Carotid atherosclerosis: high-resolution real-time sonography correlated with angiography

The merits of high-resolution real-time sonography in detection of plaque and estimation of stenoses were compared with angiography in 97 carotid bifurcations from 50 consecutive patients. For flow-reducing lesions, that is, stenosis greater than or equal to 50% or complete occlusion, sonographic accuracy was 86% and the mean difference in percentage narrowing was 17% (SD, 21.6%). For detection of normal or non-flow-reducing lesions, that is, less than 50% stenosis, sonographic accuracy was 89% and the mean difference in percentage narrowing was 8% (SD, 10.2%). Errors occurred mainly in severely diseased vessels and were often related to calcification in lesions and/or plaque of low echogenicity. Accuracy was lowest in predicting complete vessel occlusion (36%). Greatest accuracy was found in assessment of minimal disease. The technique is a useful supplement to the battery of noninvasive tests used to screen patients at risk for stroke and in defining those requiring angiography before surgery.