Use of diastolic velocity ratios to predict significant carotid artery stenosis.

Duplex scanning of the carotid bifurcation has emerged as an accurate noninvasive means of predicting and quantifying carotid arterial stenoses. Compared with the more widely reported measurements of spectral broadening and peak frequency ratios, measurements of diastolic velocity ratios have theoretical advantages in predicting carotid artery stenosis. The use of diastolic velocity ratios between the internal and common carotid arteries was prospectively studied in 30 consecutive patients to determine its accuracy in predicting significant stenosis of the internal carotid artery when compared with angiography. A total of 55 carotid bifurcations were studied, and the use of diastolic velocity ratios correctly predicted high-grade stenosis (greater than or equal to 75% diameter reduction) in 52 cases (95%). We conclude that diastolic velocity ratios may be used to accurately detect significant internal carotid artery stenosis.