What is an advantage of using high-PRF Doppler?

• A. Higher frame rate
• B. Ability to measure high velocities
• C. Improved range resolution
• D. Greater sensitivity to slow flow

Answer: (B)

High PRF raises the rate at which Doppler samples are taken, which pushes up the maximum velocity you can measure without aliasing. In pulsed Doppler, the Doppler shift you can accurately interpret is limited by the Nyquist limit, which is tied to PRF. When flow is fast, a low PRF can cause the measured velocity to wrap around and appear misleadingly low or in the wrong direction. By using a higher PRF, that aliasing threshold increases, allowing true high velocities to be reported correctly.

This is the primary advantage of high-PRF Doppler: it enables measurement of higher velocities. Other effects of PRF, like frame rate or range resolution, are not the main reason this setting is chosen for fast flows, and sensitivity to very slow flow isn’t the focus of this benefit.