Doppler Pt 1

Question 1

occurs when blood clots in vessels

Answer 1

thrombosis

Question 2

narrowing of a blood vessel

Answer 2

stenosis

Question 3

something closed of blocked off

Answer 3

occlusion

Question 4

does occluded artery or thrombosed vein show color?

Answer 4

no

Question 5

___ is a normal cause of turbulence

Answer 5

tortuosity

Question 6

arterial stenosis can lead to

Answer 6

post stenotic turbulence

Question 7

filling in of spectral window on doppler tracing caused by turbulence

Answer 7

spectral broadening

Question 8

pressure gradient = 4 (velocity)^2

Answer 8

Bernoulli equation

Question 9

peak systolic = 3 m/s

peak pressure gradient = ?

Answer 9

36 mmHg

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

Question 10

doppler evaluation provides speed and direction of flow

Answer 10

velocity

Question 11

location where doppler shift is being obtained

Answer 11

sample volume

Question 12

pressure is lowest at

Answer 12

stenotic site

Question 13

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

Answer 13

increases

Question 14

PSV - EDV / PSV

Answer 14

resistive index

Question 15

if EDV = 0, RI =

Answer 15

1

Question 16

reducing sample size improves

Answer 16

temporal resolution

Question 17

changing color map in real time

Answer 17

preprocessing

Question 18

waveform with 2 components of antegrade flow during cardiac cycle

Answer 18

triphasic

Question 19

increased frame rate =

Answer 19

more color displayed

Question 20

flow distal to stenosis

Answer 20

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

Question 21

stenosis demonstrates

Answer 21

high velocity, higher resistance, and lower pressure

Question 22

____ can reduce beam width artifact, clutter, and crosstalk

Answer 22

increasing wall filter

Question 23

beam width artifact, clutter, and crosstalk all involve

Answer 23

incorrect display of low level doppler shifts

Question 24

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

Answer 24

cardiac function

vessel resistance

Question 25

if speed of sound in soft tissue increases, doppler shift

Answer 25

decreases

Question 26

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

Answer 26

2 | doppler tracing

Question 27

FFT cannot correctly process a frequency shift greater than

Answer 27

1/2 PRF | Nyquist limit, aliasing will occur

Question 28

most systems obtain ___ doppler samples per scan line

Answer 28

100-400

Question 29

what is the appearance of an aliasing waveform?

Answer 29

wrapping around the baseline

Question 30

to correct spectral doppler wrap around

Answer 30

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

Question 31

PRF =

Answer 31

velocity scale

Question 32

brightness of the reflection on the doppler tracing represents

Answer 32

the # of RBCs moving at each velocity displayed

Question 33

lower reflectivity makes blood

Answer 33

more difficult to see at greater depths than ST | reason you can see deep vessel with no color flow

Question 34

process to produce color doppler shift info

Answer 34

autocorrelation

Question 35

used to produce spectral doppler settings

Answer 35

FFT

Question 36

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

Answer 36

quadrate phase detection

Question 37

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

Answer 37

analog doppler

Question 38

increasing sweep speed will aide in ability to properly

Answer 38

trace the contour of the doppler waveform

Question 39

larger packet in color doppler =

Answer 39

better flow sensitivity

Question 40

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

Answer 40

power doppler

Question 41

compares peak to mean velocity throughout 1 cardiac cycle

Answer 41

pulsatility index

Question 42

noise can be reduced by

Answer 42

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

Question 43

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

Answer 43

persistence

Question 44

highest velocity throughout a stenosis is

Answer 44

immediately distal to focal point of stenosis

Question 45

to reduce clutter, ___ color priority

Answer 45

decrease

Question 46

reduced sample size = ____ spectral window

Answer 46

larger

Question 47

for the best velocity calculation, what must be known?

Answer 47

angle between flow and sound beam

Question 48

doppler shift and frequency relationship

Answer 48

direct

Question 49

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

Answer 49

50% | same

Question 50

resistance of a vessel is determined by

Answer 50

the part it is supplying

Question 51

____ on doppler exam will cause false increase in peak velocity

Answer 51

overgaining

Question 52

what is necessary to quantify doppler shift?

Answer 52

cos of angle frequency speed of sound in ST

Question 53

to eliminate crosstalk

Answer 53

lower gain

Question 54

color is not angle dependent when using

Answer 54

power doppler

Question 55

anemia affect on blood velocity

Answer 55

``` increased velocity (thinner blood = reduced viscosity = increased velocity) ```

Question 56

2D imaging = ___ pulse per scan line | Color doppler = ___ pulses per scan line

Answer 56

1 | 3-32

Question 57

power doppler has ___ frame rates than color

Answer 57

slower

Question 58

to measure acceleration time

Answer 58

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

Question 59

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

Answer 59

acceleration time

Question 60

radius decreases by 1/2, flow volume

Answer 60

decreased by 2^4 (16x)

Question 61

repetitive echoes above the baseline are consistent with

Answer 61

electrical interference

Question 62

color doppler displays ___ velocity

Answer 62

mean

Question 63

PW displays ___ velocity

Answer 63

peak

Question 64

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

Answer 64

color hue

Question 65

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

Answer 65

luminance