Part 2 Flashcards
(162 cards)
1
Q
Which of the following is caused by slice thickness artifact?
a) curved reflectors in the path of the sound beam
b) beam dimension greater in size than the reflector
c) bending of the sound beam during transmission
d) near field length too long
e) decreased attenuation of the sound beam at the reflector
A
b) beam dimension greater in size than the reflector
2
Q
The general mechanism which creates harmonics is __.
a) turbulent behavior
b) Nyquist limits
c) Poiseulle’s flow
d) Bernoulli flow
e) non linear behavior
A
e) non linear behavior
3
Q
What is the relationship between pulse duration and temporal resolution?
A
they are unrelated
4
Q
In a B-mode display, which of the following CRT inputs are used with the amplitude of the reflection?
a) x axis
b) z axis
c) y axis
d) m axis
e) time base axis
A
b) z axis
5
Q
Which of the following statements about Doppler is most correct?
a) non directional Doppler uses non-coherent processing, while bi-directional Doppler uses phase-quadrature processing
b) non-directional Doppler uses FFT processing, while bi-directinoal Doppler uses Nyquist processing
c) non-directional Doppler uses autocorrelation processing, while bi-directional Doppler uses phase-quadrature processing
d) non-directional Doppler uses phase quadrature processing, while bi-directional Doppler use coherent processing
e) non-directional Doppler uses phase-singular processing, while bi-directional Doppler uses phase-quadrature processing
A
a) non-directional Doppler uses non-coherent processing, while bi-directional Doppler uses phase-quadrature processing
6
Q
Which of the following factors determine the spatial resolution of a monitor?
a) dynamic range
b) the number of lines per frame
c) the number of pixels per bit
d) the number of bits per inch
e) the number of pixels per inch
A
b) the number of lines per frame
7
Q
What will minimize attenuation?
A
short path lengths and lower frequencies
8
Q
If RBCs are traveling toward a transducer, the frequency emitted by the transducer is __ the frequency reflected from the blood cells.
a) greater than
b) equal to
c) less than
A
a) greater than
9
Q
What information does the Doppler shift furnish concerning the blood cells that produce it?
a) frequency
b) speed
c) velocity
d) density
A
c) velocity
10
Q
Two ultrasound transducers are used to perfrom Doppler exams on the same patient. The exams are identical except that the transducer frequencies are 5 and 2.5 MHz. Which exam will measure the highest velocities?
a) the 2.5 MHz
b) the 5 MHz
c) neither
d) cannot be determined
A
c) neither
11
Q
Two ultrasound transducers are used to perfrom Doppler exams on the same patient. The exams are identical except that the transducer frequencies are 5 and 2.5 MHz. Which exam will measure the highest Doppler shift?
a) the 2.5 MHz exam
b) the 5 MHz exam
c) neither
d) cannot be determined
A
b) the 5 MHz exam
12
Q
How many lines of sight interrogate the sample volume in pulsed wave spectral analysis?
a) 1
b) 100
c) 10
d) 1000
A
a) 1
13
Q
What is a characteristic of the spectral waveform if turbulence is present?
a) loss of flow coherence
b) high speed, uniform flow
c) laminar flow
d) no signal for the velocities less than the peak velocity
A
a) loss of flow coherence
14
Q
What is the change in the spectral waveform if the volume of flow through the sample volume is increased by 30% during the heart cycle?
a) peak velocity is higher
b) spectral shape is inverted
c) peak velocity is lower
d) no change in spectral shape
A
a) peak velocity is higher
15
Q
What is the cause of transit time broadening?
a) finite size of smaple volume
b) large Doppler angle
c) slow moving reflectors
d) high center frequency
A
a) finite size of sample volume
16
Q
What is the difficulty if the Doppler angle is increased above 60 degrees?
a) aliasing is more likely
b) didirectional flow cannot be measured
c) angle error is more pronounced
d) equation for Doppler shift frequency no longer applies
A
c) angle error is more pronounced
17
Q
What is the maximum velocity waveform?
a) time trace of the max velocity in each fast fourier transform segment
b) time trace of the max velocity in each heart cycle
c) time trace of the max velocity detected in each echo
d) time trace of the max velocity within the duplex field of view
A
a) time trace of the max velocity in each fast fourier transform segment
18
Q
What is the power spectrum?
