Computer analysis of ultrasonic plaque echolucency in identifying high risk carotid bifurcation lesions

Objectives: to confirm that plaque echogenicity evaluated by computer analy sis, as suggested by preliminary studies, can identify plaques associated w ith a high incidence of strokes. Materials and methods: a series of 96 patients with carotid stenosis in the range of 50-99% were studied retrospectively (41 with TIAs and 55 asymptom atic). Carotid plaque echogenicity teas evaluated using a computerised meas urement of the median grey scale value (GSM). AII patients had a CT brain s can to determine the presence of infarction in the carotid territory. Results: the incidence of ipsilateral brain CT infarctions was 16% in the a symptomatic and 32% in the symptomatic plaques (p = 0.076). It was 20% for <70% stenosis and 25% for >70% stenosis (p = 0.52). It was 9% for plaques w hich had a GSM >50 and 40% in those with GSM <50 (p<0.001) with a relative risk of 4.6 (95% CI 1.8 to 11.6). Conclusions: the results confirm that computer analysis of plaque echogenic ity is better than the degree of stenosis in identifying plaques associated with an increased incidence of CT brain-scan infarction and consequently u seful for identifying individuals at high risk of stroke. What is required is a form of image standardisation in order to apply this method to natural history studies with stroke as the endpoint.