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Turbulence in cardiac color flow imaging appears as
a. a mottled pattern of colors b. a mottled pattern of red and blue with changing saturations c. a bright red region d. a motlled green region |
d
spectral variance |
|
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The confirmed bioeffect(s) on pregnant women with the use of real-time diagnostic instruments is (are)
a. brain damage b. fetal developmental anomalies c. growth retardation d. no known effect |
d
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Th confirmed bioeffects on pregnant mice exposed to continuous wave ultrasound in a laboratory setting have resulted in
a. cancer b. death c. neurocranial damage d. no known effect |
c
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T or F
Viscoelasticity is the property of a medium characterized by energy distortion in the medium and irreversibly converted to heat. |
T
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T or F
Relaxation is a process of acoustic energy absorption. |
T
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T or F
Red cell stasis is an in vivo phenomenon characterized by erythrocytes within small vessels stopping the flow and collecting in the low pressure regions of the standing wave field. |
T
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Which of the following statements about bioeffects is (are) common
a. ultrasound exposure in humans is cummulative b. most harmful bioeffects that occurred in experimental conditions have been confirmed in humans in a clinical setting c. intensity, frequency and exposure time used on experimental animals were compatible to those used in a clinical setting d. continuous wave used in experimental studies gives the same tissue exposure as pulsed ultrasound used in a clinical setting e. the exposure of pregnant women to high intensity levels resulted in growth retardation of their offspring f. a and e g. all of the above are false or unconfirmed h. all of the above are true |
g
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The number of known human injuries resulting from diagnostic medical ultrasound exposure is
a. 2500 in England b. 115 in the United States c. 1500 in Japan d. no exposure injuries in humans have been reported |
d
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What is the distinction between real-time scans and B-scans?
a. no distinction, real-time scans are B-scans b. real-time scans display gray-scale images, whereas B-scans exhibit motion images c. real-time scans exhibit motion images, whereas B-scans exhibit static images d. B-scans are specific for static scanners; real-time scans are not |
a
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Transonic regions are always
a. echo-free b. anechoic c. echogenic d. uninhibited to propagation |
d
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Which of the following is not related to real-time
a. A-mode b. static imaging c. dynamic imaging d. M-mode |
b
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Which of the following combinations of frequency and intensity would most likely result in cavitation
a. high frequency and low intensity b. low frequency and high intensity c. high frequency and high intensity d. intensity has no effect in cavitation |
b
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Which of the following is not a component of the time-gain compensation (TGC) curve?
a. gray scale b. far gain c. knee d. delay |
a
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The range of pulse repetition frequencies used in diagnostic ultrasound is
a. 0.5 - 4 kHz b. 1-10 MHz c. 1-7 kHz d. 10-15 MHz |
a
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The spatial pulse length is defined as the product of the _____ multiplied by the number of ____ in a pulse.
a. cycles, frequency b. frequency, velocity c. wavelength, cycles d. frequency, wavelength |
c
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Which of the following is (are) one-dimensional?
a. B-mode and A-mode b. A-mode and M-mode c. B-mode d. static imaging |
b
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Continuous wave ultrasound is
a. applicable to real-time instruments only b. used in all Doppler instruments c. used in some Doppler instruments d. applicable only to static scanners |
c
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Which imaging modality is audible
a. x-ray b. ultrasound c. Doppler d. CT scan |
c
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Which mode requires two crystals, one for transmitting and one for receiving?
a. A-mode b. M-mode c. continuous wave mode d. pulse-echo mode |
c
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The normal range of intensities used in Doppler instruments is
a. 0.2 - 400 W/cm2 b. 0.2-400 mW/cm2 c. 400-800 mW/cm2 d. 800-900 mW/cm2 |
b
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If the media boundary is moving toward the source, the reflected sound wave will have
a. a higher frequency than the incident frequency b. a lower frequency than the incident frequency c. no change in frequency d. be delayed |
a
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If the media boundary is moving away from the source, the result will be
a. a higher frequency than the incident frequency b. a lower frequency than the incident frequency c. no change in frequency d. be delayed |
b
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A Doppler instrument that can distinguish between positive and negative shifts is called
a. bistable b. a modulator-demodulator c. bidirectional d. a polarized shifter |
c
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Which statement about Doppler application is not true?
a. color Doppler is not beneficial b. Doppler can produce audible sound c. Doppler instruments use both pulsed and continuous wave d. Doppler can display an image |
a
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The range of frequencies contained in an ultrasound pulse is called
a. propagation b. bandwidth c. refraction d. rejection |
b
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Which quantity is unitless
a. Q-factor b. volume c. intensity d. force |
a
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Which of the following would most likely cause acoustic enhancement?
a. a solid mass b. a fluid filled mass c. a calcified mass d. a gallstone |
b
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Which of the following would most likely cause acoustic shadowing?
a. a gallbladder b. a fluid-filled mass c. a calcified mass d. urinary bladder |
c
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Continuous Doppler uses how many piezoelectric elements?
a. 1 b. 2 c. 64 d. none |
b
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The greatest Doppler angle is achieved
a. when the beam strikes a vessel at a sharp angle b. when the beam strikes a vessel perpendicular c. when the beam strikes a vessel at a 30 degree angle d. when the beam strikes a vessel at a 70 degree angle |
b
90 degree/perpendicular= no Doppler shift |
|
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|
If the power output of an amplifier is 100 times the power at the input, the gain is
a. 10 dB b. 20 dB c. 30 dB d. 40 dB |
b
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Which control is used to minimize the effects of attenuation?
a. reject b. filed-of-view c. frame rate d. depth gain compensation |
d
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When an ultrasound beam passes obliquely across the boundary between two materials, ______ will occur if there is a difference in _____ in the two materials
a. reflection, impedance b. reflection, density c. refraction, impedance d. refraction, propagation speed |
d
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A decreased pulse duration leads to
a. better axial resolution b. decreased spatial resolution c. decreased longitudinal resolution d. a better lateral resolution |
a
damping |
|
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What is the reflected intensity from a boundary between two materials if the incident intensity is 1 mW/cm2 and impedance are 25 and 75?