a) frequency components in transmitted pulse
b) frequency components in the received echo
c) spectral analysis shown in the time domain
d) spectral analysis shown in the frequency domain
A
d) spectral analysis shown in the frequency domain
19
Q
What is indicated by the numerical limit of the velocity scale in the spectral waveform?
a) highest true velocity within the sample volume
b) highest true velocity within the vessel
c) max reflector velocity that can contribute to Doppler signal
d) max velocity that can be measured without aliasing
A
d) max velocity that can be measured without aliasing
20
Q
What affects Doppler signal amplitude?
a) number of RBC
b) direction of fow
c) flow velocity
d) Doppler angle
A
a) number of RBC
21
Q
What is the complex Doppler signal?
a) all Doppler shift frequencies in the sample volume
b) presence of aliasing artifact
c) Doppler shift frequencies partioned by depth
d) Doppler shift frequencies generated by turbulence
A
a) all Doppler shift frequencies in the sample volume
22
Q
What information is displayed in the Doppler spectral waveform?
a) velocity, signal strength, and time
b) flow volume and time
c) velocity, signal strength, and depth
d) flow volume and depth
A
a) velocity, signal strength, and time
23
Q
What method enables analysis of a complex Doppler signal into its individual frequency components?
a) rectification
b) fast fourier transform
c) autocorrelation
d) sideband
A
b) fast fourier transform
24
Q
How does increasing the velocity scale impact aliasing for spectral Doppler imaging?
a) it makes it worse
b) optimizes the PRF
c) improved detection of slow slow
d) shifts the baseline up
A
b) optimizes the PRF
25
Elimination of clutter due to tissue and wall motion is accomplished with __.
a) wall filter
b) reject
c) smoothing
d) color gain
a) wall filter
26
All of the following are benefits of asynchronous color doppler except:
a) frequency is optimized for gray-scale and doppler
b) transmit power is optimized for gray-scale and doppler
c) high frame rates
d) gray-scale resolution is better then synchronous mode
c) high frame rates
27
For PW Doppler, what is the dwell time?
a) another name for PRP
b) 1/PRF x SPL
c) time required to acquire 1 scan line for analysis of Doppler shift
d) the time you have spent thinking about this question
c) time required to acquire 1 scan line for analysis of Doppler shift
28
Mean Doppler shifts are displayed in which of the following?
a) PW
b) Spectral analysis
c) Color Doppler (CDI)
d) CW
c) Color Doppler (CDI)
29
A broader range of flow speeds and directions may be associated with __.
a) spectral artifacts
b) turbulent flow
c) laminar flow
d) none of the above
b) turbulent flow
30
What signal processing is used for the detection of Doppler shift echoes in CDI?
a) low pass filtering
b) beam former
c) autocorrelation
d) spectral analysis
c) autocorrelation
31
Doppler spectral analysis using __ is the most accurate.
a) zero crossing detectors
b) time interval histograms
c) fast fourier transforms
d) chirp-z transforms
c) fast fourier transforms
32
In PW Doppler, the number of pulses per scan line is called __.
a) scan rate
b) ensemble length
c) PRF
d) frame rate
b) ensemble length
33
What is the Doppler effect?
a) refraction along beam path causing a frequency shift
b) frequency shift due to relative motion between source and reciever
c) scattering from outside the main beam causing a frequency shift
d) frequency shift caused by specular reflection
b) frequency shift due to relative motion between source and reciever
34
What is observed if a reflector approaches the transducer at constant velocity?
a) echo frequency is higher than transmit frequency
b) echo frequency is lower than transmit frequency
c) echo frequency is the same transmit frequency
d) echo frequency changes as reflector gets closer to the transducer
a) echo frequency is higher than transmit frequency
35
What is observed if a reflector moves away from the transducer at constant velocity?
a) echo frequency is higher than transmit frequency
b) echo frequency is lower than transmit frequency
c) echo frequency is the same transmit frequency
d) echo frequency changes as reflector gets closer to the transducer
b) echo frequency is lower than transmit frequency
36
What is observed for a reflector moving at a constant velocity with a Doppler angle of 90 degrees?
a) echo frequency is higher than transmit frequency
b) echo frequency is lower than transmit frequency
c) echo frequency is the same transmit frequency
d) echo frequency changes as reflector gets closer to the transducer
c) echo frequency is the same transmit frequency
37
What is the sign indicator of the Doppler shift frequency if a reflector approaches the transducer at constant velocity?
