Which statement correctly describes color Doppler's displayed velocity information?

Which statement correctly describes color Doppler's displayed velocity information?

• A. It displays average velocity values, not peak velocity values
• B. It displays peak velocity values, not average
• C. It displays both peak and average velocity values
• D. It displays neither velocity value

Answer: (A)

Color Doppler conveys the mean flow velocity within the imaging voxel along the ultrasound beam. The system estimates velocity over time using autocorrelation, producing a single representative velocity for each color pixel—the average—not the instantaneous peak. That’s why the color map shows flow direction and relative speed as a stable pattern rather than sharp spikes. If you need exact peak velocities, you’d use spectral Doppler, which provides waveforms with peak values. The color map uses hue for direction (toward or away) and brightness to reflect the mean velocity magnitude. In short, color Doppler displays average velocity within the gate, not peak velocity.

Color Doppler conveys the mean flow velocity within the imaging voxel along the ultrasound beam. The system estimates velocity over time using autocorrelation, producing a single representative velocity for each color pixel—the average—not the instantaneous peak. That’s why the color map shows flow direction and relative speed as a stable pattern rather than sharp spikes. If you need exact peak velocities, you’d use spectral Doppler, which provides waveforms with peak values. The color map uses hue for direction (toward or away) and brightness to reflect the mean velocity magnitude. In short, color Doppler displays average velocity within the gate, not peak velocity.