Doppler Waveform Analysis Flashcards
Doppler waveform analysis uses CW Doppler with an angle of insonation of
45-60°
qualitative or quantitative?
Doppler waveform analysis - FFT and analog waveforms
qualitative
normal Doppler waveform
triphasic
rapid systolic upstroke, sharp peak
rapid systolic downstroke
late systolic flow reversal
forward diastolic flow
abnormal but often considered normal waveform
biphasic
rapid upstroke, sharp peak
slight slowed systolic downstroke
late systolic flow reversal
no forward diastolic flow
abnormal waveform
monophasic
delayed systolic upstroke, rounded peak
slowed systolic downstroke
no systolic flow reversal
qualitative or quantitative
Doppler waveform analysis - FFT Spectral analysis (PI and AT)
quantitative
FFT spectral analysis is typically used at the ___ to detect the presence of ___
CFA
inflow (aorta/iliac) disease
Pulsatility Index (PI) =
PI = (P1-P2) / mean frequency
pulsatility index
normal
abnormal
normal > 4.0
abnormal < 4.0 (consistent with a 60% stenosis proximal to the sample)
systolic acceleration time (AT)
normal
abnormal
normal < 133ms
abnormal > 133ms (proximal obstruction)
poorly collateralized proximal occlusion
___ systolic upstroke
___ velocity
___ resistance
very delayed systolic upstroke
low velocity
low resistance
inflow vs outflow
inflow - blood flowing into the LE (aorta/iliac disease)
outflow - blood flow going out into the extremity (femoral/popliteal disease)
normal Doppler waveform post-exercise
upstroke should be similar to the resting baseline
may exhibit loss in systolic flow reversal and more diastolic forward flow
absent signals post-exercise (present pre-exercise) may suggest ___
complete or near occlusion
analog Doppler is not sensitive to velocities less than ___
6 cm/sec
normal flow in subclavian, axillary, brachial arteries is
high resistance, multiphasic
waveforms at the wrist tend to be ___
more variable
lower resistance can be present in a relaxed, warm patient
Doppler waveform recorder stylus paper speed
25 mm/sec
troubleshooting
- recorder stylus not recording
- recording stylus stuck
- “60 cycle” noise or interference
- recorder stylus not recording - check proper test and transducer are selected
- recording stylus stuck - reset, re-center control
- “60 cycle” noise or interference - decrease gain, reset, use different power outlet
