Which post-injection PSV value range is considered marginal?

• A. 10-24 cm/s
• B. 40-50 cm/s
• C. 30-39 cm/s
• D. 25-29 cm/s

Answer: (D)

In duplex Doppler, interpretation hinges on where the peak systolic velocity sits relative to established reference ranges for the vessel and context. Post-injection velocities reflect the immediate perfusion state after enhancement, so there are zones that are clearly high, clearly low, and a middle zone that’s not clearly normal or abnormal.

A post-injection PSV of 25–29 cm/s sits in that middle, borderline region. It’s not as low as velocities that would suggest markedly reduced flow or high resistance, and it isn’t as high as values typically seen with overt flow acceleration from significant stenosis or hyperemia. Hence it’s considered marginal: velocity is neither clearly normal nor clearly abnormal, so you should correlate with other findings such as end-diastolic velocity, resistive index, waveform contour, symmetry with the opposite side, and the patient’s clinical status, and possibly repeat the study or use additional imaging if needed.

The other ranges are interpreted with broader implications: lower values indicate reduced flow, higher values raise concern for abnormal flow states, and the more elevated end of the spectrum would typically prompt closer scrutiny for potential pathology.