Physics Quiz 6

Front 1

You are imaging a fluid filled structure that has equidistant horizontal bands appearing in the near field. The bands have decreasing brightness with depth. What artifact are you imaging?
a. slice thickness
b. side lobes
c. reverberation
d. comet tail
e. ring down

Back 1

c

Front 2

The waveform you obtained from an arterial stenosis demonstrates aliasing. If you increase the PRF to eliminate the aliasing, what artifact could be introduced?
a. multipath reflections
b. spectrum mirror image
c. propagation speed error
d. range ambiguity
e. refraction

Back 2

d

Front 3

You have obtained an ultrasound image that demonstrates refraction of the sound beam. This artifact might be manifested as:
a. axial displacement of a reflector
b. enhancement distal to a refelctor
c. lateral displacement of the displayed position of a reflector
d. multiple images of a single reflector
e. increased brightness of a reflector

Back 3

c

Front 4

Which of the following conditions will result in aliasing of the doppler frequency shift using continuous wave doppler?
a. PRF 10 kHz, frequency shift 4 kHz
b. PRF 12 kHz, frequency shift 8 kHz
c. PRF 5 kHz, frequency shift 2.3 khz
d. PRF 8 kHz, frequency shift 5 khz
e. none of the above

Back 4

e

Front 5

You are using a transducer that produced that produced a beam with a very wide slice thickness. Which of the following problems are you most likely to encounter as a result?
a. increased near field reverberations in fluid structures
b.increased side lobes
c. decreased penetration
d. partial volume artifact
e. decreased frame rate

Back 5

d

Front 6

You may observe a mirror image artifact with witch imaging mode?
a. b mode
b. spectral doppler
c. color doppler
d. power doppler
e. all of the above

Back 6

e

Front 7

Which of the following artifacts may result in both axial and displacement of a reflector on the ultrasound beam?
a. refraction
b. side lobe
c. multipath reflections
d. partial volume
e. enhancement

Back 7

c

Front 8

Which imaging technique may increase visualization of the reflections from blood flow on the real time ultrasound image?
a. compound imaging
b. tissue harmonic imaging
c. 3D imaging
d. tomographic imaging
e. speckle reduction imaging

Back 8

b

Front 9

While scanning a curved structure, you notice shadowing at the lateral edges of the structure. What is required for this artifact to occur?
a. different media propagation speeds
b. perpendicular incidence
c. transmit frequency exceeding 5MHz
d. fluid-filled structure in the oath of the beam
e. phased array transducer

Back 9

a

Front 10

Which artifact is being described in the previous question?
a. grating lobes
b. comet tail
c. acoustic speckle
d. ring down
e. refraction

Back 10

e

Front 11

Which of the following artifacts is the result of reverberation?
a. comet tail
b. acoustic speckle
c. beamwidth
d. refraction
e. all of the above

Back 11

a

Front 12

Which of the following artifacts commonly results in echoes filling in the lumen of small vessels?
a. refraction
b. partial volume
c. mirror image
d. range ambiguity
e. multipath

Back 12

b

Front 13

Propagation speed error results in which sonographic appearance?
a. improper lateral position of an echo
b. improper axial position of an echo
c. shadowing behind an echo
d. enhancement behind an echo
e. none of the above

Back 13

b

Front 14

When you select harmonic imaging, which artifact is less likely to be observed?
a. refraction
b. shadowing
c. ring down
d. grating lobes
e. speed of soung

Back 14

d

Front 15

When you select compound imaging, which artifact is less likely to be observed?
a. refraction
b. shadowing
c. enhancement
d. acoustic speckle
e. all of the above

Back 15

e

Front 16

The salt and pepper appearance on an ultrasound image is a result of:
a. acoustic speckle
b. compound imaging
c. harmonic imaging
d. electromagnetic interference
e. refraction

Back 16

a

Front 17

An image exhibits banding. This is a result of:
a. dead transducer element
b. incorrect TGC
c. incorrect master gain
d. incorrect focal zone position
e. incorrect probe pressure

Back 17

b

Front 18

What imaging artifact is much worse on the left phantom image compared to the right phantom image?
a. reverberation
b. volume averaging
c. range ambiguity
d. multipath
e. refraction

Back 18

b

Front 19

What type of transducer will improve the artifact demonstrated in the previous question?
a. linear array
b. 1.5D or multi-row array
c. mechanical 3D
d. phased array
e. mechanical sector

Back 19

b

Front 20

This image was obtained with a linear array transducer that employs phasing to steer the beam. What artifact do the arrows point to?
a. grating lobes
b. reverberation
c. mirror image
d. slice thickness
e. multipath reflectors

Back 20

a

Front 21

What can be done to reduce the presence of the artifact seen in the previous question?
a. reduce or eliminate beam steering
b. change the angle of incidence
c. dynamic aperture
d. increase number of rows of elements in z axis
e. decrease number of focal zones

