Background — Atherosclerotic plaque rupture is usually a consequence of inflammatory cell activity within the plaque. Current imaging techniques provide anatomic data but no indication of plaque inflammation. The glucose analogue [ 18 F]-fluorodeoxyglucose ( 18 FDG) can be used to image inflammatory cell activity non-invasively by PET. In this study we tested whether 18 FDG-PET imaging can identify inflammation within carotid artery atherosclerotic plaques. Methods and Results — Eight patients with symptomatic carotid atherosclerosis were imaged using 18 FDG-PET and co-registered CT. Symptomatic carotid plaques were visible in 18 FDG-PET images acquired 3 hours post- 18 FDG injection. The estimated net 18 FDG accumulation rate (plaque/integral plasma) in symptomatic lesions was 27% higher than in contralateral asymptomatic lesions. There was no measurable 18 FDG uptake into normal carotid arteries. Autoradiography of excised plaques confirmed accumulation of deoxyglucose in macrophage-rich areas of the plaque. Conclusions — This study demonstrates that atherosclerotic plaque inflammation can be imaged with 18 FDG-PET, and that symptomatic, unstable plaques accumulate more 18 FDG than asymptomatic lesions.

Imaging Atherosclerotic Plaque Inflammation With [ 18 F]-Fluorodeoxyglucose Positron Emission Tomography