Doppler Waveform Analysis Flashcards by Sarah Van Acker

what are the capabilities of physiologic testing

diagnosis aprox location & severity of arterial occlusive disease
gives functional information
does not discriminate between stenosis or complete occlusion

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limitations of physiologic testing

cast/bandages
ambient temp affects waveform quality 
CHF results in dampened WF
cannot be specific for stenosis or occlusion 
tech dependent and often difficult test

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Patient position during test is important during what part

sentimental pressures due to hydrostatic pressures

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other positions besides supine for physiologic testing

rt / lft lateral decubitus

prone

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what is the Doppler effect

blood is moving target , transducer is stationary

wave is reflected from moving target, frequency of wave is received as different (that difference is doppler shift) from the transmitted frequency

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The doppler effect occurs with ______ motion between the ____ and the _____ of sound

relative motion

between the source and the receiver of sound

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with continuous wave Doppler one crystal is ______sending ultrasound while the other is _________receiving reflected waves

continuously

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the reflected frequency can be higher or lower depending on the transmitted frequency depending on the direction of flow (T/F)

True

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two types of velocimetry are _______ and _____

zero crossing frequency meter - analog system

FFT fast fourier transform - duplex system (digital)

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what is the paper speed set on zero crossing frequency meter

25mm/sec

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high freq waves have ____oscillations

many

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low freq waves have _____oscilations

few

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zero crossing freq meter counts how many times the _____ crosses over the ______

oscillations cross over the baseline

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direction of blood flow _____with cardiac cycle

varies

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machine estimates _______ present in _____ _____ and displays them

frequencies

reflected signals

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what are drawbacks of zero crossing frequency meter

noise 
less sensitivity (estimation)

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when system is activated __________ is done

self calibraration

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important to remember about zero crossing frequency meter system ??????

It averages out the reflected frequencies

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what does the y and x axis represent in the interpreting the zero crossing frequency meter and the FFT spectral analysis system

y is distance (meters) of frequency shifts

x is time

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Doppler effect: when wave is reflected from a moving target, the reflected freq is diff from transmit freq. The ____ of that change is ______proportional to the speed and direction of _________

magnitude
directly proportional
the moving target

it is proportional to the speed and direction of flow

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magnitude refers to

speed at which an object is moving or its size

Doppler shift formula and relationships

change in frequency =
2 x transmit freq MHz x RBC freq cm/sec x Cos angle of ultrasound beam and flow direction
/
the speed of sound 1540 m/sec

what MHz Doppler probe is used for waveform Doppler analysis of extremities

8-10 MHz

what sites are doppler waveforms recorded on upper etremity studies
5

subclav a
ax a            
Brachial a     @anticubital fossa 
Radial a           @wrist 
Ulnar a             @wrist

doppler velocity waveforms are recorded from the following arteries bilaterally 6

``` CFA SFA Pop A PTA (medial malleolus) DPA (top of the foot) Peroneal (if necessary ) (lateral malleolus) ```

with CW analysis what three things are combined for interpretation

waveforms audible and visual qualities + segmental pressures

CW potential sources for error | 5

``` insufficient period of rest before test excessive pressure on probe tip incorrect angle of incidence incorrect probe positron inadequate amount of gel ```

qualitative interpretation CW triphasic WF characteristics of UE and LE arteries 5

``` rapid upstroke sharp peak rapid downstroke flow reversal resumption of forward flow ```

biphasic WF characteristics of UE and LE arteries | 5

``` rapid upstroke sharp peak fairly rapid down stroke flow reversal * no resumption of forward flow ```

monophasic WF characteristics of UE and LE arteries | 4

slow upstroke rounded peak slow downstroke no reversal

deterioration in signal quality from _____ ______ to the _____ as well as deterioration from _______ _____ should be checked out when preforming CW doppler exam

from one level to the next | from previous tests

monophasic/pulsatile signal is often obtained _____ to an obstruction

proximal

vasodialation of the _____ vessels often occur with ____obstruction which reduces the _______ of the WF and causes the signals to have lower resistant _____ flow quality

distal vessel vasodilation occurs with proximal obstruction reducing the pulsitility & causes lower resistant steady flow quality

well collateralilzed occlusions can appear similar to flow distal to ___________

a stenosis

Subclavian artery signal should look

high resistant multiphasic

flow patterns in hand are ________

variable may have lower resistant signals that can be

Doppler waveforms post excercize: | Normal should appear

pre excercize wave form qualitites are maintained | may be augmented and contain no reverse component because of dialation of distal vascualar bed

Doppler waveform characteristics post excersize | Abnormal

rounded peak, no reverse component

Absent doppler signals may suggest __________ or _____ ______ vessel

occlusion or pre-occlusive vessel

pre occlusive vessle waveform nick name

string sign

the string sign on CW analog format will appear as

absent signal

Analog Doppler is not capeable of portraying velocities of less than

6cm/sec

Trouble shooting- | what should you do to get rid of noise

increase filter turn down gain turn machine off and on

Trouble shooting - | what do you do if the stylus is stuck

re-set or re -center

Trouble shooting | what do you do if the stylus is not recording

make sure that proper test selection and probe type is selected

what is inflow disease and what is a common type

inflow represents blood flowing into the lower extremities | Aorto-iliac disease

what is outflow disease and what would be an example

`blood going out into the extremities | femoral popliteal disease

what is pulsatililty index (PI)

peak -to-peak frequency difference systole to systolic flow reversal (P1 - P2)/ Average cardiac frequency higher number is gen. indicative of disease sometimes used the the CFA

(AT) Acceleration time measures what

onset of systole to max peak

what causes a slowing in the time interval between the onset of systole & max peak ?

prox arterial obstruction

what parameter @ CFA AT suggests presence of prox iliac disease

>133 msec

a greater AT or Lesser value AT is normal ?

Short AT time = normal | Long AT time = abnormal