a. 0.25 mW/cm2 b. 0.33 mW/cm2 c. 0.50 mW/cm2 d. 1.0 mW/cm2 |
a
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The near zone length of an unfocused transducer depends on
a. frequency and thickness b. frequency and diameter c. resolution and field of view d. diameter and field of view |
b
NZL = D squared/ 4 x wavelength |
|
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|
The frequency of a transducer primarily depends on
a. overall gain b. the speed of ultrasound c. the element diameter d. the element thickness |
d
thickness = 1/2 wavelength |
|
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|
An ultrasound beam that is normally incident on an interface will experience no
a. attenuation b. refraction c. reflection d. absorption |
b
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|
The average speed of propagation of ultrasound in soft tissue
a. 1.540 ft/s b. 1.54 dB/cm c. 1.54 mm/us d. 1540 mW/cm2 |
c
1540 m/s |
|
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|
The duty factor for a system with a pulse duaration of 5 us and a pulse repetition period of 500 us is
a. 0.1 % b. 0.5 % c. 1.0 % d. 10% |
c
PD/ PRP x 100 |
|
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|
Ultrasound is defined a sound with frequencies above
a. 20 Hz b. 20 kHz c. 20 MHz d. 20 GHz |
b
>20,000 Hz or 20kHz or 0.2 MHz |
|
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|
Frequency is a significant factor in
a. propagation speed b. tissue compressibility c. tissue attenuation d. transducer diameter |
c
attenuation coefficient is 0.5 dB/cm/ MHz |
|
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|
In a pulse-echo system,a 3.5 MHz beam in 2 cm of tissue will be attenuated by
a. 3.5 dB/cm b. 7.0 dB/cm c. 3.5 dB d. 7.0 dB |
c
atten coefficient is (3.5 x 0.5) atten= atten coeff x path length |
|
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|
The characteristic acoustic impedance of a material is equal to the product of the material density and
a. path length b. wavelength c. frequency d. propagation speed |
d
|
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|
For a focused transducer,the beam intensity will remain constant through the scan field
a. true b. false |
b
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|
For normal incidence,if the intensity reflection coeeficient is 30%, the intensity transmission coefficient will be
a. 30% b. 60% c. 70% d. 100% |
c
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|
A Fourier transform of a returning echo will result in a presentation of the _____ contained within the echo
a. frequencies b. wavelength c. intensity d. power |
a
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|
The range equation relates
a. frequency, velocity and wavelength b. frequency, velocity and time c. distance, velocity and time d. distance, frequency and time |
c
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|
The axial resolution of a system is determined by
a. spatial pulse length b. beam intensity c. beam diameter d. spatial resolution |
a
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|
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|
The Doppler shift frequency is zero when the angle between the receiving transducer and the flow direction is
(all in degrees) a. 0 b. 45 c. 90 d. 180 |
c
Doppler shift is proportional to the cos of angle |
|
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|
The frame rate of real-time scanner that uses an electronic array will be limited only by the speed of the scan converter memory
a. true b. false |
b
pulses per scan line, PRF, depth of view |
|
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|
The dynamic range of a pulse-echo ultrasound system is defined as
a. the ratio of the maximum to the minimum intensity that can be processed b. the range of propagation speeds c. the range of gain settings allowed d. none of the above |
a
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|
|
|
The digital scan converter will generally have a dynamic range that is ______ than the other components of the system.
a. larger b. smaller |
b
bit depth |
|
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|
The time-gain or depth-gain compensation control
a. compensates for attenuation effects b. compensates for increased patient scan time c. compensates for machine malfunctions d. compensates for vide-image drifts |
a
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|
A digital scan converter is essentially a
a. radio receiver b. video monitor c. television set d. computer memory |
d
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|
A mechanical real-time scanner will always produce images at a slower frame rate than does an electronic real time scanner
a. true b. false |
b
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|
Acoustic enhancement can be observed when scanning
a. highly attenuating structure b. weakly attenuating structure c. highly reflective structure d. structures with high speed differences |
b
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|
T or F
Changes in the pre processing controls will not affect the numbers stored in the scan converter. |
F
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|
The lateral resolution of a system
a. is equal to the beam diameter b. is better at higher frequencies c. is constant throughout the image d. changes with gain settings |
a
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If the lines per degree in a mechanical sector scanner remain constant, a decreased sector angle can result in
a. decreased resolution b. increased frame rate c. decreased frame rate d. increased resolution |
b
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The threshold control is equivalent to the
a. TGC control b. DGC control c. modulation control d. reject control |
d
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If the actual speed in soft tissue is 1700 m/s, current diagnostic scanners will display a reflector at a location ________ the transducer.
a. too close to b. too far from c. displaced to the left of d. displaced to the right of |
a
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CW ultrasound is used in
a. static B-scanners b. bistable systems c. most modern B-scan system d. some Doppler systems |
d
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If the gain of an amplifier is 18 dB, what will the new gain setting be if one reduces the gain setting by one-half?
a. 9 dB b. 36 dB c. 15 dB d. 0.5 dB |
c
every 3dB change the intensity will change by factor 2 |
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Decreasing the pulse repetition period
a. decreases spatial resolution b. decreases axial resolution c. decreases the maximum depth image d. increases the maximum depth image |
c
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A AIUM 100-mm test object
a. measures power output b. measures beam intensity c. measures frequency d. measures spatial resolution |
d
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Real-time imaging impossible without electronic arrays
a. true b. false |
b
Mechanical steering of single element transducer |
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Grating lobes in electronic array systems
a. increased with increased steering angle b. decreased with increased steering angle c. are eliminated at high frame rates d. are not likely ro produce artifacts |
a
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The attenuation coefficient is expressed in units of
a. mW/cm2 b. dB c. dB/cm d. mW |
c
total attnuation = dB |
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The wave equation relates
a. time, mass and distance b. time, velocity, and frequency c. wavelength, velocity, and frequency d. wavelength, distance and frequency |
c
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The ability of a system to detect low-amplitude echoes accurately is referred to as
a. resolution b. sensitivity c. accuracy d. dynamic range |
b
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The primary mechanisms whereby ultrasound can produce biologic effects are
a. thermal and cavitation b. absorption and reflection c. reflection and transmission d. heat and cold |
a
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The NZL of a transducer depends on
a. propagation speed and frequency b. frequency and transducer diameter c. field of view and transducer diameter d. path length |
b
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The AIUM Committee on Biological Effects (1982) stated that ____ biologic effects have been observed for ultrasound intensities below 100 mW/cm2
a. no b. no confirmed c. few d. many |
b
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The intensity of a focused beam is generally
a. constant b. highest at the transducer surface c. highest at the focal zone d. lowest at the transducer surface |
c
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The wavelength of a 5 MHz wave passing through soft tissue is approximately
a. 0.1 mm b. 0.3 mm c. 0.5 mm d. 1.0 mm |
b
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T or F
The pulse-echo system should have a high Q factor. |
F
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A 5 MHz transducer used in pulse echo system will generally produce
a. a wide band of frequencies centered at 5 MHz b. frequencies only at 5 MHz c. frequencies only at 5 MHz or multiples of 5 MHz d. a wide band of frequencies above 5 MHz |
a
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The transducer ____ determines its ______.
a. diameter, intensity b. damping, lateral resolution c. thickness, sensitivity d. thickness, resonance frequency |
d
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An echo that has undergone an attenuation of 3 dB will have an intensity that is ____ than its initial intensity.
a. three time smaller b. three time larger c. two times smaller d. two times larger |
c
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The axial resolution of a transducer can be improved with _____ but at the expense of ______.
a. increased damping, sensitivity b. frequency, lateral resolution c. focusing, sensitivity d. focusing, lateral resolution |
a
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A material that changes its dimensions when an electric field is applied is called ____ material.
