Objectives: The aim was to determine the diagnostic value of a juxtaluminal black (hypoechoic) area without a visible echogenic cap (JBA) in ultrasonic images of internal carotid artery plaques.
Methods: Ultrasonic images of plaques from 324 patients with asymptomatic (n = 139) and symptomatic (n = 185) internal carotid 50% to 99% stenosis in relation to the bulb (European Carotid Surgery Trial) referred for duplex scanning were studied. The JBA in mm(2) and the gray-scale median (GSM) were obtained after image normalization. Cut-off points for GSM and JBA (combined highest sensitivity with highest specificity) were determined from receiver operator characteristic (ROC) curves.
Results: JBA >or= 8 mm(2) was associated with a high prevalence of symptomatic plaques in all grades of stenosis. In a multiple logistic regression model, increasing stenosis (mild, moderate, severe), GSM <or= 15 and JBA >or= 8 mm(2) were independent predictors of the presence of hemispheric symptoms. This model could identify a high-risk group of 188 plaques that contained 142 (77%) of the 185 symptomatic plaques (odds ratio [OR], 6.7; 95% confidence interval [CI], 4.08-10.91), (P < .001), (sensitivity: 77%; specificity 66%; positive predictive value 75%; negative predictive value 68%).
Conclusions: The results of this study indicate the diagnostic value and for the first time suggest a cut-off point of 8 mm(2) for JBA. This cut-off point needs to be validated in other groups and then applied to prospective studies of asymptomatic patients.
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