THE RELATIVE EFFECT OF CAROTID PLAQUE HETEROGENEITY AND ECHOGENICITY ON IPSILATERAL CEREBRAL INFARCTION AND SYMPTOMS OF CEREBROVASCULAR-DISEASE

Objective. To determine the relative effect of carotid plaque heteroge neity and echogenicity as measured by computer on the incidence of ips ilateral cerebral infarction and symptoms of cerebrovascular disease. Materials and methods. 138 patients with 209 carotid plaques producing >50% stenosis were studied. 110 plaques were from symptomatic sides. All patients had computer tomography (CT) brain scans. Images of the c arotid plaques obtained by duplex scanner were transferred to a comput er. Using an image analysis program plaque echogenicity, measured as t he grey scale median (GSM) and heterogeneity, evaluated as the heterog eneity index (HI) was calculated. Results. 42% of plaques were associa ted with cerebral infarction. Symptomatic plaques and those associated with cerebral infarction were more echolucent and less heterogenous t han asymptomatic plaques and those not associated with cerebral infarc tion. Plaques with GSMs below or equal to 32 were associated with a si gnificantly higher incidence of cerebral infarction, Plaques with GSMs below or equal to 32 were associated with a significantly higher inci dence of cerebral infarction and symptoms of cerebrovascular disease t han those with GSMs above this level (p<0.01). Plaques with HIs below or equal to 20 were associated with a significantly higher incidence o f symptoms of cerebrovascular disease as compared to those with HIs ab ove this level (p<0.01). Conclusions. Computer analysis of carotid pla que morphology is an objective tool that can identify high risk plaque s. The potential of such analysis in the identification of asymptomati c patients with advanced carotid stenosis at a high risk of stroke sho uld be explored in a natural history study.