Vascular technology Doppler waveform analysis

33 terms by nadejbp 

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Doppler waveform analysis capabilities include

indicating the severity of the occlusive process can be used in combination with segmental pressures

Limitations to doppler waveform analysis include____

*patients with casts or bandages
*waveform affected by temp
*CHF may result in dampened waveform
unable to discriminate STENOSIS from OCCLUSION; technically dependent test.

___ is a type of velocimetry that employs a zero-crossing frequency meter to display the signals graphically on a strip chart recorder

analog

____ estimates frequencies present in the reflected signal and displays them. The circuitry counts ea time the input signal crosses through the baseline within a time span.

zero crossing detector

with zero-crossing detection ___ frequency waves have many oscillations and ___ frequency waves have few.

high; low

___ is a type of velocimetry that uses individual frequencies displayed by the FFT method

spectral analysis

In spectral analysis, the horizontal x axis represents___

time

In spectral analysis, the vertical y axis represents___

frequency shifts

the advantage of spectral analysis is that it is ___

free of the analog recording drawbacks

For doppler waveform analysis, use an ___ frequency probe

8 - 10 MHz

an upper extremity arterial doppler velocity wave form exam includes ____ arteries

subclavian, axillary, brachial at elbow antecubital fossa, radial thumb side at wrist, ulnar at wrist

a lower extremity arterial doppler velocity wave form exam includes ___ arteries

CFA, SFA popliteal, PTA medial malleolus, DPA top of foot, and peroneal if necessary at lateral malleolus

A qualitatively normal wave form is __ while abnormal wave forms may be __ or __

triphasic, biphasic, monophasic

a ____ signal is often obtained proximal to an obstruction, with no diastolic flow.

monophasic/dampened pulsatile

Distal to an obstruction, the signal is _____

monophasic, more steady

___ can appear similar to flow distal to a stenosis

well collateralized occlusion

when there is vasodilation of distal vessels assoc with a proximal obstruction __ occurs

reduction in the pulsatility causing the signals to have lower resistant (steady) flow quality

Normal Doppler waveform Post exercise will have what type of appearance

pre exercise wave form qualities are maintained and/or augmented
*no reverse component
Remember that, usually just segmental pressures obtained post exercise describes

Abnormal Doppler waveform Post exercise will have what type of appearance

*slow upstroke with more rounded peak
*slow downstroke
no reverse component

absent doppler signals that may suggest occlusion or pre-occlusive vessel is known as___.

string sign

analog doppler is not capable of protraying velocities of less than ____.

6 cm/sec

Quantitative interpretation is used with___

spectral analysis

qualitative interpretation is used with__

continuous wave

___ helps to differentiate inflow (aorto-iliac) disease from outflow (S femoral) disease

acceleration time

___ is based on the principle that proximal arterial obstruction results in a slowing of the time interval between the onset of systole to the point of maximum peak.

acceleration time

an acceleration time of greater than____ suggests presence of proximal iliac disease

133 m/sec

PI = P1 - P2/ mean frequency

Pulsatility index equation

what are some of the drawbacks of using Analog vs Spectral analysis for obtaining doppler waveform analysis

noise high velocities underestimated
less sensitivity low velocities overestimated

spectral analysis free of many of the analog recording drawbacks

how do you obtain the calibration of doppler waveform on the analog system

most equipment does a self calibration when the system is activated

The circuitry in analog _____

zero crossing frequency meter
how many times the input signal crosses through zero (the baseline) w/n a time span

spectral analysis display ___ on the horizontal axis

time

spectral analysis display ___ on the vertical axis

frequency shifts

List some the potential source of technical error when performing doppler waveform analysis

*******Incorrect angle of incidence
Improper probe position
inadvertent probe motion
Inadequate amount of gel
Excessive pressure on the Probe tip
Insufficient period of rest before testing

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