Extracranial carotid vascular disease: detection by real time B-mode ultrasonography.

Real time B-mode ultrasonography is a currently popular technique used to screen patients with suspected carotid vascular disease and identify those who need cerebral angiography. From September 1981 through February 1983, 1,205 patients had carotid ultrasonography in the Vascular Laboratory at Erlanger Medical Center. Retrospective review of these patients identified 260 who also had cerebral angiography. In these 260 patients, 517 arteries were studied with ultrasound and then compared to angiographic results, using the angiograms as control. In this study, there was a technical success rate of 89% for all ultrasonic procedures done. With positive disease considered as stenosis of more than 40%, the overall accuracy was 79%, sensitivity was 81%, and specificity was 77%. The false-positive rate was 14% and the false-negative rate 7%. Carotid ultrasonography accurately detected total vessel occlusion in 91% of such cases. Ultrasonic studies were not consistently accurate in the detection of ulcerative plaques where compared to angiographic results.