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80 Cards in this Set

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  • Back
What determines the frequency of the transducer
The thickness of the transducers element and the propagation speed of the transducer material
You are performing an ultrasound exam with a wide bandwith transducer. What is the advantage you obtain with this transducer compared to a narrow bandwith transducer?
Improved Axial resolution
Which of the following can best improve lateral resolution: Increase damping, Decreased frequency, Increased bandwith, Use of a curved crystal, or Decreased aperature?
Use of a curved crystal
What is the location where the sound beam reaches its narrowest diameter known as?
Focal Zone
You are using a type of focusing that varies the number of cycles being fired in a segment, what is this called?
Aperature focusing
Which type of transducer produces a sector image shape?
Phased and Annular array
What is the term for a transducer that an array of rectangular elements are arranged in a straight line?
Linear Array
For linear array transducer, which method of focusing is used to focus the beam in the elevational direction?
Mechanical focusing
What transducer produces a beam that is symmetrical about the beam axis?
Annular array
A transducer with a small foot print has which of the following disadvantages: Its too large to use for intercostals scanning, The far field of view is only 1/4 the diameter of the transducer, The Q value is very high, or Focusing degrades at a depth of twice the transducer aperature
Focusing degrades at a depth of twice the transducer aperature
Which of the folllowing will not improve axial resolution: Increased Damping, Increased Transducer frequency, Increased bandwith, decreased pulse length, or Increased focusing
Increased focusing improves lateral resolution
You are reviewing an ultrasound image that has a sector display format with a pointed top. What kind of transducer produced this image?
Phased array
Where is the point of maximum intensity in a sound beam called?
Focal point
Constructive and destructive interference of sound waves from each individual sound source of a transducer is known as what?
Huygens principle
Increasing the transducer diameter has which of the following effects: Increased near zone length, Increases the frequency, Increases the beam diameter in the far field?
Increases the near zone length
A linear array transducer with 4 transmit focal sones selected requires how many pulses on each vector to create the image?
If you wish to adjust the focusing characteristics while scanning with a curved linear array, what type of focusing are you manipulating?
Multizone transmit
Which of the following transducers is electronically focused but mechanically steered: Segmental linear array, Switched linear array, Phased linear array, Single element mechanical sector, or Annular array?
Annular array
What type of transducer has the same measurement for elevational and lateral resolution?
Annular array
You are using a linear array transducer to image a thyroid mass and would like to use a transducer in which the thinnest slice is close to the depth of the mass. Where is the thinnest width of the sound beam in the out-of-plane dimension?
It is at the point of mechanical focusing
If you wish to produce a sonogram in a rectangular format, what transducer should you choose?
Linear array
What is another name for axial resolution?
Range (L.A.R.R.D Longitudinal axial range radial depth)
Dynamic apodization is a method employed to do what?
Reduce side lobes
If you measure the width on a standard one dimensional linear array transducer, which measure of resolution would be the worst: Axial, Lateral, Elevational, Contrast, or Temporal?
What should you do to obtain the best lateral resolution for a given transducer?
Use the maximum number of transmit focal zones
You have detected a small hyperechoic focus within the gallbladder. There is no distal acoustic shadow. What can you do to aid visualization of the shadow?
Increase the transducer frequency
You are scanning a phantom containing many small spherical cystic structures imbedded in a tissue mimmicking material, what type of resolution is best evaluated with this phantom?
Which statement is not true regarding lateral resolution: It is equal to beam width, It is improved by focusing, It is defined as the minimum separation required to resolve two structures perpendicular to the beam axis, It is also known as the azimuthal resolution, or It remains constant throughout scanning depth
It remains constant throughout scanning depth
Which type of transducer will decrease the slice of thickness of the beam?
A linear array with multiple rows of elements
What is the algebraic sumnation of waves called?
What is the matching layer between the piezoelectric element and the tissue designed to do?
Reduce the acoustic impedance mismatch between the element and tissue
What does dynamic receive focusing use?
Delay lines after the echoes are detected in the array elements
What transducer factor characterizes the frequency bandwith of the transmitted ultrasound wave?
The Q-Value
Varying the excitation voltage to each crystal in the group used to form the ultrasound pule is called what?
Describe a phased array transducer.
Electronically focused along the length os the array mechanically focused along the width, and electronically steered
Resolution of the two structures parallel to the path of the sound beam is termed what?
Axial resolution
Which transducer has the same line density in both the near and far fields?
Linear array
Which of the following technical features minimizes the degree to which beam width varies with depth: Apodization, Dynamic aperature, Copredessing, Rectification, Frame averaging
Dynamic Aperature
The sound beam can be focused by all of the following except which: Acoustic mirror, Acoustic lens, Curved crystal, Matching layer, or Electronic phasing?