Back 21

a

Front 22

Complete destructive interference of echo reflections will affect the display in the following way:
a. bright white pixel
b. black pixel
c. dark gray pixel
d. light gray pixel
e. none of the above

Back 22

b

Front 23

You are observing a sonographic artifact based on the interference patterns of scattered echoes. What artifact are you imaging?
a. mirror
b. grating lobe
c. acoustic speckle
d. comet tail
e. refraction

Back 23

c

Front 24

Which of the following will improve the artifact you are imaging in the previous question?
a. use frame averaging
b. use compounding imaging
c. reduce the output power
d. increase the overall gain
e. a and b

Back 24

e

Front 25

If you wish to improve border definition, what imaging enhancement should you use?
a. use a lower line density
b. use a 2D array transducer
c. use spatial compounding imaging
d. apply a speckle reduction algorithm
e. use frame averaging

Back 25

c

Front 26

Which artifact is associated with resonance of a gar bubble?
a. grating lobes
b. comet tail
c. acoustic speckle
d. ring down
e. refraction

Back 26

d

Front 27

What technique would be most helpful in reducing grating lobes in your image?
a. beam steering
b. compound imaging
c. 3D imaging
d. speckle reduction imaging
e. tissue harmonic imaging

Back 27

e

Front 28

What technique would be most likely to produce grating lobes in your image?
a. beam steering
b. tomographic ultrasound
c. 3D imaging
d. speckle reduction imaging
e. tissue harmonic imaging

Back 28

a

Front 29

Which artifact is related to beam attenuation?
a. comet tail
b. aliasing
c. enhancement
d. reverberation
e. side lobe

Back 29

c

Front 30

What artifact might you see with an array transducer due to energy that propagates from the transducer in a direction different from the primary beam?
a. grating lobe
b. mirror image
c. reverberation
d. range ambiguity
e. acoustic enhancement

Back 30

a

Front 31

What is inadequate temporal resolution?

Back 31

If the FR is too slow, motion of fast moving structures will appear jerky and fine details of this motion will not be displayed

Front 32

FR=?

Back 32

PRF/L
1540 m/sec/2d

Front 33

What is acoustic shadowing?

Back 33

The low signal is caused by absorption and reflection of the ultrasound beam at the interface with a strong reflector

Front 34

What does acoustic shadowing appear like?

Back 34

Dark streaking behind highly attenuation objects such as bones or calcified plaque

Front 35

What is acoustic enhancement?

Back 35

As sound travels through a weakly reflecting structure, it attenuated very little. Thus, strong reflectors beneath it receive relatively strong sound waves and appear very bright on the screen

Front 36

What structures might produce acoustic enhancement?

Back 36

cyst or urinary bladder

Front 37

What is reverberation caused by?

Back 37

the reflection of ultrasound several times back and forth between two closely spaced interfaces

Front 38

What is another name for the "ping pong effect?"

Back 38

reverberation

Front 39

Reverberation can be _____ interface or _____ _____ tissue interfaces

Back 39

transducer
two different

Front 40

In reverberation, the multiple echoes created give rise to _____ ______ _______ ______ ______. These are displaced to greater depths in the image.

Back 40

Multiple copies of the anatomy.

Front 41

What is a comet tail artifact?

Back 41

another reverberation artifact that occurs due to reverberation within a small highly relfective object

Front 42

Whats a ring down artifact?

Back 42

reverberation occurs within a small bubble of gas or liquid. It can also be caused by reverberation of a bubble itself. Similar to comet tail

Front 43

What is refraction?

Back 43

US changes direction of propagation

Front 44

What is refraction shadowing?

Back 44

increase or decrease in intensity due to a curved refracting surface

Front 45

What is mirror image artifact?

Back 45

sound is redirected by a strong reflector to another reflector
echoes from the 2nd reflector return back following the same path
on the display both object and mirror artifact are displayed

Front 46

Sound follows what path during mirror image artifact?

Back 46

probe>1st reflector>2nd reflector>1st reflector>probe

Front 47

What is multipath artifact?

Back 47

sound is reflected by a strong reflector to another reflector
echoes from the 2nd reflector return directly to the probe (dont follow the same path)
on the display, reflector is positioned deeper than the true anatomical structure

Front 48

Sound follows what path during multipath artifact?

Back 48

probe>1st reflector>2nd reflector>probe

Front 49

Whats a side lobe?

Back 49

produced by a single crystal transducer and are due to radial vibration of the crystal as opposed to vibration in the thickness direction causing the main beam

Front 50

To reduce side lobe emission, crystals are designed with diameter at least _____ times larger than US wavelength

Back 50

10

Front 51

Whats a grating lobe?

Back 51

the multiple small crystal elements of electronic array transducers may have the affect of a grating lobe