a. piezoelectric b. eleastic c. inelastic d. compressible |
a
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The process of making the impedance values on either side of a boundary as close as possible to reduce reflections is called
a. damping b. refracting c. matching d. compensating |
c
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The pressure peaks of two waves coincide at a point to produce a new pressure that is larger than either of the two initial waves, the effect is called
a. phase cancellation b. destructive interference c. enhancement d. constructive interference |
d
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Shadowing occurs with
a. highly attenuating structures b. large changes in propagation speeds c. low frequencies more often than with high frequencies d. weak reflectors |
a
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Reverberation artifacts
a. occur most often at high frequencies b. occur with multiple strong reflecting structures c. occur only with real-time arrays d. cannot occur in color Doppler systems |
b
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A transducer with a large bandwidth is likely to have
a. good axial resolution b. a large ring down time c. poor resolution d. a high Q factor |
a
large bandwidth = short SPL= low Q |
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The near zone is also referred to as the
a. Fraunhofer zone b. Fresnel zone c. focal zone d. divergence zone |
b
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Refraction will not occur at an interface
a. when high frequencies are used b. if the acoustic impedances are equal c. if the propagation speeds are significantly different d. with normal incidence of the ultrasound beam |
d
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Acoustic power output is determined primarily by
a. the diameter of the transducer b. the thickness of the transducer c. the pulser voltage spike d. focusing |
c
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Specular reflections occur when
a. the reflecting object is small with respect to the wavelength b. the reflecting surface is large and smooth with respect to the wavelength c. the reflecting objects are moving d. the angle of incidence and angle of reflection are unequal |
b
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The angle at which an ultrasound beam is bent as it passes through a boundary between two different materials is described mathematically by
a. Huygen's principle b. Curie's principle c. Snell's law d. Doppler's law |
c
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An annular array real-time scanner
a. is steered electronically b. is steered mechanically c. is not capable of electronic focusing d. is not used with digital scan converters |
b
annular array unable to electronically steer |
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The percentage of an ultrasound beam reflected at an interface between gas and soft tissue is approximately
a. 90-100% b. 40-50% c. 1-10% d. 0% |
a
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The percentage of an ultrasound beam reflected at an interface between fat and muscle is approximately
a. 90-100% b 40-50% c. 1-10% d. 0 |
c
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By using a waterpath offset,
a. tissue attenuation can be reduced b. the focal zone can be moved to the skin surface c. lower frequencies can be used d. longitudinal compression waves |
b
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Ultrasound waves in tissue are referred to as
a. shear waves b. transverse waves c. vibrational waves d. longitudinal waves |
d
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High frequency transducers have
a. shorter wavelengths and less penetration b. longer wavelengths greater penetration c. shorter wavelengths and greater penetration d. longer wavelengths and less penetration |
a
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When the piezoelectric crystal continues to vibrate after the initial voltage pulse, this referred to as
a. ring-down time b. pulse delay c. pulse retardation d. overdamping |
a
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Annular phased arrays unlike linear phased arrays
a. can be dynamically focused b. electronically focus in two dimensions rather than one c. an be used in Doppler systems d. can achieve hih frame rate |
b
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Which group is arranged in the correct order of increasing propagation speed?
a. gas, bone, muscle b. bone, muscle, gas c. gas, muscle, bone d. musce, bone, gas |
c
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The lower useful range of diagnostic ultrasound is determined primarily by ___, whereas the upper useful range is determined by _____.
a. resolution, penetration b. scattering, propagation speed c. cost, resolution d. scattering, resolution |
a
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T or F
Color Doppler systems are not subject to aliasing. |
F
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Which of the following is true?
a. SPTA is always equal to or greater than SPTP b. SPTP is always equal to or greater than SPTA c. SATA is always equal to or greater than SPTA d. SPTA is always equal to or greater than SATP |
b
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The beam-intensity profile is often mapped with
a. radiation force balance b. a SUAR phantom c. a hydrophone d. AIUM phantom |
c
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Real-time scanners are generally classified as either
a. electronic or mechanical b. dynamic or fixed c. programable or fixed d. static or electronic |
a
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The technique of passing an ultrasound beam through water so that compression and rarefraction of the water molecules allow the beam pattern to be measured is referred to as the
a. Doppler method b. Schlieren method c. hydrostatic method d. water-density method |
b
Photography gives 2 D photograph of the beam pressure profile |
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Pulse duration is the ___ for a pulse to occur
a. space b. range c. intensity d. time |
d
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The frame rate of a real-time scanner will not depend on
a. the depth of view b. the line density c. the frequency d. the propagation speed |
c
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The unit of measure of SPTA
a. dB b. W/cm2 c. W d. Hz |
b
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The piezoelectric properties of a transducer will be lost if the crystal is heated above the
a. dew point b. dynamic range c. Curie point d. linear range |
c
573 degree C for quartz PET-4 328 deg C |
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If the amplitude of a wave is increased threefold, the intensity will
a. decrease threefold b. increase threefold c. increase ninefold d. increase sixfold |
c
I = A^2/area |
|
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T or F
A videotape recorder records at a rate of 30 frames/s and therefore cannot be used to record images from a mechanical scanner operating at lower frame rates. |
F
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If the frequency is increased, the ____ will be ______.
a. velocity, increased b. attenuation, decreased c. velocity, decreased d. velocity, unchanged |
d
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Beam steering is achieved in a linear phased array by
a. mechanical motion b. elecronic time-delay pulsing c. an acoustic lens d. dynamic focusing |
b
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Dynamic focusing
a. is made possible by array-based sytems b. is made possible by acoustic lens c. is not possible in a linear-switched array d. is often used in single-element systems |
a
dynamic focusing = array systems |
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T or F
Quality assurance measurements are not required with electronic scanners with digital scan converters |
F
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Sound will travel _____ in 1 us in soft tissue
a. 1540 m b. 1.54 cm c. 1.54 mm d. 0.75 mm |
c
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T or F
The period of an ultrasound wave is related to the frequency and is the same regardless whether the wave is pulse or continuous. |
T
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Which measure of intensity is related most closely to tissue heating?
a. Im b. SATA c. SPPA d. SPTA e. SPTP |
D
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Which component of an ultrasound system is most likely to expose a patient to danger?
a. CRT b. transducer c. scan converter d. pulser |
b
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What is the hydrostatic pressure in arteries above the heart level, BP of patient standing is 140 mmHg?
a. (-) 100 mmHg b. (+) 30 mmHg c. (-) 30 mmHg d. (+) 50 mmHg |
C
head (-) sign |
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A reduction in the intensity of a sound beam to one-half of its original value is ______ dB.
a. -3 dB b. -6 dB c. -10 dB |
a
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-10 dB means that the intensity is reduced to ______. of its original value.
|
one-tenth
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dB is a mathematical representation with a ________ scale
a. logarithmic and relative b. division and relative c. longitudinal and relative d. logarithmic and absolute |
a
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True or False.
We need one intensity to calculate decibel. |
False
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A wave's intensity is 2 mW/cm2. There is a change of +9 dB. What is the final intensity?
a. 6 mW/cm3 b. 2 mW/cm2 c. 16 mW/cm2 d. 16uW/cm2 |
c
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Attenuation in lung tissue is (less than, greater than, the same as) attenuation in soft tissue.
|
greater than
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In a given medium, attenuation is unrelated to speed of sound.
T or F |
True
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As the path length increases, the half boundary layer _____.
a. increases b. decreases c. remains the same |
c
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Impedance is a characteristic of _____.
a. sound b. medium c. ultrasound system |
b
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As the path length increases, the attenuation coefficient of ultrasound in soft tissue
a. increases b. decreased c. remains the same |
c
atten coefficient depends on frequency only (0.5 dB/MHz) |
|
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What is the shape of the elements in an annular phased array transducer?
a. rectangles b. squares c. wedges d. circles |
d
donut or ring shaped |
|
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Which best describes the elements in a linear phased array transducer?
a. rectangular, 1/4 wavelength thick b. rectangular, 1/2 to 1/4 wavelength wide c. circular d. squares, 1 wavelength thick |
b
( rectangular for linear phased, wide) |
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Which best describes the elements in a linear sequential array transducer?
a. rectangular, 1/4 wavelength thick b. rectangular, 1/4 to 1/2 wavelength wide c. rectangular, 1 wavelength wide d. squares, 1 wavelength thick |
b
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What is created with a two-dimensional array transducer?
a. two-dimensional static image b. two-dimensional real time image c. static B-mode d. A-mode |
b
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While using a linear sequential array transducer during a color Doppler exam, the shape of the grayscale image is most often _________, whereas the shape of the color Doppler portion of the image is ______.
a. rectangular, parallelogram b. rectangular, sector c. sector, trapezoid d. square, rectangular |
a
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T or F
An ultrasound system with a shorter PRP will have better temporal resolution than a system with longer PRP. |
T
due to the ability to produce more pulses each second |
|
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What two factors determine a system's temporal resolution?
