
Q9 Digital Color Doppler Ultrasound System
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Fig. 4-9 CFM Mode
CFM Scanning Hints:
PRF: increase/decrease the PRF on the color bar. Imaging of higher velocity flow requires increased velocity scale
values to avoid aliasing
Wall Filter: affect low flow sensitivity versus motion artifact
Color Map: allow you to select a specific color map.
It shows the direction of the flow and highlights the higher
velocity flows.
Color Gain: amplify the overall strength of echoes processed in the CROI
Persistence: affect temporal smoothing and color Doppler ‘robustness’.
Line Density: trade frame rate for sensitivity and spatial resolution. If the frame rate is too slow, decrease the CROI
size and the line density.
4.3.10.
PD (CPA) Mode
Power Doppler Imaging (PD) is a color flow mapping technique used to map the strength of the Doppler signal
coming from the flow rather than the frequency shift of the signal. Using this technique, the ultrasound system
plots color flow based on the number of reflectors that are moving, regardless of their velocity. PD does not map
velocity, therefore it is not subject to aliasing.