Abstract 2352: 18F-fluorodeoxyglucose PET Can Identify The Inflamed and Vulnerable Carotid Plaque - A Prospective Study in Japan

Objective - There are few studies that denote the validity of 8F-fluorodeoxyglucose (FDG) PET to detect the inflammation of severe (>70%) carotid artery stenosis in Asian populations. This study was aimed to clarify whether 18F-FDG PET can identify inflamed and vulnerable plaque at higher risk for subsequent ischemic stroke in Japanese patients with severe carotid artery stenosis. Methods - This prospective study included 33 patients with severe carotid artery stenosis between 2006 and 2011. Of these, 12 patients were symptomatic and other 21 were asymptomatic. There were 28 males and 5 females. Their mean age was 71.1 ± 8.2 years, ranging from 48 to 85. Their clinical data were precisely collected. All 33 patients underwent 18F-FDG PET and ultrasound sonography (US) to evaluate the plaque composition prior to carotid endarterectomy (CEA). FDG uptake was quantified by maximum standardized uptake values (SUV). Following surgery, the specimens were stained with the antibodies against CD68 and MMP-9. Results - High FDG uptake (SUV>2.0) was observed in 15 (45%) of 33 operated plaques. High FDG uptake significantly correlated with the other vascular disorders (P=0.048), echolucent plaque (P=0.041), lipid-rich plaque (P<0.001), CD68 expression (P<0.001), and MMP-9 expression (P=0.002). 18F-FDG PET showed significantly higher sensitivity and specificity to identify lipid-rich and CD68-positive plaque than US. However, high FDG uptake was not related to patients’ gender, age, and the degree of stenosis. There was no significant correlation between FDG uptake and symptomatic or asymptomatic patients. Conclusion - These findings strongly suggest that 18F-FDG PET would provide more valuable information to identify the inflamed, vulnerable plaque than conventional ultrasound in Japanese patients with severe carotid artery stenosis.