a) positive
b) negative
c) zero
d) variable
a) positive
38
What is the sign indicator of the Doppler shift frequency if a reflector moves away from the transducer at constant velocity?
a) positive
b) negative
c) zero
d) variable
b) negative
39
What is the sign indicator of the Doppler shift frequency for a reflector moving at constant velocity with a Doppler angle of 90 degrees?
a) positive
b) negative
c) neither positive or negative
d) variable
c) neither positibe or negative
40
What is observed for a reflector moving at constant velocity with a Doppler angle of 30 degrees?
a) echo frequency is higher than transmit frequency
b) echo frequency is lower than transmit frequency
c) echo frequency is the same transmit frequency
d) echo frequency changes as reflector gets closer to the transducer
a) echo frequency is higher than transmit frequency
41
Which parameter is included in the equation for Doppler shift frequency?
a) propagation speed in tissue
b) viscocity of blood
c) time to echo
d) echo strength
a) propagation speed in tissue
42
Which parameter is included in the equation for Doppler shift frequency?
a) time to echo
b) viscocity of blood
c) transmitted frequency
d) echo strength
c) transmitted frequency
43
Which parameter is included in the equation for Doppler shift frequency?
a) time to echo
b) reflector speed
c) viscocity of blood
d) echo strength
b) reflector speed
44
Which parameter is included in the equation for Doppler shift frequency?
a) time to echo
b) angle to flow
c) viscocity of blood
d) echo strength
b) angle to flow
45
Why is aliasing a potential problem in pulsed wave spectral doppler?
a) small sample volume
b) curved vessels restrict sampling direction
c) intermittent smapling flow
d) flow through vessel is not constant during heart cycle
c) intermittent sampling flow
46
What is the result when the echo induced signal from a moving refector is algebraically added with the reference signal in continuous wave Doppler?
a) center frequency
b) Doppler shift frequency
c) second harmonic frequency
d) one-half the Doppler shift frequency
b) Doppler shift frequency
47
What is a feature of continuous wace Doppler?
a) depth information of moving reflectors
b) transmission with broad bandwidth
c) no upper velocity limit for moving reflectors
d) poor sensitivity to slow flow
c) no upper velocity limit for moving reflectors
48
What is a feature of continuous wace Doppler?
a) no depth information of moving reflectors
b) transmission with broad bandwidth
c) maximum velocity limit
d) poor sensitivity to slow flow
a) no depth information of moving reflectors
49
If the Doppler shift frequency is 1500 Hz at a center frequency of 2 MHz, what is the Doppler shift frequency for the same moving reflector if the center frequency is increased to 4 MHz?
a) 750 Hz
b) 1500 Hz
c) 2000 Hz
d) 3000 Hz
d) 3000 Hz
| when velocity doubles, doppler shift doubles
50
If the Doppler angle is changed from 45 degrees to 60 degrees, what is the effect on the observed Doppler shift frequency for a moving interface?
a) increases by a factor of 1.4
b) decreases by a factor of 1.4
c) remains the same
d) doppler shift frequency is zero
b) dereases by a factor of 1.4
51
If the Doppler angle is changed from 45 degrees to 60 degrees, what is the effect on the calculated velocity for a moving interface?
a) increases by a factor of 1.4
b) decreases by a factor of 1.4
c) remains the same
d) no doppler shift is observed
c) remains the same
52
What is a feature of continuous wave Doppler?
a) depth informationof moving reflectors
b) transmission with wide bandwidth
c) maximum velocity limit
d) high sensitivity to slow flow
d) high sensitivity to slow flow
53
What is the purpose of the wall filter?
a) removes the transmitted frequency from the echo signal
b) removes the beat frequency from the echo signal
c) removes harmonic frequencies in the Doppler signal
d) removes low frequency components in the Doppler signal
d) removes low frequency components in the Doppler signal
54
How is the axial dimension of the smapling volume in pulsed wave Doppler defined?
a) sample and hold
b) apodization
c) timing gates
d) transmitted frequency
c) timing gates
55
What detection method is used in pulsed wave spectral Doppler?
a) sample and hold
b) autocorrelation
c) pulsed wave inversion
d) multiple receive beam formers
a) sample and hold
56
Which signal processing technique enables the direction of motion in pulsed wave spectral Doppler?
