High-Intensity Signal on Time-of-Flight Magnetic Resonance Angiography Indicates Carotid Plaques at High Risk for Cerebral Embolism During Stenting

Background and Purpose-A major disadvantage of carotid artery stenting (CAS) compared to carotid endarterectomy is the increased risk of cerebral embolism. Thus, establishing a simple method to discriminate fragile plaques on preoperative routine examination is important. The present study examined whether high-intensity signal (HIS) in the plaque on time-of-flight (TOF) MRA, performed for screening, can discriminate plaque at high risk for cerebral embolism during CAS. Methods-In the 30 patients treated using carotid endarterectomy, relationships between pathological findings of the plaques and TOF-MRA findings were analyzed. In the 112 patients treated using CAS, postoperative ipsilateral ischemic lesions on diffusion-weighted imaging and periprocedural ischemic symptoms were analyzed. Results-The percentage area of intraplaque hemorrhage stained by glycophorin A was significantly larger in HIS-positive plaques (51.8%+/- 9.8%) than in HIS-negative plaques (8.6%+/- 9.4%; P<0.001). Postoperative ischemic lesions on diffusion-weighted imaging were more frequent in the HIS-positive plaques (25/38; 65.8%) than in the HIS-negative plaques (26/74; 35.1%; P=0.002). Periprocedural ischemic symptoms were more frequently observed in HIS-positive plaques (7/38; 18.4%) than in HIS-negative plaques (1/74; 1.4%; P=0.003). Multivariate logistic regression analysis identified HIS on TOF-MRA as an independent predictor of periprocedural ischemic symptoms (odds ratio, 15.08; 95% confidence interval, 1.76-129.0). Conclusions-HIS in the plaque on TOF-MRA performed for screening could discriminate plaques at high risk for cerebral embolism during CAS. (Stroke. 2011;42:3132-3137.)