chapter 4: doppler waveform analysis

Question 1

capabilities of doppler

Answer 1

confirm diagnosis and location of arterial disease

indicate severity of occlusive process

Question 2

limitations of doppler

Answer 2

waveforms can be effected by temperature
uncompensated CHF can dampen waveforms
unable to discriminate stenosis from occlusion
technically dependent

Question 3

patient positioning

Answer 3

supine with extremities at same level as heart
hip externally rotated
knee slightly bent

Question 4

doppler shift

Answer 4

when a wave is reflected from a moving target the frequency of the wave returning is different from the transmitted wave

Question 5

doppler effect occurs with

Answer 5

relative motion between the source and the receiver of the sound

Question 6

in the doppler shift what is the moving target

Answer 6

blood

Question 7

in the doppler shift what is stationary source

Answer 7

transducer

Question 8

types of doppler velocietry

Answer 8

analog

spectral analysis

Question 9

analog

Answer 9

employs a zero crossing frequency meter

displays the signals graphically on a strip chart recorded

Question 10

analog paper speed

Answer 10

25mm/sec

Question 11

zero crossing frequency meter

Answer 11

counts each time the input signal crosses through zero (baseline) within a time span
high frequency waves has many oscillations
low frequency waves have few
machine estimates frequencies and displays them

Question 12

analog dopller velocimetry drawbakcs

Answer 12

noise
less sensitivity
high velocities are underestimated
low velocities over estimated

Question 13

spectral analysis

Answer 13

individual frequencies are displayed by Fast Fourier Transform FFT method

Question 14

spectral analysis is most commonly used

Answer 14

during duplex evaluation

Question 15

spectral analysis display

Answer 15

time on the X (horizontal) axis and frequency shifts on the Y axis (vertical axis)

Question 16

upper extremity doppler is performed on which arteries

Answer 16

subclavian 
axiallary
brachial (at elbow)
radial (thumb side at wrist)
ulnar (5th finger side at wrist)

Question 17

Lower extremity doppler is performed on which arteries

Answer 17

CFA
SFA
popliteal
PTA (medial malleolus)
DPA (top of foot)
Peroneal (lateral malleolus)

Question 18

potential sources of error

Answer 18

improper probe position
probe motion
incorrect angle of incidence
inadequate amount of gel
excessive pressure on the probe
insufficient period of rest before testing

Question 19

a complete arterial exam includes

Answer 19

audible and wave form qualities as well as doppler segmental pressures

Question 20

Normal signals:

Answer 20

triphasic waveform

Question 21

triphasic waveform characteristics

Answer 21

rapid upslope
sharp peak
rapid downstroke
flow reversal
resumption of forward flow

Question 22

examples of triphasic waveforms

Answer 22

UE and LE arteries

Question 23

Abnormal signals

Answer 23

biphasic and monophasic waveforms

Question 24

biphasic waveform characteristics

Answer 24

rapid upslope
sharp peak
fairly rapid downstroke
flow reversal
no resumption of forward flow
can be considered normal in some patients

Question 25

monophasic waveform characteristics

Answer 25

slow upslope rounded peak slow down stroke no reversal

Question 26

a monophasic waveform is often obtained where

Answer 26

proximal to an obstrcution

Question 27

well collateral occlusions can appear similar to

Answer 27

flow distal to a stenosis

Question 28

distal to a stenosis waveforms may appear

Answer 28

monophasic and steady | because of vasodilation of distal vessels due to proximal obstruction

Question 29

subclavian artery signal

Answer 29

high resistance | multiphasic flow

Question 30

proximal occlusion in subclavian artery wil make the signal

Answer 30

more monophasic

Question 31

UE Doppler: Strandness and sumner

Answer 31

describe arteriovenous shunts in skin of fingertips that cause flow patterns in hand to be variable

Question 32

Normal doppler waveform post exercise

Answer 32

pre-exercise wave form qualities are maintained no reverse component usually just pressures obtained post exercise

Question 33

Abnormal doppler waveform post exercise

Answer 33

slow upstroke rounded peak slow downstroke no reverse component

Question 34

absent doppler signals post exercise may indicate

Answer 34

occlusion or pre-occlusive vessel

Question 35

analog doppler is not capable of portraying velocities of less than

Answer 35

6 cm/sec

Question 36

pulsatility index (PI)

Answer 36

calculated by dividing the peak-to-peak frequency difference (P1-P2) by mean average frequency

Question 37

Acceleration time is based on the principle that

Answer 37

proximal arterial obstruction results in slowing of the time interval between the onset of systole to the point of maximum peak

Question 38

An acceleration time of >133 msec indicates

Answer 38

proximal iliac disease

Question 39

inflow disease is

Answer 39

ex: aortoiliac disease | represents blood flowing into the lower extremities

Question 40

outflow disease is

Answer 40

represents blood flow flowing out into the extremities | ex: femoral-popliteal disease