a) sample and hold
b) autocorrelation
c) pulsed wave inversion
d) quadrature phase
d) quadrature phase
57
What is the artifactual display of a high frequency Doppler shift at a frequency lower than the true value?
a) mirror
b) aliasing
c) range ambiguity
d) high pass filtering
b) aliasing
58
What is the frequency dependence of the maximum velocity limit in pulsed wave Doppler?
a) Vmax becomes lower at high frequency
b) Vmax becomes greater at high frequency
c) Vmax is not changed until transmit frequency exceeds 5MHz
d) Vmax does not depend on transmit frequency
a) Vmax becomes lower at high frequency
59
What is a feature of duplex scanning using B-mode and spectral Doppler?
a) extends the maximum velocity limit
b) facilitates placement of the sampling volume
c) allows very high frame rates
d) increases the Doppler signal to noise ratio
b) facilitates placement of the sampling volume
60
What is the purpose of the fast fourier transform?
a) isolate the beat frequency
b) identify the Doppler shift frequencies
c) assign depth to the reflector
d) correct for aliasing
b) identify the Doppler shift frequencies
61
For constant, uniform velocity without aliasing, what is depicted in the Doppler spectral waveform?
a) oscillating peaks
b) straight vertical line
c) straight horizontal line
d) signal void
c) straight horizontal line
62
For constant flow velocity with aliasing in the pulsed wave spectral waveform, which adjustment could potentially remove aliasing?
a) decrease doppler angle
b) decrease transmit frequency
c) decrease velocity scale
d) decrease PRF
b) decrease transmit frequency
63
What is the change in the spectral waveform if the only component of flow altered is the number of RBC in the sampe volume is increased by 30%?
a) max velocity is increased
b) broadening of Doppler shift frequencies
c) no change in signal strength
d) no change in spectral shape
d) no change in spectral shape
| the number of RBC affects the strength of the doppler signal - changes in flow velocity affect shape
64
What is defined by the operator using the angle correct control?
a) direction of beam steering
b) direction of flow
c) depth of the sample volume
d) size of the sample volume
b) direction of flow
65
Why is the baseline positioned off center?
a) change the doppler angle
b) change the depth of the sample volume
c) expand the velocity range in one direction
d) expand the velocity range in both the forward and reverse directions
c) expand the velocity range in one direction
66
What is the function of spectral invert?
a) change the doppler angle
b) change the direction of beam steering
c) expand the velocity range
d) alter the direction assignment of the vertical axis
d) alter the direction assignment of the vertical axis
67
What is the purpose of Doppler reject?
a) removes the transmitted frequency from the echo signal
b) removes low amplitude signals from the spectral display
c) removes harmonic frequencies in the doppler signal
d) removes low velocity reflectors from the spectral display
b) removes low amplitude signals from the spectral display
68
What is the disadvantage of high PRF mode?
a) axial length of the sampling volume is degraded
b) depth assignment of moving reflectors is ambiguous
c) likelihood of aliasing is enhanced
d) shows flow in one direction only
b) depth assignment of moving reflectors is ambiguous
69
What is the advantage of high PRF mode?
a) improves designation of axial length of the sampling volume
b) improves depth assignment of moving reflectors
c) expands the maximum velocity without aliasing
d) reduces the error for large doppler angles
c) expands the maximum velocity without aliasing
70
If the timing delay for gate activation is changed from 52 microseconds to 48 microseconds, what is the effect of the doppler sampling volume?
a) axial length becomes longer
b) axial length becomes shorter
c) sampling volume is at decreased depth
d) sampling volume is at increased depth
c) sampling volume is at decreased depth
71
If the time for gate activation is changed from 2 microseconds to 1 microsecond, what is the effect of the doppler sampling volume?
a) axial length becomes longer
b) axial length becomes shorter
c) sampling volume is at decreased depth
d) sampling volume is at increased depth
b) axial length becomes shorter
72
What is an asynchronous scanner in Doppler imaging?
a) color and spectral Doppler collected at the same time
b) color and spectral Doppler collected separately
c) color and gray scale collected at the same time
d) color and gray scale collected separately
d) color and gray scale collected separately
73
Which term describes the group of pulses that interrogate one color line of sight?
a) spatial pulse length
b) ensemble length
c) PRF
d) coded excitation
b) ensemble length
74
What artifact in color Doppler imaging exhibits contiguous, contrasting colors within a vessel, indicative of maximum flow in the opposite directions?
