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Ultrasound Vascular Technology > Doppler Waveform Analysis > Flashcards

Doppler Waveform Analysis Flashcards

1
Q

Capabilities of doppler waveform analysis?

A
  • help confirm diagnosis / approximate location of arterial occlusive disease
  • Indicate severity
  • Combine with doppler segmental pressures
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2
Q

Limitations of doppler waveform analysis?

A
  • casts/bandages
  • waveforms may be affected by ambient temperature
  • Uncompensated congestive heart failure may result in dampened waveforms ***
  • Unable to discriminate stenosis from occlusion
  • tech dependent
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3
Q

Why do you do doppler waveforms with patient supine?

A

to decrease influence of hydrostatic pressure

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4
Q

Positioning for doppler waveform:

A
  • supine
  • hip rotated / knee slightly bent
  • RLD/LLD
  • prone
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5
Q

What is the doppler effect?

A

When a wave is reflected from a moving target, the frequency of the wave received is different (doppler shift) from the transmitted wave

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6
Q

Why does the doppler effect occur?

A

Relative to motion between the source and the receiver of the sound

(blood is moving target; transducer is stationary source)

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7
Q

What many crystals does continuous wave (CW) have?

A

two

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8
Q

The reflected frequency is higher/lower than the transmitted frequency depending on what?

A

direction of flow

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9
Q

What does an analog reader do?

A

employs a zero crossing frequency meter, to display the signals graphically on a strip chart recorder

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10
Q

Paper speed of an analog reader is:

A

25mm/sec

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11
Q

What does a zero crossing frequency meter count?

A

Each time the input signal crosses though zero (the baseline) within a time span

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12
Q

With zero crossing frequency meter, high frequency waves have how many oscillations?

A

many

lower frequencies have fewer

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13
Q

What does a zero crossing frequency meter machine estimate?

A

Frequencies present in reflected signal and displays them

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14
Q

Drawbacks of Analog:

A
  • Noise
  • Less sensitivity
  • High velocities are underestimated
  • Low velocities are oversestimated
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15
Q

What does spectral analysis display?

A

Individual frequencies displayed by Fast Fourier Transform (FFT) method

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16
Q

How is spectral analysis displayed? (x/y)

A

(X) Horizontal - displays time
(Y) Vertical - displays frequency shifts

17
Q

What analysis is more commonly used during duplex evaluations?

A

Spectral

18
Q

What probe is utilized for CW doppler?

A

8-10 MHz doppler probe

19
Q

Upper extremity arteries are recorded from the following (top to bottom) bilaterally:

A
  • Subclavian
  • Axillary
  • Brachial (at elbow)
  • Radial (thumb side, at wrist)
  • Ulnar (5th finger side, at wrist)
20
Q

Lower extremity arteries are recorded from the following (top to bottom) bilaterally:

A
  • Common femoral (CFA)
  • Superficial femoral (SFA)
  • Popliteal
  • Posterior tibial (PTA) (medial malleolus)
  • Dorsalis pedis (DPA) (top of foot)
  • Peroneal (if necessary) (lateral malleolus)
21
Q

The audible AND wave form qualities are observed, documented, and combined with what?

A

Doppler segmental pressures

22
Q

What waveform has a rapid upslope, sharp peak, rapid down-stroke, flow reversal, and resumption of forward flow?

A

Triphasic

23
Q

What are examples of triphasic flow?

A

UE, LE, arteries

24
Q

What waveform has a rapid upslope, sharp peak, fairly rapid downstroke, flow reversal, no resumption of forward flow and can be considered normal in some patients?

A

Biphasic

25
Q

What waveform has a slow upslope, rounded peak, slow down-stroke, and no reversal?

A

Monophasic

26
Q

The dicrotic notch is also known as what?

A

Reflected wave

27
Q

A monophasic/dampened (pulsatile) signal is often obtained where?

A

proximal to an obstruction

28
Q

Well collateralized occlusions can appear similar to flow distal to what?

A

a stenosis

29
Q

Vasoldilation of the distal vessels often occur with

A

Proximal obstruction

30
Q

What will happen with a proximal occlusion or critical stenosis of the subclavian artery?

A

Will make the signal more monophasic

31
Q

Strandness and Subner describe what?

A

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

32
Q

What is a normal doppler wave-form post exercise?

A

Pre-exercise wave form qualities are maintained and/ or augmented

33
Q

What is an abnormal doppler wave-form post exercise?

A

Slow upstroke with more rounded peak, slow downstroke, no reverse component

34
Q

Analog Doppler not capable of portraying velocities of less than:

A

6 cm/sec

35
Q

How do you troubleshoot the machine if it says “60 cycle” noise on tracing?

A

Decrease gain; turn system off/on; increase filter; try another plug receptable.

36
Q

How is the pulsatility Index (PI) calculated?

A

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

37
Q

An acceleration time of >133msec suggests what?

A

presence of proximal iliac disease

Ultrasound Vascular Technology (12 decks)

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