Carotid Plaque Inflammation Imaged by ¹⁸F-Fluorodeoxyglucose Positron Emission Tomography and Risk of Early Recurrent Stroke

Background and Purpose-Plaque inflammation contributes to stroke and coronary events. ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET) identifies plaque inflammation-related metabolism. Almost no prospective data exist on the relationship of carotid ¹⁸F-FDG uptake and early recurrent stroke. Methods-We did a multicenter prospective cohort study BIOVASC (Biomarkers/Imaging Vulnerable Atherosclerosis in Symptomatic Carotid disease) of patients with carotid stenosis and recent stroke/transient ischemic attack with 90-day follow-up. On coregistered carotid ¹⁸F-FDG PET/computed tomography angiography, ¹⁸F-FDG uptake was expressed as maximum standardized uptake value (SUV_max) in the axial single hottest slice. We then conducted a systematic review of similar studies and pooled unpublished individual-patient data with 2 highly similar independent studies (Dublin and Barcelona). We analyzed the association of SUV_max with all recurrent nonprocedural stroke (before and after PET) and with recurrent stroke after PET only. Results-In BIOVASC (n=109, 14 recurrent strokes), after adjustment (for age, sex, stenosis severity, antiplatelets, statins, diabetes mellitus, hypertension, and smoking), the hazard ratio for recurrent stroke per 1 g/mL SUV_max was 2.2 (CI, 1.1-4.5; P=0.025). Findings were consistent in the independent Dublin (n=52, hazard ratio, 2.2; CI, 1.1-4.3) and Barcelona studies (n=35, hazard ratio, 2.8; CI, 0.98-5.5). In the pooled cohort (n=196), 37 recurrent strokes occurred (29 before and 8 after PET). Plaque SUV_max was higher in patients with all recurrence (P<0.0001) and post-PET recurrence (P=0.009). The fully adjusted hazard ratio of any recurrent stroke was 2.19 (CI, 1.41-3.39; P<0.001) and for post-PET recurrent stroke was 4.57 (CI, 1.5-13.96; P=0.008). Recurrent stroke risk increased across SUV_max quartiles (log-rank P=0.003). The area under receiver operating curve for all recurrence was 0.70 (CI, 0.59-0.78) and for post-PET recurrence was 0.80 (CI, 0.64-0.96). Conclusions-Plaque inflammation-related ¹⁸F-FDG uptake independently predicted future recurrent stroke post-PET. Although further studies are needed, ¹⁸F-FDG PET may improve patient selection for carotid revascularization and suggest that anti-inflammatory agents may have benefit for poststroke vascular prevention.