a) color bleed
b) color aliasing
c) color noise
d) multiple angles to flow
b) color aliasing
75
How can the color aliasing artifact be eliminated?
a) decreasing the transmit power
b) increasing the width of the color field
c) changing the baseline
d) increasing the transmit frequency
c) changing the baseline
76
What detection method in color flow imaging enables analysis of the mean frequency in the Doppler signal?
a) heterodyne
b) autocorrelation
c) fast fourier transform
d) single sideband
b) autocorrelation
77
Why is autocorrelation instead of range gated, fast fourier transform used in Doppler imaging?
a) improved spatial detail
b) more accurate velocity measurement
c) power constraints
d) time constraints
d) time constraints
78
What is the purpose of the color gate in color Doppler imaging?
a) sets color signal threshold for display
b) adjusts axial length of color sampling volume
c) sets orientation of the color box
d) adjusts range of the velocity scale
b) adjusts axial length of color sampling volume
79
What is the purpose of the color reject in color Doppler imaging?
a) sets Doppler signal threshold for display
b) sets axial length of color sampling volume
c) sets threshold of Doppler shift frequency for display
d) sets regions of field of view where color is not displayed
a) sets Doppler signal threshold for display
80
What is the purpose of wall filter in color Doppler imaging?
a) removes the transmitted frequency from the echo signal
b) removes low amplitude signals from the color displau
c) removes harmonic frequencies in the Doppler signal
d) removes low frequency Doppler signals from the color display
d) removes low frequency Doppler signals from the color display
81
What is the output of the autocorrelation detector in color flow imaging?
a) spectral distribution of flow velocites
b) mean Doppler shift frequency
c) maximum Doppler shift frequency
d) signal strength for stationary detectors
b) mean Doppler shift frequency
82
What is the purpose of the color map in color flow imaging?
a) assigns velocity scale to various colors
b) sets regions of field of view where color is displayed
c) assigns Doppler signal level to various colors
d) assigns signal strength for stationary detectors to brightness levels
a) assigns velocity scale to various colors
83
What is the purpose of the color map in power Doppler imaging?
a) assigns velocity scale to various colors
b) sets regions of field of view where color is displayed
c) assigns Doppler signal level to various colors
d) assigns signal strength for stationary detectors to brightness levels
c) assigns Doppler signal level to various colors
84
Which Doppler technique is not susceptible to aliasing?
a) spectral doppler
b) asynchronous color flow imaging
c) power Doppler
d) synchronous color flow imaging
c) power Doppler
85
Which Doppler technique does not contain directional flow information?
a) spectral doppler
b) asynchronous color flow imaging
c) power Doppler
d) synchronous color flow imaging
c) power Doppler
86
Which Doppler technique is not constrained by Doppler angle?
a) spectral doppler
b) asynchronous color flow imaging
c) power Doppler
d) synchronous color flow imaging
c) power Doppler
87
Which does NOT affect the frame rate in color flow imaging?
a) width of the color field of view
b) color scan line density
c) packet size
d) color gate
d) color gate
88
What is the purpose of the color persistence in color Doppler imaging?
a) frame averaging of flow information
b) maximum velocity of the color scale
c) threshold of Doppler shift frequencies for color display
d) threshold of Doppler signal level for color display
a) frame averaging of flow information
89
What is the purpose of color gain in color Doppler imaging?
a) frame averaging of flow information
b) maximum velocity of the color scale
c) increase probability of color encoding of low volume flow
d) amplification of the Doppler signal
d) amplification of the Doppler signal
90
What artifact is color Doppler imaging inaccurately shows color extending to pixels adjacent to the vessel?
a) color bleed
b) color aliasing
c) color noise
d) multiple angles to flow
a) color bleed
91
What artifact is color Doppler imaging inaccurately shows color in hypoechoic regions such as fluid collections?
a) color bleed
b) color aliasing
c) color noise
d) multiple angles to flow
c) color noise
92
What artifact in color Doppler imaging is associated improper registration of color throughout the field of view caused by movement of the transducer
a) color bleed
b) color aliasing
c) color noise
d) color flash
d) color flash
93
What affects the frame rate in color flow imaging?
a) width of the color field
b) transmit power
c) color map
d) color gate
a) width of the color field
94
What affects the frame rate in color flow imaging?
a) color priority
b) color scan line density
c) color reject
d) color gain
b) color scan line density
95
What color represents forward flow in the BART color map?
