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SPI > Doppler Pt 1 > Flashcards

Doppler Pt 1 Flashcards

1
Q

occurs when blood clots in vessels

A

thrombosis

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2
Q

narrowing of a blood vessel

A

stenosis

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3
Q

something closed of blocked off

A

occlusion

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4
Q

does occluded artery or thrombosed vein show color?

A

no

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5
Q

___ is a normal cause of turbulence

A

tortuosity

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6
Q

arterial stenosis can lead to

A

post stenotic turbulence

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7
Q

filling in of spectral window on doppler tracing caused by turbulence

A

spectral broadening

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8
Q

pressure gradient = 4 (velocity)^2

A

Bernoulli equation

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9
Q

peak systolic = 3 m/s

peak pressure gradient = ?

A

36 mmHg

pressure gradient = 4 (velocity)^2 = 4 (3)^2 = 36

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10
Q

doppler evaluation provides speed and direction of flow

A

velocity

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11
Q

location where doppler shift is being obtained

A

sample volume

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12
Q

pressure is lowest at

A

stenotic site

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13
Q

increasing threshold ___ the amount of color displayed in slow moving vessels

A

increases

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14
Q

PSV - EDV / PSV

A

resistive index

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15
Q

if EDV = 0, RI =

A

1

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16
Q

reducing sample size improves

A

temporal resolution

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17
Q

changing color map in real time

A

preprocessing

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18
Q

waveform with 2 components of antegrade flow during cardiac cycle

A

triphasic

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19
Q

increased frame rate =

A

more color displayed

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20
Q

flow distal to stenosis

A

reduced doppler shift (velocity), low resistance turbulent waveform, and greater bandwidth

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21
Q

stenosis demonstrates

A

high velocity, higher resistance, and lower pressure

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22
Q

____ can reduce beam width artifact, clutter, and crosstalk

A

increasing wall filter

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23
Q

beam width artifact, clutter, and crosstalk all involve

A

incorrect display of low level doppler shifts

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24
Q

when referring to blood flow volume throughout the body, ____ and ____ are the best answer

A

cardiac function

vessel resistance

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25
Q

if speed of sound in soft tissue increases, doppler shift

A

decreases

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26
Q

FFT requires a minimum of __ samples/cycle to process and produce a _____

A

2

doppler tracing

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27
Q

FFT cannot correctly process a frequency shift greater than

A

1/2 PRF

Nyquist limit, aliasing will occur

28
Q

most systems obtain ___ doppler samples per scan line

A

100-400

29
Q

what is the appearance of an aliasing waveform?

A

wrapping around the baseline

30
Q

to correct spectral doppler wrap around

A

increase PRF to allow proper display of high velocities, BUT use a lower frequency to provide more depth penetration to fully resolve the issue

31
Q

PRF =

A

velocity scale

32
Q

brightness of the reflection on the doppler tracing represents

A

the # of RBCs moving at each velocity displayed

33
Q

lower reflectivity makes blood

A

more difficult to see at greater depths than ST

reason you can see deep vessel with no color flow

34
Q

process to produce color doppler shift info

A

autocorrelation

35
Q

used to produce spectral doppler settings

A

FFT

36
Q

determines direction of flow, either forward or reverse with respect to transducer but does not produce spectral tracing

A

quadrate phase detection

37
Q

unable to detect flow less then 6 cm/s, unable to detect post stenotic turbulence and spectral broadening, and usually underestimates high velocities and over estimates low velocities

A

analog doppler

38
Q

increasing sweep speed will aide in ability to properly

A

trace the contour of the doppler waveform

39
Q

larger packet in color doppler =

A

better flow sensitivity

40
Q

color is assigned to flow based on # of moving RBCs, it is NOT related to velocity of the movement

A

power doppler

41
Q

compares peak to mean velocity throughout 1 cardiac cycle

A

pulsatility index

42
Q

noise can be reduced by

A

decreasing doppler gain, increasing wall filter, or trying another wall outlet

43
Q

used to improve SNR on color image and defined as averaging of previous image frames to produce newest frames

A

persistence

44
Q

highest velocity throughout a stenosis is

A

immediately distal to focal point of stenosis

45
Q

to reduce clutter, ___ color priority

A

decrease

46
Q

reduced sample size = ____ spectral window

A

larger

47
Q

for the best velocity calculation, what must be known?

A

angle between flow and sound beam

48
Q

doppler shift and frequency relationship

A

direct

49
Q

frequency is reduced by 1/2, ___ decrease in detected flow, machine will display ___ velocity

A

50%

same

50
Q

resistance of a vessel is determined by

A

the part it is supplying

51
Q

____ on doppler exam will cause false increase in peak velocity

A

overgaining

52
Q

what is necessary to quantify doppler shift?

A

cos of angle
frequency
speed of sound in ST

53
Q

to eliminate crosstalk

A

lower gain

54
Q

color is not angle dependent when using

A

power doppler

55
Q

anemia affect on blood velocity

A 
increased velocity 
(thinner blood = reduced viscosity = increased velocity)
56
Q

2D imaging = ___ pulse per scan line

Color doppler = ___ pulses per scan line

A

1

3-32

57
Q

power doppler has ___ frame rates than color

A

slower

58
Q

to measure acceleration time

A

place a caliper at the onset of the systolic upstroke and at the early systolic peak

59
Q

measurement used to assess flow in organs, extremities, and through cardiac valves

A

acceleration time

60
Q

radius decreases by 1/2, flow volume

A

decreased by 2^4 (16x)

61
Q

repetitive echoes above the baseline are consistent with

A

electrical interference

62
Q

color doppler displays ___ velocity

A

mean

63
Q

PW displays ___ velocity

A

peak

64
Q

perceived color used to demonstrate direction; reds and blues; determined by direction (+ or -) of the shift

A

color hue

65
Q

brightness of the color displayed; determined by magnitude of the reflection

A

luminance

SPI (3 decks)

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