Doppler Principles

Question 1

Power Doppler gives

Answer 1

amplitudes

Question 2

Power Doppler’s advantages

Answer 2

no aliasing
increased sensitivity

Question 3

Power Doppler’s diadvantages

Answer 3

range ambiguity

Question 4

5 ways to get around aliasing:

Answer 4

1. increase angle of insonification (this is cheating)
2. decrease depth by scanning a different axis
3. decrease operating frequency (sacrificing resolution)
4. increase scale size
5. change position of baseline

Question 5

What is responsible for flow reversal?

Answer 5

Windkessel effect

Question 6

What two conditions can cause spectral broadening?

Answer 6

1. too big a sample volume size (larger data sample)
2. large variation in velocities (i.e. turbulence)
3. excessive gain can look like spectral broadening - not real spectral broadening

Question 7

The ultrasound machine _____ Doppler Shift and _____ reflector velocity.

Answer 7

detects; calculates

Question 8

Which factors affect the quality of the spectral window in a spectral tracing?
a) overall gain
b) quality of blood flow (not controllable by the sonographer)
c) whether pulsed wave or continuous wave is used
d) position of the SV box
e) all of the above

Answer 8

e) all of the above