a) blue
b) red
c) orange
d) yellow
b) red
96
What is the advantage of color flow imaging compared with pulsed wave spectral Doppler?
a) yields the distribution of flow velocities in each pixel
b) show the maximum flow velocity at each pixel
c) produces a global flow pattern
d) unlikely to contain aliasing artifacts
c) produces a global flow pattern
97
What is the disadvantage of color flow imaging compared with pulsed wave spectral Doppler?
a) color encodes a single metric, mean velocity
b) cannot indicate turbulence
c) slow updates of flow pattern, less than 5 frames per second
d) more likely to contain aliasing artifacts
a) color encodes a single metric, mean velocity
98
Which type of transducer utilizes time delay beam steering as the primary method to direct the beam throughout the field of view?
a) phased array
b) linear array
c) annular array
d) mechanical array
a) phased array
99
Which method to direct the beam throughout the field of view is used by the annular phased array?
a) time delay beam steering
b) sequence of selected element activation
c) voltage variation across the activated elements
d) mechanical movement
d) mechanical movement
100
Which type of transducer activates the elements in sequence to direct the beam throughout the field of view?
a) phased array
b) linear array
c) annular array
d) mechanical array
b) linear array
101
Which type of transducer provides electronic focusing in both the slice thickness direction and in-plane direction?
a) curvilinear array
b) linear array
c) phased array
d) annular array
d) annular array
102
Which type of transducer is unable to narrow the in-plane beam width by electronic focusing?
a) phased array
b) linear array
c) curvilinear array
d) mechanical sector
d) mechanical sector
103
For the linear array, what method is used to narrow the beam width in the elevational direction?
a) time delays
b) aperature
c) acoustic lens
d) apodization
c) acoustic lens
104
How does scan line density vary as function of depth for B-mode imaging using the phased array?
a) highest near the transducer
b) lowest near the transducer
c) highest in the transmit focal zone
d) constant for all scan depths
a) highest near the transducer
105
Which multiple element array transducer has constant scan line density throughout the scan range?
a) curvilinear array
b) linear array
c) phased array
d) mechanical array
b) linear array
106
What limits the width of the field of view for a linear array?
a) physical length of the array
b) numer of crystals in the array
c) scan range
d) timing sequence to crystal elements
a) physical length of the array
107
What is the basis for transmit electronic focusing to a specific depth using the linear array?
a) high PRF
b) number of crystals in the array
c) timeing sequence to the elements
d) presence of acoustic lens
c) timeing sequence to the elements
108
If the frame rate is 20 frames per second and the PRF is 4 kHz, how many lines compose a single B-mode frame? Assume two transmit focal zone.
a) 20
b) 100
c) 200
d) 2000
b) 100
109
Which change in transmission beam formation reduces the beam width near the face of a linear array transducer?
a) reduce the number of elements excited per pulse
b) increase the number of elements excited per pulse
c) reduce the number of scan lines per frame
d) increase the number of scan lines per frame
a) reduce the number of elements excited per pulse
110
As the transmit focal zone depth is extended, how is beam apperature changed?
a) decreased
b) increased
c) no effective change
d) depends on the center frequency
b) increased
111
What is the advantage of dynamic recieve focusing?
a) applied in the elevation direction
b) applied to all depths along the scan line
c) improves axial resolution
d) improves temporal resolution
b) applied to all depths along the scan line
112
What is the advantage of dynamic recieve focusing?
a) applied in the elevation direction
b) increases the scan line density
c) improves lateral resolution
d) increases the frame rate
c) improves lateral resolution
113
Which transducer is most likely to produce grating lobe artifacts?
a) annular array
b) phased array
c) mechanical sector
d) continuous wave Doppler
b) phased array
114
Which transducer provides electronic focusing in the elevation direction?
a) 1.5D array
b) phased array
c) linear array
d) curvilinear array
a) 1.5D array
115
What is a feature of the 2D matrix transducer?
a) electronic beam steering throughout the sample volume
b) frame rates greater than 100 frames per second
c) improved sensitivity
d) extended scan range
a) electronic beam steering throughout the sample volume
116
What is a CMUT?
a) beam former
b) 2D array of transducer elements
c) flat panel monitor
d) composite PZT
b) 2D array of transducer elements
117
What is the advantage of multiple transmit focal zones?
