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SPI Click to Learn > Doppler Click to Learn Part 1 > Flashcards

Doppler Click to Learn Part 1 Flashcards

1
Q

Which of the following is inversely related to the doppler shift

A. number of red blood cells
B. speed of the red blood cells
C. sine of the angle between the flow and the detector
D. speed of the sound in tissue

A

D

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2
Q

Which of the following will increase the display of color doppler information on the image of a superficial mass

A. decreased sensitivity
B. increased probe frequency
C. increased rejection
D. decreased threshold

A

B

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3
Q

The number of red blood cells in a doppler sample is directly related to

A. size of the spectral window
B. amount of stenosis present at the sample site
C. brightness of the waveform displayed
D. peak velocity of the flow

A

C

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4
Q

According to the bernoulli principle, where will you find the lowest pressure in a vessel with a stenosis

A. at the site of stenosis
B. distal to the stenosis
C. in the collateral vessels
D. proximal to the stenosis

A

A

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5
Q

Autocorrelation calculates the _______ of flow for color doppler flow display

A. doppler shift
B. peak velocity
C. resistive index
D. mean velocity

A

D

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6
Q

_____ is defined as the time from onset of systole to the time peak systole occurs

A. SPL
B. acceleration time
C. velocity time interval
D. resistive index

A

B

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7
Q

How do you adjust your technique to reduce or eliminate cross talk on a doppler tracing

A. use the same approach and incident angle but use a CW non-imaging probe
B. turn down the doppler gain
C. Use a smaller sample size
D. increase the PRF

A

B

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8
Q

Which of the following is a limitation of power doppler

A. inability to display flow velocities greater than 150 cm/s
B. only detects flow moving toward the probe
C. has slower frame rates than color doppler
D. inability to display flow velocities less than 10 cm/s

A

C

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9
Q

Which of the following correctly describes a normal doppler waveform of an artery from the lower extremity

A. the triphasic waveform never demonstrates a retrograde flow component during the cardiac cycle
B. there will be a low resistance, monophasic waveform with a small amount of flow reversal in distole
C. the triphasic waveform will have two components of normal retrograde flow during the cardiac cycle
D. the triphasic waveform will have two components of antegrade flow during the cardiac cycle

A

D

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10
Q

A reynolds number greater than ____ indicates turbulent flow on _____ evaluation

A. 500, color doppler
B. 500, PW doppler
C. 2000, PW doppler
D. 2000, color doppler

A

D

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11
Q

The doppler tracing of the flow in a vessel 1cm distal to a stenosis will demonstrate _____ than at the stenosis

A. greater resistance
B. more laminar flow
C. greater bandwidth
D. greater doppler shift

A

C

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12
Q

While scanning an obese patient, you apply color doppler to the aorta. When you adjust the placement of the box, there is a delay between your adjustment and the box moving on the image. How can you correct this

A. activate write magnification over the area of interest
B. increase the sample size
C. switch to a higher frequency probe
D. activate read magnification over the area of interest

A

A

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13
Q

If there is no diastolic flow demonstrated on a doppler tracing of the arcuate artery of the upper pole of the right kidney, what will the resistive index be

A. unable to calculate the RI, not enough information given
B. 1.0
C. 0
D. 0.5

A

B

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14
Q

You are evaluating an obese patient with a known abdominal aortic aneurysm. While using color Doppler to assess flow within the aortic aneurysm, minimal flow is detected in the anechoic lumen. You decrease the color scale and increase the color gain but there is no improvement. Which of the following adjustments will improve the color display on this exam

A. increase color sample size
B. increase the color threshold
C. switch from a 4MHz curved array to a 4MHz linear array
D. decrease the color threshold

A

B

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15
Q

When you adjust the doppler PRF, you adjust the ____ control on the system

A. velocity baseline
B. threshold
C. sensitivity
D. velocity scale

A

D

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16
Q

Which statement regarding the differences between pulsed and continuous wave doppler is NOT correct

A. CW doppler tracings do not display a spectral window with any flow type
B. PW doppler is limited in detection of a doppler shift by the PRF of the system but CW doppler is not
C. CW doppler offers significantly improved range resolution
D. PW doppler requires one PE crystal, while CW doppler uses two crystals

A

C

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17
Q

Blood flow at a focal stenosis will demonstrate

A. increased resistance
B. increased viscosity
C. increased pressure
D. decreased velocity

A

A

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18
Q

_______ is used to improve the signal to noise ratio on a color doppler image and is defined as the averaging of previous image frames to produce the newest frame

A. variance color display
B. persistence
C. harmonic imaging
D. threshold settings

A

B

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19
Q

Which of the following parameters is displayed on the y-axis on a doppler tracing

A. speed
B. frequency shift
C. motion
D. time

A

B

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20
Q

If the peak pressure gradient in a vessel is 36mmHg, what is the velocity of the flow

