Which velocity metric is most commonly reported as the primary measure of arterial flow?

• A. Peak systolic velocity
• B. End-diastolic velocity
• C. Time-averaged velocity
• D. Mean velocity

Answer: (A)

Peak systolic velocity is the main metric because it captures the highest blood speed during the heartbeat, where the flow jet through a narrowed segment is most pronounced. When an artery narrows, the same volume of blood must pass through a smaller area, so velocity rises during systole. This makes peak systolic velocity a sensitive and reproducible indicator of stenosis severity and a standard reference in duplex Doppler studies. End-diastolic velocity can vary with downstream resistance and heart rate, so it’s less reliable for grading narrowing. Time-averaged or mean velocity smooths the waveform and can mask the peak jet, reducing sensitivity to focal narrowing. Therefore, peak systolic velocity is the most commonly reported primary measure of arterial flow.