a) improved axial resolution
b) improved elevational resolution
c) improved lateral resolution
d) improved temporal resolution
c) improved lateral resolution
118
What is the disadvantage of multiple transmit focal zones?
a) loss in axial resolution
b) loss in elevational resolution
c) loss in lateral resolution
d) loss in temporal resolution
d) loss in temporal resolution
119
What term describes the communication pathway between a crystal element and the revieve beam former?
a) analog to digital converter
b) electrode
c) channel
d) apodization
c) channel
120
What is necessary to provide electronic focusing in the elevation direction?
a) multiple transmit pulses per scan line
b) multiple beam formers
c) multiple acoustic lenses
d) multiple rows of crystals
d) multiple rows of crystals
121
What is image format for a linear array?
a) sector
b) rectangular
c) trapezodial
d) all of the above
b) rectangular
122
What are the points of origin for the transmitted beams during autoscanning in a linear array?
a) across the transducer face
b) at the center of the array
c) mechanical movement of crystal elements
d) timing sequence of all crystal elements
a) across the transducer face
123
How many transmit focal zones are possible for one transmit pulsed beam?
a) one
b) equal to the number of excited crystals
c) equal to the number of channels
d) depends on the timing sequence of the elements
a) one
124
How does the vector array expand the width of the field of view compared with a linear array of the same size?
a) higher crystal density
b) beam steering
c) larger aperature
d) apodization
b) beam steering
125
What is (are) the point(s) of origin for the transmitted beams during autoscanning in a phased array?
a) each element across the transducer face in the sequence
b) at the center of the array
c) mechanical movement of the crystal elements
d) variable, depending on the scan range
b) at the center of the array
126
Which transmit focusing method varies the voltage applied to each element that contributes to the pulsed beam?
a) aperature
b) apodization
c) hanafy lens
d) subdicing
b) apodization
127
What does not contribute to the spatial dimensions fo a voxel in B-mode?
a) SPL
b) beam width
c) slice thickness
d) near field depth
d) near field depth
128
Which real time instrument measures the displacement of tissue when a force is applied?
a) spatial compounding
b) coded excitation
c) elastography
d) tissue harmonic imaging
c) elastography
129
If the transmitted frequency is 2 MHz, what is the frequency of the second harmonic?
a) 1 MHz
b) 2 MHz
c) 3 MHz
d) 4 MHz
d) 4 MHz
130
Which device applies dynamic receive focusing?
a) scan converter
b) beam former
c) amplifier
d) monitor
b) beam former
131
Which operator control adjusts the transmitted peak intensity?
a) scan range
b) power
c) PRF
d) dynamic range
b) power
132
What is the advantage of high transmit power?
a) increased penetration
b) improved axial resolution
c) decreased mechanical index
d) increased maximum frame rate
a) increased penetration
133
Which operator control can improve the visualization of weak reflectors?
a) scan range
b) power
c) read zoom
d) cine
b) power
134
Why is compression applied during signal processing before input to the scan converter?
a) enhance boundaries between reflectors
b) improve the signal to noise ratio
c) limited dynamic range of the scan converter
d) small matrix size of the scan converter
c) limited dynamic range of the scan converter
135
Which operator control eliminates low amplitude noise from the B-mode image?
a) power
b) reject
c) write zoom
d) TGC
b) reject
136
Which B-mode operator control allows multiple sequential frames to be added together for display in real time?
a) compression
b) reject
c) digital filtering
d) persistence
d) persistence
137
What is the advantage of a high setting for persistence?
a) increased signal to noise ratio
b) improved spatial resolution
c) higher frame rate
d) extended penetration
a) increased signal to noise ratio
138
What is the disadvantage of a high setting for persistence?
a) increased noise content
b) blurring of moving structures
c) loss of contrast resolution
d) reduced penetration
b) blurring of moving structures
139
What does activation of the cine function accomplish?
a) playback of acquired frames stored in a buffer
b) magnification of the field of view
c) automated tracking of fast moving reflectors
d) panoramic field of view
a) playback of acquired frames stored in a buffer
140
What causes phase aberration?
a) variable acoustic velocity along path
b) variable acoustic impedance along path
c) variable attenuation along path
d) borad bandwidth of transmitted pulse
a) variable acoustic velocity along path
141
Which scanning method improves contrast by reducing the contribution of clutter in the B-mode image?