Matching layer
What type of focusing decreases the frame rate?
Multiple transmit focusing
For a single thansducer to offer multiple frequency scanning selections it must have what?
Wide bandwith
The ability to distinguish between adjacent structures that produce echoes of similar amplitude is termed what?
Contrast resolution
Increasing scan line density will improve what?
Lateral resolution
The conversion of an incident pressure wave to an electrical signal is what?
The piezoelectric effect
Electronic focusing in the transmit mode is accomplished how?
Time delays to excite crystal elements
What is the purpose of subdicing?
To reduce grating lobes
What transducer component is designed to control piezoelectric element ringing?
Backing material
The transducer you are using is an array assembly. What is an advantage of this type of transducer?
Transducer arrays enable electronic focusing and steering
Which of the following is not associated with a low Q transducer: wide bandwith, multifrequency selection, long pulse length, diagnostic pulsed waved ultrasound, loss of most energy in first few vibrations?
Long pulse length
An internal method of focusing is what?
Curved piezoelectric element
If the number of cycles in the transmitted pulsed wave is increased what will be degraded?
Axial resolution
You have been requested to image a superficial mass and to adjust your equipment to maximize spatial resolution. Spatial resolution consists of what?
Lateral and Axial resolution
What is the purpose of the radiofrequency shield that is placed around the crystal and backing material of the ultrasound probe?
It reduces electromagnetic interference
An electronic method of reducing transducer ringing and improving axial resolution is termed what?
Dynamic damping
What type of resolution is affected most by pulse duration?
Axial resolution
With a standard one dimensional linear array transducer what type of resolution is affected most by aperature size?
Elevational resolution
The spectrum of frequencies emitted by a pulsed wave transducer is known as what?
What is the optimal thickness for the matching layer?
one fourth of a wavelength
What is a method used to improve frame rates with multizone electronic focusing termed?
Aperature focusing
If you want to use an array transducer that allows you to control transmit focal depth, what type would you select?
Linear array, Convex array, Phased array, Annualar array
If you want to perform an abdominal sonogram with the largest possible field of view in both the near field and depth, what type of transducer would be most preferable?
Convex array
You are using a linear array transducer to evaluate the thyroid gland, for standard B mode imaging, this modern day transducer most likely produces pulses of how many cycles?
One to three
What is the purpose of applying multiple matching layers to the transducer face?
Each matching layer thickness is optimized for a different frequency of the transmitted bandwith which improves sound transmission at the element-tissue interface
For nonfocused transducer, the region between the transducer element and the point at which the sound beam is narrowest is called what?
Near zone distance
What is the minimum beam diameter for an unfocused disk transducer?
1/2x disk diameter
You must obtain intercostals views to image a liver mass on a small elderly woman, but the large probe you are using does not provide sufficient contact. What probe would be most helpful in this situation?
Phased array
You have been asked to perform an endovaginal examination of a patient postmenopausal bleeding to evaluate the endometrial thickness. What is the main advantage of scanning endovaginally compared to scanning with a conventional curved linear array through the pelvis?
Since the endovaginal probe is closer to the area of interest, a higher frequency transducer can be used, resulting in superior spatial resolution
What defines the best axial resolution that can be obtained with a given transducer?
Spatial pulse lenght / 2
The ultrasound system in your lab has multiple transducers that exhibit different axial resolution for the following axial resolution measurement, which offers the finest detail: .77, .44, .31, .20, or .15mm
What term describes the ability of sound to separate closely spaced objects?
What happens when pressure is applied to a piezoelectric crystal?
It emits an electrical signal
How is beam focused with a single element transducer?
With a curved element
What arrary transducer fires all of the elements at once with very small time differences to create the beam?
Linear segmental array, Convex array, Annular array, Linear sequential array, and phased array
Increasing the following parameter will improve axial resolution: Pulse duration, Pulse length, Frequency, Period, or Focusing?
Which represents the best measure of resolution for modern day ultrasound scanner: Contrast, Axial, Elevation, Temporal, or Lateral?
Which of the following transducers produces side lobes: Mechanical sector, Linear sequential array, Phased array, Convex array or all
All of them
You are scanning the abdomen of an average sized 8yr old with a 3.5MHz Convex array probe. What comprimise are you making by selecting this probe?
Decreased spatial resolution
Which type of transducer is best suited for small parts imaging?
Linear array
Which of the following transducer types is best suited for cardiac imaging: Mechanical, Linear, Phased, Convex, or Annular
Phased array
Which of the following can not be evaluated with a tissue equvalent phantom: Axial resolution, Lateral resolution, Contrast resolution, Slice thickness, Temporal resolution
Temporal resolution