a. speed of sound and depth of view b. pixel size and sector size c. focal zones and sector depth d. propagation speed and frame rate |
a
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Which two controls determine a system's temporal resolution?
a. frame rate and sector size b. focal zones and sector depth c. propagation speed and frame rate d. depth of view and pulses per image |
d
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Which of the following sector imaging system's will have the best image detail if all other parameters are identical?
a. a 90 degree sector with 100 pulse/image b. an 80 degree sector with 40 pulses/image c. a 70 degree sector with 84 pulses per image d. a 60 degree sector with 60 pulses/ image |
c
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Of the following, which imaging modality has the poorest temporal resolution?
a. two-dimensional, real time b. A-mode c. color flow imaging d. M-mode |
c
many pulses are required to create a single color flow image |
|
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All of the following reduce temporal resolution by increasing the number of pulses per image, except
a. increasing the number of foci b. increasing line density c. increasing field of view d..increasing depth of view |
d
depth= by changing the PRP not by increasing the number of pulses/image |
|
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What is the primary reason why blood moves from one location to another?
a. energy gradient b. anemia c. pressure gradient c. systole d. friction |
a
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What is coaptation?
a. vessel collapse b. blood clotting c. Bernoulli's flow d. capillary filtration |
a
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The arterial blood pressure of a supine individual is 120 mmHg. What is the hydrostatic pressure at the subjects's ankle?
a. 100 mmHg b. 0 mmHg c. 40 mmHg d. 120 mmHg e. -120 mmHg |
b
(supine) |
|
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The arterial blood pressure of a supine individual is 120 mmHg. What is the hydrostatic pressure at the subjects's hips?
a. 120 mmHg b. 75 mmHg c. -30 mmHg d. 0 mmHg |
d
supine |
|
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The arterial blood pressure of a standing individual is 120 mmHg. What is the hydrostatic pressure at the subjects's ankle?
a. 100 mmHg b. 0 mmHg c. 40 mmHg d. -100 mmHg e. -120 mmmHg |
a
(standing) knee=75 mmHg waist= 40 mmHg top of head = -30 mmHg |
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The arterial blood pressure of a standing individual is 120 mmHg at the level of the heart. What is the measured blood pressure at the subjects's ankle?
a. 100 mmHg b. 0 mmHg c. 40 mmHg d. -100 mmHg e. 220 mmmHg |
e
(standing ankle hydrostatic 100 mmHg + 120 mmHg) = 220 mmHg |
|
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What happens to the venous flow inthe legs when an individual inhales?
a. increases b. decreases c. remains the same |
b
exhales= legs venous return increases something to do with intrathoracic pressure and movement of diaphragm during inspiration |
|
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|
In standard Doppler, what is true about the reflected frequency produced by blood cells traveling in a direction away from the transducer?
a. it is in audible range b. it is ultrasonic c. it exceeds the transmitted frequency d. it equals the transmitted frequency |
b
low frequency but inaudible > 20kHz (audible >20kHz) |
|
|
|
T or F
The appearance of negative velocities in a pulsed Doppler display always indicates that red blood cells are moving away from the transducer. |
F
aliasing may occur |
|
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What is a typical pulser output voltage that excites a piezoelectric crystal?
a. 0.1 volts b. 500 millivolts c. 110 volts d. 10 microvolts |
c
?typical voltage for some electronic devices |
|
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|
What is the typical voltage of the signal that is the input to the receiver of an ultrasound system?
a. 0.1 volts b. 500 mvolts c. 250 volts d. 10 uvolts |
d
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|
Which of the following does not belong in th group below?
a. receiver gain b. energy oupput c. pulse power d. acosutic power e. transmitter output f. output gain |
a
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Which one of these functions are performed by the receiver of an ultrasound system? (more than one answer may be correct)
a. amplification b. threshold c. compensation d. demodulation |
a, b,c d
|
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Which of the following actions will improve signal to noise ratio?
a. increase dynamic range b. increase receiver gain c. increase output power d. increase TGC |
c
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|
T or F
The sonographer can make an image of uniform brightness by adjusting both output power and receiver gain. |
F
TGC can |
|
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What is the process of adjusting for path length related attenuation called?
a. compression b. compensation c. GTC d. reconfirmation |
b
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Which transducer system is most likely to have the longest delay in its TGC curve?
a. a 5 MHz linear array b. a 2.5 MHz annular array c. a 7.5 MHz mechanical d. a 5 MHz annular |
b
low freq transducer has less attenuation |
|
|
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At which imaging depth is the slope of the TGC curve most effective?
a. the region very close to the transducer b. the far zone c. the focal zone |
c
|
|
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|
T or F
Typically, the sonographer can adjust the compression function of a receiver. |
T
|
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A signal with a 120 dB dynamic range is compressed by 40 dB. Wha is the dynamic range of the compressed signal?
a. 40 dB b. 120 dB c. 3 dB d. 80 dB |
d
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|
The process of eliminating low amplitude signals from further processing is called all of the following except _______.
a. reject b. subordination c. threshold d. suppression |
b
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|
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|
T or F
The sonographer can adjust the threshold level. |
T
also called reject |
|
|
|
A signal is increased from 1 mvolt to 1 volt by the amplifier. How many decibels is this?
a. 1000 dB b. 20 dB c. 40 dB d. 60 dB e. 100 dB |
d
for voltages (each 0 is =20 dB) 1000-fold increase = 60dB 100 = 40 dB 10 = 20 dB |
|
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|
How does a cathode ray tube steer the charged particles emitted by the electron gun, located at the back of the tube, so that they sweep across the front screen?
a. by phasing the source b. by mechanically steering the gun c. by sending them through a time-varying magnetic field d. by reflecting the particles off of a mirrored surface |
c
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|
a standard television system processes information rapidly to provide the viewer with the sensation of a real-time display. How is this achieved?
a. 60 frames/sec in sequence b. alternate frames at a rate of 30/sec c. alternate even and odd fields at a rate of 60/sec d. even and odd fields at a rate of 60/sec |
c
|
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|
A byte is composed of _____ bits. A word is composed of _____ bytes.
a. 2, 2 b. 8, 2 c. 16, 16 d. 8, 16 |
b
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|
Ultrasound systems are designed to automatically _________.
a. display similar structures with equal brightness, regardless of depth b. position structures at the correct depth, regardless of the medium c. display all reflections on a line corresponding to the main axis of the sound beam, regardless of refraction d. select the optimal beam width based on clinical application |
c
|
|
|
|
With depth resolution
a. too many reflectors appear on the image b. reflectors are placed too deep on the image c. too few reflectors are on the image d. reflectors appear too shallow on the image |
c
|
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|
|
With which of the following pulses would lateral resolution be worst?
a. 10 MHz, 4 mm beam diameter, 4 cycles per pulse b. 4 MHz, 4 mm beam diameter, 2 cycles per pulse c. 7.5 MHz, 8 mm beam diameter, 2 cycles per pulse d. 6 MHz, 2 mm beam diameter, 2 cycles per pulse |
c
wide beam diameter = high numeric value for lateral resolution (poor resolution) |
|
|
|
What is the cause of acoustic speckle?
a. refraction b. attenuation c. interference of tiny acoustic wavelets d. resonance of particles in the near filed |
c
|
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|
|
Which artifact results in improper side-byside positioning of reflectors?
a. multipath b. comet tail c. refraction d. reverberation |
c
|
|
|
|
Which process cause the mirror image artifact?