a) spatial compounding
b) coded excitation
c) elastography
d) tissue harmonic imaging
d) tissue harmonic imaging
142
What is the advantage of coded excitation in B-mode imaging?
a) improved axial resolution
b) reduced slice thickness
c) deeper penetration
d) faster frame rates
c) deeper penetration
143
What is the advantage of zone sonography in B-mode imaging?
a) improved axial resolution
b) reduced slice thickness
c) deeper penetration
d) faster frame rates
d) faster frame rates
144
What is a potential application of elastography?
a) contrast angiography
b) tissue characterization
c) destruction of tumors
d) show heart valve motion
b) tissue characterization
145
Which transducer is best suited for 4D ultrasound?
a) linear array
b) phased array
c) 1.5D array
d) matrix array
d) matrix array
146
What is the advantage of the cine loop function in B-mode imaging?
a) reduced transmit power during cine acquisition
b) improved lateral resolution
c) instantaneous review of real-time acquisition
d) faster acquisition frame rates
c) instantaneous review of real-time acquisition
147
What is the advantage of the frequency compounding in B-mode imaging?
a) increase penetration
b) improved contrast resolution
c) emphasize tissue texture
d) all of the above
d) all of the above
148
How is averaging effect enhanced in spatial compounding?
a) frequency filtering
b) additional beam angles
c) borad beam width
d) multiple transmit focal zones
b) additional beam angles
149
What is the effect of harmonic formation on the sinusoidal ultrasound wave?
a) sinusoidal wave at twice the frequency
b) sinusoidal wave at one half the frequency
c) saw tooth waveform
d) no effect
c) sawtooth waveform
150
What is the frequency composition of the echo from a specular reflector after the incident wave has undergone nonlinear propagation?
a) fundamental frequency only
b) second harmonic frequency only
c) harmonic frequencies only
d) both fundamental and harmonic frequencies
d) both fundamental and harmonic frequencies
151
How does the pulse phase inversion method isolate the harmonic frequency?
a) high pass filtering
b) two pulse transmission
c) phase shift of the echo-induced signal
d) rejection control of signal amplitudes
b) two pulse transmission
152
What is the advantage of the pulse phase inversion method isolate the harmonic frequency?
a) narrow bandwidth transmission
b) fast acquisition time
c) high signal to noise ratio
d) higher harmonic fraction in each recieved echo
c) high signal to noise ratio
153
What is the disadvantage of the pulse phase inversion method isolate the harmonic frequency?
a) low penetration
b) subject to motion artifact
c) low signal to noise ratio
d) poor axial resolution
b) subject to motion artifact
154
Where in the ultrasounic field is the intensity of harmonics likely to be the highest?
a) at the transducer face, near the central beam
b) near the central beam, but offset from the transducer
c) near the edge of the ultrasonic field, but offset from the transducer
d) at the transducer face, at the edge of the ultrasonic field
b) near the central beam, but offset from the transducer
155
What signal processing technique reduces the dynamic range of signal levels prior to scan conversion?
a) overall gain
b) log compression
c) gray scale mapping
d) bilinear interpolation
b) log compression
156
What is the image processing technique that translates pixel values to brightness levels in the displayed image?
a) persistence
b) compression
c) gray scale map
d) reject
c) gray scale map
157
Which operator control would change the brightness level of weak reflectors in the displayed image?
a) read zoom
b) scan range
c) gray scale map
d) freeze frame
c) gray scale map
158
What is the purpose of the gray scale map?
a) define the relationship between velocity and brightness
b) define the relationship between acoustic impedance and brightness
c) define the relationship between signal level and brightness
d) define the relationship between attenuation and brightness
c) define the relationship between signal level and brightness
159
At which processing stage does dynamic receive focusing take place?
a) receive beam formation
b) amplification
c) scan conversion
d) gray scale mapping
a) receive beam formation
160
What signal processing technique eliminates low signal levels and redistributes the remaining signal levels throughout the gray scale prior to display?
a) overall gain
b) TGC
c) dynamic range
d) bilinear interpolation
c) dynamic range
161
At which processing stage does bilinear interpolation take place?
a) receive beam formation
b) amplification
c) scan conversion
d) gray scale mapping
c) scan conversion
162
What is the purpose of bilinear interpolation?
a) increase the dynamic range
b) improve image contrast of weak signals
c) assign values to unsampled pixels
d) expand the brightness levels available for display
c) assign values to unsampled pixels