A. 1 cm/s
B. 3 m/s
C. 2 cm/s
D. 4 cm/s

A

B, bernouli equation is used to calculate the peak pressure gradient. PPG=4 x velocity^2. If the peak pressure gradient is 36, divide by 4=9, the square root of 9 is 3

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21
Q

Blood flow volume changes in the body are mainly controlled by what two factors

A. cardiac function and peripheral resistance
B. viscosity and friction
C. vessel radius and resistance
D. cardiac function and vessel radius

A

A

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22
Q

When evaluating a focal stenosis of an artery, where should you place the cursor to obtain the highest velocity related to the stenosis

A. immediately proximal to the focal point of the stenosis
B. immediately distal to the focal point of the stenosis
C. 2cm distal to the stenosis
D. at the narrowest point in the vessel or immediately distal to the focal point of the stenosis

A

D

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23
Q

You identify a possible stenosis in the carotid artery and you switch the color map from velocity to variance while scanning. Which of the following describes what you just did

A. changed the preprocessing settings
B. changed the processing from fast fourier transformer to autocorrelation
C. changed the processing from autocorrelation to fast fourier transformer
D. changed the post processing settings

A

A

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24
Q

How do you correct beam width artifact on a doppler tracing

A. decrease the PRF
B. increase the incident angle of the doppler cursor
C. decrease the sweep speed
D. use a smaller sample size

A

D

25
Q

If the peak systolic velocity is 3 m/s, what is the peak pressure gradient

A. 9mm/Hg
B. 36mmHg
C. 27 mmHg
D. 18mmHg

A

B, bernoulli equation: pressure gradient= 4(velocity^2)= 4(3)(3)=36mmHg

26
Q

Which of the following doppler measurements requires the waveform to be traced from start of systole to the end of diastole

A. resistive index
B. pulsatility index
C. S/D ratio
D. acceleration time

A

B

27
Q

Which of the following is an abnormality that would lead to an increase in the reynolds number

A. occlusion of an artery
B. thrombosis of a vein
C. stenosis of the vessel
D. tortuous vessel

A

C, an occluded artery and thrombosed vein would not demonstrate any flow on color doppler evaluation. Tortuosity is a normal cause for turbulence in a vessel. Arterial stenosis is a vascular abnormality that can lead to significant post stenotic turbulence seen on the color coppler image

28
Q 
Increasing the spectral doppler sample size will increase the \_\_\_\_\_\_
A. spectral broadening
B. sweep speed
C. doppler shift
D. size of the spectral window
A

A

29
Q

If the radius of a bloow vessel decreases by 50% what happens to the flow volume

A. decreases by 4x
B. decreases by 50%
C. decreases by 2x
D. decreases by 16x

A

D, radius decreases by 1/2, flow volume decreases by 2 to the fourth power. if the vessel radius decreased by 1/3, the flow volume decreases by 3 to the fourth power

30
Q

What is the primary factor that determines the resistance characteristics of the arterial signal displayed by PW doppler

A. origin of blood
B. branch number
C. vessel course and location
D. part it is supplying

A

D

31
Q

Overgaining on an US exam can cause

A. increased posterior shadowing
B. overestimation of doppler velocity
C. underestimation of arterial stenosis
D. blood to appear anechoic

A

B

32
Q

What is the cosine of 0 degrees

A. 0
B. 0.5
C. 0.7575
D. 1

A

D, 0=1, 60=0.5, 90=0

33
Q

What is the twinkle artifact

A. varied brightness of vascular calcifications causes a twinkling effect on 2D
B. mosaic colors displayed in a linear pattern posterior to a dense object, such as a renal stone
C. describes the color display seen as urine is entering the bladder during real time imaging
D. thin line of reverberation artifact that is caused by calcium deposits in the renal parenchyma

A

B

34
Q

If the transmitted frequency is 5MHz and the reflected frequency 4.9975 MHz, how will the doppler shift be displayed

A. on top of the baseline
B. unable to determine without a second relative doppler shift for comparison
C. with a peak velocity of 25 m/s
D. under the baseline

A

D, doppler shift= reflected frequency-transmitted frequency. this makes the doppler shift negative which makes the shift below the baseline

35
Q

Which of the following will lead to more color displayed in real time in the abdominal aorta

A. increase sample size
B. decrease color threshold
C. decrease color gain
D. increase frame rate

A

D

36
Q

The brightness of the reflection on the doppler tracing represents ______

A. the frequency of the reflection
B. the spatial pulse length of the reflection
C. the time duration of the reflection
D. the number of red blood cells moving at each velocity displayed

A

D

37
Q

Which of the following statements correctly describes power doppler

A. offers the highest temporal resolution of all ultrasound imaging techniques
B. color is assigned to the doppler shift based on the number of moving red blood cells
C. demonstrates mean flow velocities of an red blood cell in the sample
D. color is assigned to the doppler shift based on the velocity of moving red blood cells

