Ultrasonic doppler spectral broadening in the diagnosis of internal carotid artery stenosis.

In a clinical study, 78 carotid bifurcations were examined by pulsed Doppler ultrasonography and X-ray arteriography. Maximum Doppler frequencies greater than or equal to 3 kHz diagnosed stenoses of greater than or equal to 25% diameter reduction with a sensitivity of 73% and specificity of 79%. A quantitative analysis of the degree of spectral broadening was obtained from the ratio of the maximum to mean frequency at peak systole and improved the sensitivity and specificity to 90% and 98% respectively. All vessels greater than 40% stenosis were correctly classified as stenosed and all less than 20% stenosis were classified as normal.