Correlation of duplex scanning and two plane angiography in patients with symptomatic carotid stenosis.

The correlation between flow velocity and percent stenosis in carotid arteries was assessed in 43 symptomatic patients (86 carotids) using duplex scanning and angiography. Duplex scanning evaluation was performed using the ATL Ultramark 4 duplex scanner with the 5-7.5-10 MHz probe. Using the ratio of peak velocity in the internal carotid in systole (VICA) to the end diastolic velocity in the common carotid (VCCA) we studied its correlation with the percent stenosis observed by angiography. A good correlation (r = .95) was found. The graph obtained indicates that a significant (greater than 50%) stenosis may be graded by the VICA/VCCA ratio with a high degree of accuracy (97%). This may be useful not only for screening patients to select for angiography and surgery but also to follow up the natural history of carotid stenosis.