[The value of (18)F-fluorodeoxyglucose positron emission tomography-computed tomography ((18)F-FDG PET-CT) in evaluating the stability of atherosclerotic plaques]

Objective: Positron emission tomography-computed tomography (PET-CT) has been used to quantify inflammatory response in the body. The aim of the present study was to explore the possibility of using this method to evaluate the stability of atherosclerotic plaques and the efficacy of atorvastatin in stabilizing atherosclerotic plaques. Methods: Twenty New Zealand male white rabbits were included and divided into the atorvastatin intervention group and the control group, with 10 rabbits in each group. Rabbits in both groups were fed with a high fat diet for 20 weeks, and treated with thoracoabdominal aortic balloon-pulling to establish atherosclerosis model at the end of the 2nd week. Rabbits in atorvastatin intervention group was given atorvastatin intragastrically once a day. At the 8th week, thoracoabdominal aortic ultrasound was used to detect plaques in all rabbits. Blood was drawn at the 3rd and the 20th week, respectively, to measure blood lipids, high-sensitive C-reactive protein (hs-CRP) and matrix metalloproteinase-9 (MMP-9). At the end of experiment, survival animals were scanned by (18)F-FDG PET-CT, and the average and maximum standard uptake values (SUVmean, SUVmax) of aortic segments were measured. Thereafter, the animals were sacrificed and aortic specimens of rabbits were taken and examined by immunohistochemistry. The pathological indexes were measured and compared. Results: At the end of experiment, the total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), hs-CRP [ (4.58±0.51) ng/ml vs.(5.87±0.66) ng/ml, P<0.01], MMP-9[ (43.93±2.16) ng/ml vs. (50.77±2.32) ng/ml, P<0.01], SUVmean (0.59±0.15 vs. 0.68±0.20, P<0.05) , SUVmax (0.68±0.20 vs. 0.81±0.27, P<0.05) , plaque area [ (0.36±0.24) mm(2) vs. (0.50±0.34) mm(2), P<0.05) ] and density of macrophage[ (4.34±1.54) % vs. (5.65±1.89) %, P<0.01] in the atorvastatin intervention group were significantly lower than those in the control group. In contrast, fiber cap thickness of the plaque[ (4.12±0.66) μm vs. (2.96±0.37) μm, P<0.01] in the atorvastatin intervention group was higher than that of the control group, and the difference was statistically significant. The arterial plaque areas were positively correlated with SUVmean (r=0.27, P<0.05) and SUVmax (r=0.43, P<0.01) . Fiber cap thickness was negatively correlated with SUVmean (r=-0.38, P<0.05) and SUVmax (r=-0.47, P<0.01) . The density of macrophage were positively correlated with SUVmean (r=0.52, P<0.01) and SUVmax (r=0.51, P<0.01) . Conclusion: (18)F-FDG PET/CT can be used to evaluate the efficacy of atorvastatin by the stability of atherosclerotic plaques.