Which imaging mode is specifically designed to measure blood flow velocity using Doppler shifts?

• A. A-Mode
• B. B-Mode
• C. Pulsed-Wave Doppler
• D. M-Mode

Answer: (C)

Measuring blood flow velocity with Doppler shifts relies on detecting the change in frequency of the sound wave as it reflects off moving blood cells. Pulsed-Wave Doppler uses short ultrasound pulses and samples echoes from a specific depth along the beam, so you can place a defined sample volume in a vessel and compute velocity from the Doppler frequency shift. The display shows a spectral trace of velocity over time and indicates direction toward or away from the transducer. This targeted velocity measurement at a location distinguishes it from A-Mode (amplitude vs depth), B-Mode (2D grayscale anatomy), and M-Mode (motion along a line over time without Doppler velocity information). Therefore, this mode is designed to measure blood flow velocity using Doppler shifts.