a. reflection b. refraction c. propagation speed error d. attenuation |
a
|
|
|
|
What is comet tail artifact's fundamental mechanism of formation?
a. reflection b. rarefraction c. refraction d. attenuation |
a
numerous reflection between two closely spaced reflectors |
|
|
|
In diagnostic imaging, how does multipath artifact affect the image?
a. poor angular resolution b. creation of hyperechoic regions c. mild image degradation d. gross horizaontal misregistration |
c
|
|
|
|
Grating lobes are most common wit which type of transducr technology?
a. annular array b. continuous wave c. mechanical scanners d. linear arrays |
d
|
|
|
|
Acoustic focusing of an ultrasound beam may create which artifact?
a. side lobes b.refraction c. speckle d. enhancement |
d
focal enhancement |
|
|
|
T or F
Side lobe, grating lobe and refraction artifacts all reduce lateral resolution. |
T
|
|
|
|
Which two of the following devices convert ultrasound energy into heat?
a. calorimeter b. thermocouple c. hydrophone d. Schlieren |
a and b
thermocouple is specific region calorimeter whole beam area |
|
|
|
The ______measures beam intensity at specific locations, whereas a ____ measures the entire energy in a sound beam
a. calorimeter, thermocouple b. Schlieren, thermocouple c. thermocouple, calorimeter d. thermocouple, hydrometer |
C
|
|
|
|
Which of the following is not a potential mechanism for production of bioeffects from ultrasound exposure to the body?
a. temperature elevation b. fractionation c. cavitation d. vibration |
b
|
|
|
|
Which selection has the highest mechanical index?
a. high frequency, high power b. high PRF, high intensity c. low frequency, high pressure d. high spatial pulse length, high PRF |
c
|
|
|
|
Whic sound wave is least likely to create cavitation?
a. 5 MHz. 2 MPa b. 2 MHZ, 4 MPa c. 6 MHz, 2 MPa d. 2 MHz, 2 MPa |
c
|
|
|
|
Which of the following epidemiologic studies considered most likely to produce meaningful results?
a. retrospective and prospective b. prospective and randomized c. restrospective and empirical d. prospective and mechanistic |
b
|
|
|
|
Which component of an ultrasound system exposes a patient to greatest risk?
a. the CRT b. the electric cord c. the pulser d. the transducer |
d
|
|
|
|
T or F
Artifacts are likely to appear when the dimensions of the sound beam area are larger than the dimensions of the reflectors in the body. |
T
|
|
|
|
T or F
Quality assurance evaluations of ultrasound systems should be performed weekly. |
F
routinely |
|
|
|
According to AIUM, at what in situ tissue temperature is there a danger to fetus?
a. 100 degree C b. 98.6 degree F c. 1 degree F over normal temp d. 41 degree celsius |
d
|
|
|
|
Which of the following ultrasound beams has a characteristic that is most likely to cause temperature elevation in soft tissue?
a. strongly focused b. medium focused c. unfocused |
c
due to broad area over which beam spreads |
|
|
|
Transducer assemblies are also called ________.
a. transducer b. probes c. scanheads d. scan converters e. skinheads f. more than one of the above |
f (a, b,c)
|
|
|
|
Mixture of piezoelectric ceramic and non piezoelectric polymer are called
a. PVDFs b. cMUTs c. composite d. compound material |
c
|
|
|
|
Is it practical to attempt to operate a 5 MHz transducer with a bandwidth of 1 MHz at 6 MHz?
|
No
Bandwidth/2 = +/- op freq |
|
|
|
Is it practical to attempt to operate a 5 MHz transducer with a bandwidth of 2.5 MHz at 3 MHz and 7 MHz?
|
No
|
|
|
|
Transducer size is also called
a. axial resolution b. aperture c. bandwidth d. lateral resolution |
b
|
|
|
|
If the elements of a phased array are pulsed in rapid succession from right to left, the resulting beam is
a. steered right b. steered left c. focused |
b
|
|
|
|
If elements of a phased array are pulsed in rapid succession from outside in, the resulting beam is
a. steered right b. steered left c. focused |
c
|
|
|
|
_____ and _______ describe how arrays are operated.
a. linear b. phased c. sequenced d. vector e. convex |
a,e
|
|
|
|
Shorter time delays between elements fired from outside in results in _____ curvature in the emitted pulse and a ______ focus.
a. no, weak b. less, shallower c. less, deeper d. greater, shallower e. greater, deeper |
c
short time= less, shallow focus |
|
|
|
______, _________, and _______ describe how arrays are operated.
a. linear b. phased c. sequenced d. vector e. convex |
b,c,d
|
|
|
|
Length of time it takes to complete a single cycle
|
Period
|
f= 1/T, s, ms, us
|
|
|
Number of cycles in a specific time; reciprocal of Period
|
Frequency
|
c/s, Hertz, kHz, MHz
|
|
|
Maximum variation in an acoustic variable
|
Amplitude
|
any units of the acoustic variable
|
|
|
The difference between the average value and the maximum value of the acoustic variable
|
Amplitude
|
|
|
|
Squared amplitude; Proportional to Intensity
|
Power
|
Watts
|
|
|
Power divided by the cross sectional area of the beam
|
Intensity
|
Watts/cm2
|
|
|
Audible Frequency
|
20 Hz - 20kHz
|
|
|
|
Ultrasonic Frequency
|
> 20 kHz
|
Clinical setting: 2-10 MHz
|
|
|
Creation of low-pressure region in sound propagation
|
Rarefaction
|
|
|
|
Creation of high pressure region
|
Compression
|
|
|
|
Length of one complete wave cycle
|
Wavelength
|
m, cm, mm
|
|
|
Speed at which the wave propagates through a medium
|
acoustic Velocity (c)
|
|
|
|
In determining the acoustic velocity which one is the key factor? Compressibility or Density
|
Compressibility
|
Density alone; if density increase, speed decrease
|
|
|
T or F
Temperature also affect the speed of ultrasound in tissues. |
True
|
1540 degress 37 degree
1480 degrees 20 degree water temp |
|
|
T or F
The velocity of sound or ultrasound remains constant for a particular medium. |
True
|
|
|
|
On the basis of density comparison alone, one would expect the velocity in a solid substance to be greater than the velocity in a liquid.Assume the solid is more dense than the liquid.
|
False
|
D opp S
|
|
|
On the basis of compressibility comparison alone, one would expect the velocity in a solid substance to be greater than the velocity in a liquid.
|
True
|
|
|
|
A-mode scanning represents the amplitude of the signal in one dimension and the depth of the echo in the other dimension.
|
True
|
|
|
|
Real time imaging produces a single image each second.
|
False
|
|
|
|
Transmission scanning relies on the principle of echo-ranging.
|
False
|
|
|
|
Doppler mode scanning detects relative motion between the sound source and the reflecting interface.
|
True
|
|
|
|
The piezoelectric property permits the use of transducer as a receiver of sound.
|
True
|
|
|
|
Crystal thickness determines the center frequency of the transducer.
|
True
|
|
|
|
The Z of the backing material in a A-mode or B=mode transducer is nearly the same as the Z of the crystal
|
True
|
|
|
|
Assume the acoustic impedances are not equal for two materials composing the interface. Refraction occurs is a beam strikes the interface at 30 degree incidence.
