Doppler Principles Flashcards
1
Q
Power Doppler gives
A
amplitudes
2
Q
Power Doppler’s advantages
A
no aliasing
increased sensitivity
3
Q
Power Doppler’s diadvantages
A
range ambiguity
4
Q
5 ways to get around aliasing:
A
- increase angle of insonification (this is cheating)
- decrease depth by scanning a different axis
- decrease operating frequency (sacrificing resolution)
- increase scale size
- change position of baseline
5
Q
What is responsible for flow reversal?
A
Windkessel effect
6
Q
What two conditions can cause spectral broadening?
A
- too big a sample volume size (larger data sample)
- large variation in velocities (i.e. turbulence)
- excessive gain can look like spectral broadening - not real spectral broadening
7
Q
The ultrasound machine _____ Doppler Shift and _____ reflector velocity.
A
detects; calculates
8
Q
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
A
e) all of the above