Abstract WP72: Recurrent Cerebral Ischemic Events in Symptomatic Carotid Stenosis are Related to Plaque Inflammation

Abstract

Background and Aims: Severity of symptomatic carotid stenosis often determines the treatment approach. However, severity explains only the regional hypoperfusion as the mechanism of cerebral ischemia. Artery-to-artery embolisation remains an important pathogenic mechanism in patients with high-risk carotid plaques. Inflammation is considered as the initiating event for plaque rupture and cerebral embolism. Using 18F-fluorodeoxyglucose positron-emission tomography (FDG-PET)/computed tomography (CT) and high-resolution magnetic resonance imaging (HR-MRI), we investigated the role of plaque imaging in stroke recurrence in our patients with recently symptomatic carotid stenosis. Methods: This prospective study included consecutive patients within 30-days of recent stroke and ipsilateral carotid stenosis (≥50%). FDG uptake was quantified as mean standardized uptake values (SUV, g/ml). The ratio of T1 hyperintensity of carotid plaque to the ipsilateral sternocleidomastoid muscle (SCM) was recorded on T1-weighted fat suppressed HR-MRI. Patients were followed-up for stroke recurrence within 90-days. Results: Of the 115 patients included in the study, 17 (15%) suffered from recurrent cerebral ischemic event in the stenosed carotid territory within 90-days. Compared to patients who remained asymptomatic, patients with recurrent cerebral ischemia showed higher mean T1 carotid-SCM ratio (2.19 versus 1.38; p<0.0001) and higher mean SUV value in the carotid plaque (3.04g/ml versus 1.25g/ml; p<0.0001). Higher T1 carotid-SCM ratio on HR-MRI (OR 3.215, 95%CI 1.304-5.927; p<0.0001) and higher mean SUV on FDG-PET (OR 3.601, 95%CI 2.924-7.628; p=0.005) were independent predictors of recurrent cerebral ischemia. Conclusions: FDG-PET/CT and HR-MRI of carotid stenosis are useful tools for risk stratification and may aid in better therapeutic decision-making.