Which imaging mode provides velocity and direction information?

• A. B-mode
• B. Color Doppler
• C. Power Doppler
• D. Spectral Doppler

Answer: (B)

Velocity and direction information come from Doppler shift measurements, and Color Doppler translates those shifts into a real-time color map over the image. By encoding toward or away from the transducer with different colors and varying the shade to reflect speed, it shows both how fast flow is and which way it’s moving at many points simultaneously, overlaid on the anatomical image.

B-mode only shows anatomy in grayscale, with no flow data. Power Doppler detects the presence and strength of flow but not its speed or direction. Spectral Doppler does provide velocity and direction, but along a single line over time (a waveform), not across the whole image like Color Doppler.