A

B

38
Q

What is the average nyquist limit for a 5MHz CW doppler probe

A. 10kHz
B. 7kHz
C. 15kHz
D. none of the above

A

D, CW probe is not limited by the PRF and nyquist limit because the beam is not pulsed

39
Q

Which of the following system control adjustments will increase the amount of color doppler that is superimposed over the 2D image

A. decreased persistence and increased wall filter
B. increased wall filter and increased threshold
C. decreased threshold and persistence
D. increased threshold and increased persistence

A

D

40
Q

Which of the following will increase spectral broadening on the image

A. more laminar flow
B. increased sample volume size
C. increased PRF
D. increased wall filter

A

B

41
Q

The ______ the pulse packet used in color doppler, the better the flow sensitivity

A. larger
B. more perpendicular
C. smaller
D. more parallel

A

A

42
Q

No flow is detected while performing a color doppler evaluation of a normal patent vein. What will improve the color display

A. increase the PRF
B. increasing angle of insonation
C. increase the sample size
D. increase the color packet size

A

D, color packet refers to the number of scan lines of info in each sample taken, the more lines in the sample the better the display

43
Q

Which of the following is not a variable necessary to quantify the doppler shift

A. speed of sound in tissue
B. sine of the doppler angle
C. transducer frequency
D. all of the above are necessary for calculation of the doppler shift

A

B, cosine is used, not sine

44
Q

The magnitude of the doppler shift in color doppler determines

A. the color threshold
B. the color luminance
C. the peak velocity of the flow displayed as color
D. the color hue

A

B, luminance- brightness of the color displayed, determined by the magnitude of the doppler shift

45
Q

Which of the following correctly describes a CW doppler evaluation

A. CW doppler transducer contain a single element to constantly transmit sound
B. the angle of incidence does not affect the velocity evaluation using CW doppler because you are not evaluating the vessel at a specific depth
C. CW doppler tracing will not demonstrate a spectral window
D. CW doppler is most useful with low velocity flow that is undetectable on PW doppler systems

A

C

46
Q

What system control can reduce the appearance of clutter on a color doppler image

A. increasing persistance
B. decreasing color scale
C. decreasing color priority
D. increasing color threshold

A

C

47
Q

The best obtainable angle of insonation for vascular evaluation that is most commonly used to provide doppler shift information is _____ degrees

A. 0
B. 45
C. 60
D. 90

A

C

48
Q

Which of the following correctly describes a limitation of the FFT

A. cannot correctly process a frequency shift that is less than one half of the PRF
B. cannot process more than two samples per cycle
C. cannot correctly process a frequency shift that is less than half the transducer frequency
D. requires a minimum of two samples per cycle to process and produce a doppler tracing

A

D

49
Q

Which of the following artifacts can NOT be corrected by increasing the wall filter settings

A. clutter artifact
B cross talk artifact
C. aliasing artifact
D. beam width artifact

A

C, the wall filter will not reduce the appearance of aliasing with high velocity/turbulent flow

50
Q

The ability to see flow in a very deep vessel is limited by the fact that

A. blood moves at the same speed as the surrounding tissues
B. blood is less reflective than soft tissues
C. blood has a very low attenuation rate
D. blood moves at a faster rate than the surrounding tissues

A

B

51
Q

Overgaining on an US exam can cause _______

A. overestimation of doppler velocity
B. underestimation of arterial stenosis
C. blood to appear anechoic
D. increased posterior shadowing

A

A, this will cause a false increase in the peak velocity of the flow

52
Q

How do you adjust your technique to reduce or eliminate cross talk on a doppler tracing

A. use a smaller sample size
B. use the same approach and incident angle but use a CW non imaging probe
C. increase the PRF
D. turn down the doppler gain

A

D

53
Q

The doppler tracing of the flow in a vessel 1cm distal to a stenosis will demonstrate _______ than at the stenosis

A. greater bandwidth
B. greater resistance
C. more laminar flow
D. greater doppler shift

A

A

54
Q

Which of the following correctly describes power doppler

A. much more sensitive to higher flow velocities than color doppler
B. color is assigned based on the size of red blood cells moving in a location
C. allows evaluation of approximate flow velocity
D. color display is not angle dependent

A

D

55
Q

What can be done to reduce color flash

A. increase color persistence
B. increase color gain
C. reduce color gain
D. increase color threshold

A

C

56
Q

If there is no diastolic flow demonstrated on a doppler tracing of the arcuate artery of the upper pole of the right kidney, what will the resistive index be

A. unable to calculate the RI, not enough information given
B. 0.5
C. 0
D. 1.0

A

D

57
Q

How do you adjust your technique to reduce or eliminate cross talk on a doppler tracing

A. increase the PRF
B. use the same approach and incident angle but use a CW non imaging transducer
C. use a smaller sample size
D. turn down the doppler gain

A

D

58
Q

Blood flow volume changes in the body are mainly controlled by what two factors

A. cardiac function and vessel radius
B. viscosity and friction
C. vessel radius and resistance
D. cardiac function and peripheral resistance

A

D

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