Under Washington's ICA stenosis criteria, PSV>125 cm/s and EDV>140 cm/s with spectral broadening correspond to what percent diameter reduction?

• A. 60-79%
• B. 80-99%
• C. >95%
• D. 100% occlusion

Answer: (B)

The key idea is how duplex Doppler velocity patterns map to the amount of narrowing in the internal carotid artery using Washington criteria. When the waveform shows very high forward velocities and turbulence, you’re seeing a high-grade stenosis. Specifically, a peak systolic velocity greater than about 125 cm/s and an end-diastolic velocity greater than about 140 cm/s, with spectral broadening, aligns with severe narrowing in the 80–99% range. The high velocities occur because the narrow lumen accelerates flow, and spectral broadening reflects turbulent flow from that tight aperture. This pattern points to substantial stenosis, not complete occlusion. If the artery were completely occluded, you’d expect little to no flow signal in the ICA and possible collateral flow, rather than high-velocity, broadened spectra. Lower ranges of stenosis (moderate to mild) produce lower velocities and less spectral broadening, so they don’t fit these velocity thresholds.