Comparison of pulsed Doppler and real-time B-mode echo arteriography for noninvasive imaging of the extracranial carotid arteries.

Accuracy and clinical applications of noninvasive imaging of the extracranial carotid arteries were compared using pulsed Doppler and real-time B-mode ultrasonography. During the period December, 1977, to February, 1979, 530 ultrasonograms (265 patients) were performed. Angiographic correlations were available in 90 patients (172 arteries) using the pulsed Doppler technique, and both techniques were employed in 43 patients (84 arteries). Greatest accuracy with pulsed Doppler ultrasonography occurred in confirmation of normal vasculature (73%) and diagnosis of occluded internal carotid arteries (96%). Estimation of the percentage of stenosis was less accurate; however, this determination could be made somewhat more accurately by B-mode ultrasonography. Incidence of false positive and negative results for the pulsed Doppler technique was 11% and 14%, respectively, whereas for the corresponding incidence for B-mode imaging it was 11% and 59%. The higher incidence of false negative results with the B-mode technique related to its inaccuracy in diagnosis of occlusion (18%). Current clinical applications of carotid ultrasonography include confirmation of normalcy and diagnosis of occlusion, visualization of atheroslerotic plaques with characterization of their size and ultrasonic morphology, and an anticipated reduction in the requirements for contrast arteriography in selected patients.