01.04.2014 | Original Article
18F-FDG PET and intravascular ultrasonography (IVUS) images compared with histology of atherosclerotic plaques: 18F-FDG accumulates in foamy macrophages
Erschienen in: European Journal of Nuclear Medicine and Molecular Imaging | Ausgabe 4/2014
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Purpose
Intravascular ultrasonography (IVUS) and 18F-FDG PET have been used to evaluate the efficacy of antiatherosclerosis drugs. These two modalities image different characteristics of atherosclerotic plaques, and a comparison of IVUS and PET images with histology has not been performed. The aim of this study was to align IVUS and PET images using anatomic landmarks in Watanabe heritable hyperlipidaemic (WHHL) rabbits, enabling comparison of their depiction of aortic atherosclerosis. Cellular 18F-FDG localization was evaluated by 3H-FDG microautoradiography (micro-ARG).
Methods
A total of 19 WHHL rabbits (7 months of age) were divided into three groups: baseline (n = 6), 3 months (n = 4), and 6 months (n = 9). PET, IVUS and histological images of the same aortic segments were analysed. Infiltration by foamy macrophages was scored from 0 to IV using haematoxylin and eosin (H&E) and antimacrophage immunohistochemical staining, and compared with 3H-FDG micro-ARG findings in two additional WHHL rabbits.
Results
IVUS images did not identify foamy macrophage deposition but revealed the area of intimal lesions (r = 0.87). 18F-FDG PET revealed foamy macrophage distribution in the plaques. The intensity of 18F-FDG uptake was correlated positively with the degree of foamy macrophage infiltration. Micro-ARG showed identical 3H-FDG accumulation in the foamy macrophages surrounding the lipid core of the plaques.
Conclusion
F-FDG PET localized and quantified the degree of infiltration of foamy macrophages in atherosclerotic lesions. IVUS defined the size of lesions. 18F-FDG PET is a promising imaging technique for evaluating atherosclerosis and for monitoring changes in the composition of atherosclerotic plaques affecting their stability.
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