In vivo 18F-fluorodeoxyglucose positron emission tomography imaging provides a noninvasive measure of carotid plaque inflammation in patients
Ahmed Tawakol, Raymond Q Migrino, Gregory G Bashian, Shahinaz Bedri, David Vermylen, Ricardo C Cury, Denise Yates, Glenn M LaMuraglia, Karen Furie, Stuart Houser, Henry Gewirtz, James E Muller, Thomas J Brady, Alan J Fischman, Ahmed Tawakol, Raymond Q Migrino, Gregory G Bashian, Shahinaz Bedri, David Vermylen, Ricardo C Cury, Denise Yates, Glenn M LaMuraglia, Karen Furie, Stuart Houser, Henry Gewirtz, James E Muller, Thomas J Brady, Alan J Fischman
Abstract
Objectives: Given the importance of inflammation in atherosclerosis, we sought to determine if atherosclerotic plaque inflammation could be measured noninvasively in humans using positron emission tomography (PET).
Background: Earlier PET studies using fluorodeoxyglucose (FDG) demonstrated increased FDG uptake in atherosclerotic plaques. Here we tested the ability of FDG-PET to measure carotid plaque inflammation in patients who subsequently underwent carotid endarterectomy (CEA).
Methods: Seventeen patients with severe carotid stenoses underwent FDG-PET imaging 3 h after FDG administration (13 to 25 mCi), after which carotid plaque FDG uptake was determined as the ratio of plaque to blood activity (target to background ratio, TBR). Less than 1 month after imaging, subjects underwent CEA, after which carotid specimens were processed to identify macrophages (staining with anti-CD68 antibodies).
Results: There was a significant correlation between the PET signal from the carotid plaques and the macrophage staining from the corresponding histologic sections (r = 0.70; p < 0.0001). When mean FDG uptake (mean TBR) was compared with mean inflammation (mean percentage CD68 staining) for each of the 17 patients, the correlation was even stronger (r = 0.85; p < 0.0001). Fluorodeoxyglucose uptake did not correlate with plaque area, plaque thickness, or area of smooth muscle cell staining.
Conclusions: We established that FDG-PET imaging can be used to assess the severity of inflammation in carotid plaques in patients. If subsequent natural history studies link increased FDG-PET activity in carotid arteries with clinical events, this noninvasive measure could be used to identify a subset of patients with carotid atherosclerosis in need of intensified medical therapy or carotid artery intervention to prevent stroke.
Source: PubMed