|
False
|
V1>V2, bent towards
|
|
|
The transfer of ultrasound energy to the tissure during propagation
|
Absorption
|
|
|
|
The product of the density of the medium and the velocity of sound
|
Acoustic impedance
|
|
|
|
The magnitude of the pressure changes along the wave, the strength of the waves
|
Amplitude
|
|
|
|
The net loss of ultrasound energy as a wave propagates through a medium
|
Attenuation
|
|
|
|
The combination or sum of 1 compression and 1 rarefraction of a propagating wave
|
Cycle
|
|
|
|
The time in beween pulses that the echograph is not emitting ultrasound
|
Dead time
|
'Off-time"
|
|
|
A logarithmic measure of the intensity of of sound, expressed as a ration to a reference value
|
Decibel
|
|
|
|
The fraction of time that the transducer is emitting US, a unitless number bet 0 and 1
|
Duty Factor
|
|
|
|
The diverging conical portion of the beam beyond the near field
|
Far field
|
|
|
|
The number of cycles per second
|
Frequency
|
Hz, C/s
|
|
|
The distance an ultrasound beam penetrates into a medium before its intensity has attenuated to one-half of the original value.
|
Half-value layer
|
|
|
|
The concentration or distribution of power within an area (cross-sectional area) of the beam
|
Intensity
|
|
|
|
A cyclic disturbance in which the energy propagation is parallel to the direction of the particle motion
|
Longitudinal Wave
|
|
|
|
The proximal cylindrical-shaped portion of the US beam before divergence begin to occur
|
Near Field (Fresner Zone)
|
|
|
|
The time required to complete 1 cycle
|
Period
|
|
|
|
The rate of transfer over time of the acoustic energy from the propagating wave to the medium
|
Power
|
Watts
|
|
|
A burst or packet of emitted US of finite duration, containing a fixed number of cycles travelling together
|
Pulse
|
|
|
|
Length or distance of a pulse occupied in space
|
Pulse length
|
|
|
|
The rate at which pulses are emitted from the transducer
|
Pulse repetition frequency
|
|
|
|
The smallest distance between 2 points that allows the points to be distinguished as separate
|
resolution
|
|
|
|
T or F
The velocity of ultrasound is directly proportional to he compressibility of the medium. |
False
|
Stiffness, Speed
same S Compressibility is opposite of stiffness |
|
|
T or F
Density of the medium is directly proportional to the speed of ultrasound. |
False
|
D and S opposite
|
|
|
T or F
The angle of reflection is equal to the angle of incidence. |
True
|
right angles, normal incidence
|
|
|
T or F
The wavelength is directly proportional to the frequency. |
False
|
C = fλ
|
|
|
T or F
The velocity (c) is directly proportional to the wavelength and frequency. |
True
|
C = fλ
|
|
|
T or F
The higher the frequency, the deeper the penetration of the beam. |
False
|
Frequency and wavelength are inversely proportional.
|
|
|
True or False
Diffraction is the only process whereby sound is dissipated in the medium. |
False
|
Difraction = diverge
|
|
|
T or F
Constructive interference is the superposition of waves that are in phase. |
True
|
|
|
|
T or F
Complete destructive interference occurs when waves are of the same frequency and amplitude and are completely out of phase. |
True
|
|
|
|
T or F
Absorption is the process whereby ultrasonic energy is transformed into other forms of energy, primarily heat and are used mainly for therapeutic purposes. |
True
|
|
|
|
Absorption of the ultrasonic beam is related to the following, except:
A.frequency of the beam B.angle of incidence C.viscosity of the medium D.relaxation time of the medium |
B
|
|
|
|
T or F
Refraction depends on the difference in acoustic impedances of the media forming the interface. |
False
depends on the propagation speed differences in the medium and oblique angle of incident |
|
|
|
T or F
The period of the wave is directly proportional to the frequency of the wave. |
False
|
P = 1/f
|
|
|
T or F
Ultrasound waves are mechanical and longitudinal waves. |
True
|
|
|
|
T or F
Ultrasound waves are transverse and electromagnetic in nature. |
False
|
|
|
|
The only technique that does not rely on echo ranging principle.
A. Real time imaging B. Sonar navigation C. Transmission mode scanning D. A-mode scanning |
C
|
|
|
|
The following are static imaging principles, except:
A. Transmission mode scanning B. A-Mode scanning C. B-mode imaging D. 2-Dimensional imaging |
D
|
|
|
|
Which of the following statements regarding A-mode imaging is/are true?
A. It is based on the echo-ranging principles. B. Displays the magnitude of signal as a spike in one dimension, Y, versus the depth or time of the signal in the other dimension. C. Used in echoencephalography for detection of midline shift and for localization of foreign bodies in the eye. C. All of the above |
D
|
|
|
|
Initiates the scanning process by commanding the transmitter to send voltage pulse to the transducer
A. CRT B. Master synchoronizer C. Registration arm D. Time base sweep control |
B
|
|
|
|
The sweep rate in tissue
A. 1 mm every 13 us B. 13 mm every 1 us C. 1 cm every 13 us |
C
|
|
|
|
The excitation of the crytal generates an ultrasound wave via
A. Piezoelectric effect B. Converse piezoelectric effect C. Either |
B
|
|
|
|
As the echo strikes the transducer, an electric signal is induced in the transducer via
A. Piezoelectric effect B. Converse piezoelectric effect C. Either |
A
|
|
|
|
T or F
A-mode is a one dimensional portrayal of the amplitude of signal versus depth. |
True
|
|
|
|
T or F
In B-mode imaging, the amplitude of the signal is represented by the brightness of the dot. |
True
|
|
|
|
The following are problems present in B-mode that are not encountered in A-mode imaging
A. Determination of transducer position B. Storage of scan line information C. Determination of amplitude D. A and B E. A and C |
D
|
|
|
|
T or F
In B-mode imaging, a special scanning arm or registration arm is used to determine the transducer position. |
True
|
|
|
|
T or F
10-20 lines of sight is needed in B-mode scanning. |
True
|
|
|
|
Components of a CRT, except
A. Phosphor screen B. Plastic envelope C. Flood Gun D. Storage mesh |
B
|
Glass envelope
|
|
|
Gray scale displays for B-mode scanning uses this special system.
A. CRT B. scan converter C. registration arm |
B
|
|
|
|
Dielectric matrix is a component of
A. CRT B. Scan converter C. phosphor screen |
B
|
|
|
|
Components of the scan converter
A. Dielectric matrix B. Cathode and anode filament C. X and Y deflection plates D. Focusing cup E. all of the above |
E
|
|
|
|
Moves the electron beam across the dielectric matrix in B-mode scanning
A. Raster scan B. registration arm C. Both D Neither |
A
|
|
|
|
Small rectangular or square picture elements
A. Bit B. Pixel C. Voxel D. None |
B
|
|
|
|
The out of plane width of sound beam means that each pixel actually signifies three-dimensional volume of tissue.
A. Pixel B. Bit C. Voxel D. Vixel |
C
|
|
|
|
Major problem with B-mode and other static imaging
A. Poor spatial resolution B. Poor temporal resolution C. Both D. None |
B
|
|
|
|
Type of B-mode imaging, except
A. Static B-mode B. Gated-mode imaging C. C-mode s scanning D. ECG gated scanning E. Transmission mode imaging |
E
|
same with CT scan
|
|
|
A type of B-mode imaging designed to reduce motion artifacts obtained from static B-mode scanning.
A. ECG gated scanning B. C-mode scanning C. Transmission mode scanning |
A
|
|
|
|
An A-mode scan is a plot of the _____ in one dimension versus ___ in the other dimension.
