B-mode Ultrasound Imaging in Symptomatic Internal Carotid Artery Stenosis: Correlation with Clinical and Operative Findings

Abstract

B-mode ultrasound (duplex) imaging is a technique that enables the evaluation of plaque characteristics. The purpose of this study was to determine the accuracy and usefulness of duplex imaging by comparing a relationship between the preoperative clinical neurologic status, preoperative duplex findings, and operative findings in patients who had carotid endarterectomy (CEA) for symptomatic high-grade internal carotid artery (ICA) stenosis. Sixty patients with symptomatic ICA stenosis who underwent CEA from September 1995 to August 1998 were included in this study. Plaque morphology was categorized in terms of echogenicity by preoperative duplex imaging. A correlation between the frequency of preoperative ischemic stroke and duplex and operative findings was prospectively evaluated. Thirty-eight patients had recent and multiple cerebral ischemia, and 22 experienced a single episode more than 1 month before CEA. Recent and multiple events occurred in 24 (72.7%) of 33 patients with echolucent plaques, but only 6 (40.0%) of 15 with echogenic plaques (p<0.05). Thirty-six (75%) of 48 patients with soft plaques by operative findings had recent and multiple events, but only two (16.7%) of 12 with calcified plaques experienced recent and multiple events (p<0.01). Overall sensitivity, specificity, and accuracy of duplex imaging were 79.5%, 77.8%, and 79.2%, respectively. Duplex imaging is reliable in determining ICA plaque characteristics. Recent and multiple cerebral ischemia occurred more frequently in patients with echolucent plaques by preoperative duplex and soft plaques by operative findings. The presence of echolucent plaque may be used as a strong indication for CEA in patients who have asymptomatic high-grade ICA stenosis.