問題一覧
1
to which acoustic variable is penetration depth inversely related?
A) frequency
2
what is dynamic aperture?
C) aperture that increases with increasing focal length
3
which imaging mode requires a broadband transducer
B) pulse wave Doppler
4
what is the Doppler shift frequency?
B) difference between the transmitted ultrasound frequency, and the received ultrasound frequency
5
what is the potential effect of increasing the pulse repetition frequency (PRF)
A) depth ambiguity
6
what is an advantage of using pulse wave Doppler compared to continuous wave Doppler
B) ability to select sample depth
7
what affects the beam width in the near field
D) transducer aperture
8
what is the advantage of using pulse wave Doppler versus continuous wave Doppler?
D) provides depth specificity
9
which parameter is target group C evaluating based on the image
D) horizontal distance accuracy
10
in this image which target group is used evaluate dead zone
A
11
which ultrasound parameter directly affects an ultrasound beams intensity
C) output power
12
The center frequency of a transducer depends primarily upon which characteristics of the crystal
D) thickness
13
which factor limits image frame rate?
A) fat
14
which term describes the averaging together of scan lines from multiple angles to create one image
D) spatial compounding
15
which variable can cause an acoustic shadow artifact
A) small acoustic impedance mismatch
16
what does coded excitation improve in addition to penetration
B) signal to noise ratio
17
how is lateral resolution determined for a pulse echo system using a tissue mimicking test object
A) by observing spaces between reflectors perpendicular to the beam
18
which variable caused the color change from blue to red of the vessel in this image
A) change in vessel direction
19
which artifact is indicated by the arrows in this image
C) comet tail
20
which control improves the effects of attenuation
D) time gain compensation
21
which Doppler angle to flow results in the greatest absolute Doppler shift
A) 0°
22
what term describes blood flow changes in response to respiration
A) phasic
23
an increase in which parameter will improve the accuracy of velocity measurements with autocorrelation
B) packet size
24
which harmonic imaging how does echo frequency relate to transmitted frequency
C) twice the transmitted frequency
25
which change would minimize the artifact observed in this image, assuming the pulse repetition frequency is at its maximum limit
B) adjust the baseline
26
which parameter is most likely to affect spatial resolution
D) depth of visualization
27
which imaging modality can provide the most accurate measurement of tumor volume
B) B mode
28
according to ALARA guidelines which parameter should be minimized
A) transmit power
29
what is demonstrated in this image produced by a linear ray transducer placed on a uniform tissue mimicking phantom
C) transducer crystals are damaged
30
what is the distance to the interface if the round-trip time for soundwave is 39 microseconds
3cm
31
which signals are eliminated by the wall filter in a spectral Doppler display
low frequency, low amplitude
32
at minimum, what is required when documenting a pathology discovered during an examination
two images demonstrating the same pathology from different scan planes
33
if the diameter of sound beam is half by focusing what happens to the intensity
increased by two times
34
which parameters would change on a phantom test if the spatial pulse length were made longer?
A) axial resolution
35
if the ultrasound machine comes in contact with a patient spotted fluids what should be done?
B) use an approved disinfectant solution to clean it
36
which parameter is most related to cavitation tissue?
B) pressure
37
which interface will cause the maximum reflection of the incident sound beam?
B) soft tissue/bone
38
acoustic enhancement occurs distal to what
D) weakly attenuating structure
39
as the pressure amplitude of the ultrasound doubles, what happens to the wavelength
D) unchanged
40
what is the period of a 5 MHz ultrasound wave
B) 0.2 ms
41
what limits diagnostic application at higher frequency
B) tissue penetration
42
what is the function of a lens on a transducer?
A) focus the beam
43
what would improve axial resolution?
D) increase the transducer frequency
44
what is true of the far field
D) sound beam diverges
45
what improves lateral resolution?
A) decreasing the beam width
46
which statement is true for a linear phased array transducer
B) elements are all fired nearly simultaneously
47
which artifact is commonly seen with cystic masses due to the finite dimensions of the ultrasound beam
D) slice thickness
48
which technique utilizes frequency modulation of the transmitted pulse to improve signal-to-noise ratio
C) coded excitation
49
what is varied to implement apodization
A) voltage applied to each element
50
what will produce no Doppler shift at a receiver?
A) source and receiver moving at the same speed and direction
51
which mode requires two elements mounted side-by-side
D) continuous wave Doppler
52
when employing a tissue mimicking phantom the depth at which echoes are no longer detected is an indicator of what
C) sensitivity
53
what enhances the transmission of ultrasound energy between the transducer and the skin
A) the transducer matching layer
54
which technique increases the sharpness of high contrast boundaries
A) edge enhancement
55
which is most appropriate action for the sonographer to take when receiving a verbal order for an exam?
A) deny performance of the exam until a written request is received
56
which setting of ultrasound system gives the sonographer the ability to display both strong and weak echoes
A) dynamic range
57
what is the benefit of using contrast agents?
B) increased amplitude of returning Doppler signals
58
A soundwave propagates fastest through which substance
A) bone
59
when the focal point in a B mode image is electronically changed which type of focusing is used
C) dynamic
60
when a fluid is flowing at a slow and constant rate within a long tube having a uniform diameter, what is the nature of the flow?
C) laminar
61
what causes range ambiguity artifacts
C) PRF too high
62
What is the round-trip time in soft tissue for an echo from a reflector at depth of 1 cm
C) 13 usec
63
which variable decreases the number of acoustic lines per frame is increased without changing its maximum depth
B) frame rate
64
frequency compounding improves image quality by doing what?
C) reducing speckle
65
What is the most common cause of localized vertical nonuniformity in a real time B mode image
A) improper TGC‘s
66
what is the cause of the black region in the center of the vessel seen in this image?
C) incident angle
67
what is increased if the pulse duration is decreased?
C) frame rate
68
what is the Nyquist limit if a pulse wave Doppler instrument has a pulse repetition frequency of 16 kHz
C) 8 kHz
69
what caused the color pattern demonstrated in the artery indicated by the arrow in this image
B) aliasing
70
which adjustment should be made to avoid the aliasing displayed on this spectral Doppler image seen on spectral analysis
D) decrease the transducer frequency
71
if red blood cells are approaching a 5 MHz Doppler transducer at a speed of 75 cm/s what is the approximate received Ultrasound frequency
C) 5,005 kHz
72
which condition must be present for refraction to occur
C) difference in tissue prop speed
73
The thermal index is most affected by which type of interaction between sound and tissue
B) absorption
74
in an unfocused transducer, which is the region between the transducer face and the point where the beam diverges
C) far field
75
what is this artifact?
C) reverberation
76
how do you fix this?
D) increase the color scale
77
which way is the blood flowing
B) left to right