A. Amplitude, Brigthness B. Brightness, Depth C. Amplitude, Depth D. None of the above |
C
|
|
|
|
The CRt time-base sweep rate corresponds to
A. 1 m per s B. 13 cm per 1 us C. 1 cm per 13 us D. None of the above |
C
|
|
|
|
T or F
The amplitude of the A-mode signal controls the emission of electrons from the cathode of the CRT. |
False
|
B mode, amplitude of B mode signal = brightness of dot
|
|
|
T or F
The CRT trace is updated at the rate equal to the PRF |
True
|
|
|
|
T or F
In B-mode scanning, increased amplitude of the signal increases the brightness of the dot. |
True
|
|
|
|
T or F
The B-mode signal amplitude controls the emission of electrons from the cathode of the scan converter when operated in write mode. |
True
|
|
|
|
The position generator is used to control the location of the dot on the display. The position generator supplies information to the
A. X- and Y- deflection plates B. Cathode C. Focusing cup D. Dielectric matrix |
A
|
|
|
|
Scan converters are analog or _____.
A. Prolog B. Mechanical C. Digital D. None of the above |
C
|
|
|
|
T or F
The B-mode registration arm is responsible for ensuring that the echo information from a particular interface is displayed at the same location, regardless of the transducer orientation. |
True
|
|
|
|
T or F
The scan converter is so named because this device switches back and forth from the line-by-line acquisition during collection to the raster read-out during display. |
True
|
|
|
|
What are the physical dimensions associated with a pizel in which a 30 x 30 matrix represents an area of 10 x 20 cm?
A. 33 mm x 67 mm B. 0.67 mm x 0.33 mm C. 3.3 mm x67 mm D. 0.33 cm x 0.67 cm |
D
|
|
|
|
T or F
Static B-mode imaging has good temporal resolution. |
False
|
static = no motion
|
|
|
C-mode scanning refers to ___ scanning.
A. Continuous B. Constant Depth C. Cross- reference D. Closed |
B
|
|
|
|
Gated scanning requires the following modifications to the standard B-mode scanner
A. Change the transmitter electronics B. Change in display C. Removal of registration arm D. None of the above |
D
|
B mode scanner needs registration arm
|
|
|
T or F
ECG- gated scanning results in longer scan time but decreased patients exposure to ultrasound. |
False
|
less time= less exposure
|
|
|
Gated scanning prevents the ____ of the echoes outside the depth of interest.
A. Occurrence B. Amplification and processing C. Detection D. All of the above |
B
|
|
|
|
T or F
Standard transmission mode imaging can be used for any area of the body without problem. |
False
|
|
|
|
Transmission mode imaging is the only technique that relies on echo-ranging principles.
|
False
|
|
|
|
Disadvantages of a sector transducer, except:
A. Scanning in between or behind ribs is impossible due to its small size B. The fixed focal length restricts the best lateral resolution to a limited range of depths C. Resolution of images deteriorates with distance fromthe transducer images D. Limted field of view due to small size |
A
|
|
|
|
T or F
Rectangular format cannot sample region behind the ribs. |
True
|
Sector can
|
|
|
A type of liquid path mechanical scanner that utilizes an acoustic mirror to alter the ultrasonic path for sweeping the beam.
A. Reflecting liquid path B. Non- reflecting liquid path C. Contact mechanical scanner D. None of the above |
A
|
|
|
|
Liquid path transducers are smaller than those in contact scanner and more easy to use in between and behind ribs scanning.
|
False
|
|
|
|
True with mechanical scanners; except:
A. less expensive B. easier to operate C. troublesome to operate D. high quality images are produces |
C
|
|
|
|
True with electronic real time scanners; except
A. High quality images B. Limited lifetime due to wear and tear C. Higher frame rates D. Many lines of sight |
B
|
wear and tear is a cha of mechanical scanner
|
|
|
Electronic real-time scanners are generally classified as linear array and______.
A. Contact array B. Liquid path array C. Phased array D. None of the above |
C
|
|
|
|
A type of electronic real time array composed of multiple crystals aranged one after the other in a straight row.
A. Segmented linear array B. Sequential linear array C. Both |
B
|
|
|
|
Sequential Linear array
A. composed of small crystals in a row B. short narrow near field, rapidly diverging far field C. Both D. None of the above |
B
|
|
|
|
Stepdown segmental linear array
A. Produces good temporal resolution B. Higher frame rate C. Larger crystal size D. Good spatial resolution (beam size and number of lines per sight) E. All of the above |
E
|
|
|
|
The in plane direction is the length direction while the out of plane direction is the _____ direction in focusing.
A. Height B. Width C. Diameter D. None |
B
|
|
|
|
T or F
Linear arrays can be mechanically focused in the length direction. |
False
|
Electronic focusing = length
Mechanical focusing = out of plane/ width |
|
|
Electronic focusing obeys what?
A. Snell's Law B. Huygens principle C. Rayleigh scatter D. Logarithmic summation of US waves |
B
algebraic summation constructive and destructive interference |
|
|
|
The ____ timing is accomplished by delay lines in electronic focusing.
A. Microseconds B. Milliseconds C. Seconds D. Nanoseconds |
D
|
|
|
|
T or F
In mechanical real-time systems, the focal depth is fixed. |
True
|
Linear array, sonographer can move the focal depth
|
|
|
Transmit focusing is a multizone focusing technique (combining multiple zones)to optimise focusing at many depths.
|
True
|
|
|
|
Quasi-focusing technique is based on beam aperture.
|
True
|
|
|
|
Types of electronic focusing; except
A. Fixed transmit focusing B. Dynamic receive mode focusing C. Quasi-focusing D. None of the above |
D
|
|
|
|
True of electronic real time phased array, except
A. Small transducer with few crystals B. All crystals are fired at the same time C. Produces a rectangular format D. None of the above |
C
|
Sector
|
|
|
Phased array
A. Electronic steering B. Dynamic fixed transmit focusing C. Receive mode focusing D. Crystals are either rectangular or annular format E. All of the above |
E
|
|
|
|
Rectangular phased array
A. Electronically focused on both direction B. Mechanical focusing is necessary C. Both D. None of the above |
A
|
|
|
|
Annular phased array
A. Have a central crystal surrounded by concentric rings of additional crystals B. Mechanical steering is necessary using mirror (liquid path system) C. Both D. Neither |
C
|
|
|
|
Formation of secondary lobes is one of the major problem with electronic arrays.
|
True
|
|
|
|
Side lobes
A. Present in all transducer B. Caused by width and length mode vibrations C. Low intensity (60-100dB) than the main intensity D. All of the above |
D
|
|
|
|
A technique that lowers the intensity of side lobes for electronic array
A. Quasi technique B. Apodization C. Beam steering D. None of the above |
B
|
|
|
|
T or F
Curved (convex) linear arrays have large sector types of format with secondary lobe problems. |
False
|
less in curved array
|
|
|
Secondary lobes are side lobes and _____.
A. Grating lobes B. Lower Lobes C. Higher Lobes |
A
|
|
|
|
T or F
Grating lobes are caused by periodic spacing of elements and creates artifacts by measuring the time of flight to an object located outside the main beam. |
True
|
|
|
|
Ways to modify grating lobes, except
A. Apodization B. Changing the spacing distance C. Subdicing |
A
|
Apodization= side lobes
|
|
|
Preventing cross-talking between crystals in an array
A. Electrical isolation B. Mechanical isolation C. Both D. Neither |
B
|
|
|
|
Endosonography or transonography is also called pan-position indicator transducer can be inserted to various body cavities.
|
True
|
|
|
|
Types of endosonography probes; except.
