Multimodality Imaging of Carotid Artery Plaques 18F-Fluoro-2-Deoxyglucose Positron Emission Tomography, Computed Tomography, and Magnetic Resonance Imaging

Background and Purpose-This study's objective was to compare F-18-fluoro-2-deoxyglucose positron emission tomography (F-18-FDG PET), CT, and MRI of carotid plaque assessment. Materials and Methods-Fifty patients with symptomatic carotid atherosclerosis underwent F-18-FDG PET/CT and MRI. Correlations and agreement between imaging findings were assessed by Spearman and Pearson rank correlation tests, t tests, and Bland-Altman plots. Results-Spearman rho between plaque F-18-FDG standard uptake values and CT/MRI findings varied from -0.088 to 0.385. Maximum standard uptake value was significantly larger in plaques with intraplaque hemorrhage (1.56 vs 1.47; P = 0.032). Standard uptake values did not significantly differ between plaques with an intact and thick fibrous cap and plaques with a thin or ruptured fibrous cap on MRI. (1.21 vs 1.23; P = 0.323; and 1.45 vs 1.54; P = 0.727). Pearson rho between CT and MRI measurements varied from 0.554 to 0.794 (P < 0.001). For lipid-rich necrotic core volume, the CT-MRI correlation was stronger in mildly (<= 10%) than in severely (>10%) calcified plaques (Pearson rho 0.730 vs 0.475). Mean difference in measurement +/- 95% limits of agreement between CT and MRI for minimum lumen area, volumes of vessel wall, lipid-rich necrotic core, calcifications, and fibrous tissue were 0.4 +/- 18.1 mm(2) (P = 0.744), -41.9 +/- 761.7 mm(3) (P = 0.450), 78.4 +/- 305.0 mm(3) (P < 0.001), 180.5 +/- 625.7 mm(3) (P = 0.001), and -296.0 +/- 415.8 mm(3) (P < 0.001), respectively. Conclusions-Overall, correlations between F-18-FDG PET and CT/MRI findings are weak. Correlations between CT and MRI measurements are moderate to strong, but there is considerable variation in absolute differences. (Stroke. 2009; 40: 3718-3724.)