A. Top-mounted B. End-mounted C. Side-mounted D. Right-mounted |
D
|
|
|
|
New real time imaging systems
A. Quasi real time imaging B. Ultrafast scanning C. 3-dimensional US holography D. A nd B E. All of the above |
E
|
|
|
|
T or F
Real-time imaging provides excellent temporal resolution. |
True
|
Static (spatial resolution)
|
|
|
T or F
Real time imaging allows multiple lines of sight for each image and multiple images to be collected each second. |
True
|
|
|
|
T or F
The maximum frame rate in real time imaging is directly proportional to the depth of interest. |
False
|
FR = PRF/N
FRm = C/ 2DN |
|
|
T or F
The maximum frame rate is directly proportional to the velocity of US in the medium. |
True
|
FRm = c/2DN
|
|
|
The maximum frame rate is indirectly proportional to the number of lines of sight for each image.
|
True
|
FR = c/ 2D n
|
|
|
The maximum frame rate is reduced if the number of fixed focal zones is increased in the absence of coprocessing.
|
True
|
|
|
|
Spatial resolution of the real-time image is not dependent of the number of lines of sight.
|
False
|
|
|
|
Changing the depth from 10 to 15 cm increases the maximum frame rate.
|
False
|
|
|
|
A registration arm is required in real-time imaging.
|
False
|
|
|
|
What are the two major classes of real-time imaging systems.
A. Mechanical, electronic B. Electronic, Contact C. Mechanical, Sector D. Water path, offset |
A
|
|
|
|
Liquid-path system allow higher frame rate compared with non-liquid path systems.
|
False
|
electronic array= higher FR
|
|
|
Liquid path systems are classified as reflecting or non-reflecting.
|
True
|
|
|
|
Electronic linear array real-time systems mechanically focus the beam in the width direction.
|
True
|
Length- electronically focused
|
|
|
The mechanical motion of mechanical real-time units generally prohibit very high frame rates.
|
True
|
|
|
|
Electronic linear phased array systems are electronically steered across the region of interest.
|
True
|
width= mechanical
|
|
|
T or F
The collection time for each line of sight for a real-time transducer, whether mechanical or electronic depends on the transit time of the pulse down and back (time of flight). |
True
|
|
|
|
T or F
Multiple crystals are excited simultaneously in a segmental linear array to improve the image quality by producing an effective wider aperture |
True
|
non-segmental/ sequential= fired in sequence
|
|
|
Effective in-plane (length) focusing of US beam for electronic real-time systems is accomplished using ______ and _____.
A. Mechanical focusing B. Delay lines C. Changing beam aperture D. A and C E. B and C |
E
|
Mechanical focusing = width(out of plane) direction
|
|
|
Dynamic focusing normally refers to
A. Transmit focusing B. Receive focusing C. A and B D None of the above |
B
DR(dynamic receive) FT (fixed transmit) |
|
|
|
Coprocessing uses multiple US beams with different focal zones acquire multiple lines of sight simultaneously.
|
True
|
|
|
|
Microsecond time delays are necessary for electronic focusing and phased array steering.
|
False
|
Nanosecond
|
|
|
Phased rectangular array transducers steered and focused in ___ dimension(s).
A. One B. Two C. Three D None of the above |
B
|
length and width
|
|
|
T or F
Annular arrays are electronically steered. |
False
|
Annular arrays mechanically steered using mirror
|
|
|
T or F
Compound linear arrays can be steered to widen the field of view. |
True
|
|
|
|
T or F
Convex arrays produce a large number of grating lobes because of beam steering. |
False
|
Convex array= less grating lobes
|
|
|
Arrays can be mechanically and electronically isolated to prevent cross-talk.
|
True
|
|
|
|
T or F
Translumenal probes are mechanical in nature. |
False
|
|
|
|
T or F
Dynamic receive focusing decreases the frame rate. |
False
|
|
|
|
Consider a sequential array with 10 crystals. How much time is required to form one image if the depth of interest is 10 cm?
A. 13 us B. 130 us C. 1300 us D. 13 ms |
C
|
1 cm per 13 us
|
|
|
T or F
If the transducer moves towards the receiver the Doppler frequency increases |
True
|
away= f decreases
|
|
|
The difference between the transmitted frequency and the observed frequency
A. Doppler signal B. Doppler frequency C. Doppler shift D. None of the above |
C
|
|
|
|
An increase in velocity of the interface correspond to an increase in Doppler shift.
|
True
|
|
|
|
Ignoring the contribution of Doppler angle causes underestimation of the true velocity.
|
True
|
|
|
|
RBC exhibits
A. Rayleigh scatter B. Specular reflection C. Both D. Neither |
A
|
|
|
|
Depth has nothing to do with Doppler frequencies.
|
False
|
f =90/d
|
|
|
True of continuous wave Doppler units; except
A. two (D shaped) crystals in the transducer B. Operating frequency above 7 MHz C. Crystals are mechanically focused D. None of the above |
B
|
<7 MHz
|
|
|
Doppler probe usually operates in what frequency
A. 2-10 MHz B. 2-5 MHz C. 5-10 MHz |
A
|
|
|
|
T or F
The filter is used to remove "wall thump". |
True
|
|
|
|
T or F
Doppler imaging needs a scanning arm to denote position of the transducer. |
False
|
|
|
|
T or F
Waves of different frequencies algebraically add together giving a resulting frequency called Beat frequency. |
True
|
|
|
|
T or F
A mode is mainly used to measure distance. |
T
|
|
|
|
Spatial pulse length is determined by
a. oscillator b. pulser c. pulser oscillator d. all of the above |
d
|
|
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|
Annular arrays steers the beam
a. axially b. electronically c. mechanically d. none of the above |
c
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T or F
A half-value layer is the amount of material required to reduce the intensity of the beam by a factor of 2. |
T
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Which of the following is not a transducer factor
a. electromechanical coupling coefficient b. transmission coefficient c. reception coefficient d. Decibel e. Q, mechanical coefficient |
d
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During processing of the ultrasonic signal, integration is performed following
a. rectification b. display of A-mode spike c. enveloping (video signal) d. reception of the echo |
c
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T or F
The Doppler angle is not considered in the calculation of velocity in color Doppler imaging |
F
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The technique of frame averaging during real-time acquisition is designed to
a. reduce random noise b. decrease pixel size c. redistribute the gray scale d. enhance spatial resolution |
a
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The comet tail artifact is related to
a. reverberation b. resonance c. attenuation d. none of the above |
a
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The ring-down artifact is related to
a. reverberation b. resonance c. attenuation d. none of the above |
b
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Smaller transducers always produce smaller beam diameters. T or F
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False
depends on focusing, whether near field or far field |
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Linear phased array scanners need no form of mecahnical focusing since focusing is performed in electronically.
T or F |
F
slice thickness requires mechanical focusing |
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The ratio of particle pressure to particle velocity at a given point within the ultrasonic field is
a. interference b. impedance c. incidence d. noise |
b
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The product of the period and number of cycles in the pulse is the
a. pulse repetition frequency b. continuous wave c. pulse repetition period d. pulse duration |
d
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Which of the following is the least obstacle to the transmission of ultrasouns?
a. muscle b. fat c. bone d. blood |
d
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When electric voltage is applied on both faces of a piezoelectric crystal, the crystal will
a. increase in size b. decrease in size c. lose its polarization d. increase or decrease in szie depending on the voltage polarity |
d
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The duty factor of a pulsed echo system is usually less than
a. 10% b. 100% c. 1% d. 25% |
c
pulsed echo system spends most of the time listening to returning echo signal |
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What happens to the ultrasound beam beyond the critical angle?
a. 100% is transmitted b. 100% is reflected c. 75% is transmitted, 25% is reflected d. 75% is reflected, 25% is transmitted |
b
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