Partial volume effect-corrected FDG PET and grey matter volume loss in patients with mild Alzheimer’s disease
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Although 18F-fluorodeoxyglucose (FDG) PET is an established imaging technique to assess brain glucose utilisation, accurate measurement of tracer concentration is confounded by the presence of partial volume effect (PVE) due to the limited spatial resolution of PET, which is particularly true in atrophic brains such as those encountered in patients with Alzheimer’s disease (AD). Our aim was to investigate the effects of PVE correction on FDG PET in conjunction with voxel-based morphometry (VBM) in patients with mild AD.
Thirty-nine AD patients and 73 controls underwent FDG PET and MRI. The PVE-corrected grey matter PET images were obtained using an MRI-based three-compartment method. Additionally, the results of PET were compared with grey matter loss detected by VBM.
Before PVE correction, reduced FDG uptake was observed in posterior cingulate gyri (PCG) and parieto-temporal lobes (PTL) in AD patients, which persisted after PVE correction. Notably, PVE correction revealed relatively preserved FDG uptake in hippocampal areas, despite the grey matter loss in medial temporal lobe (MTL) revealed by VBM.
FDG uptake in PCG and PTL is reduced in AD regardless of whether or not PVE correction is applied, supporting the notion that the reduced FDG uptake in these areas is not the result of atrophy. Furthermore, FDG uptake by grey matter tissue in the MTL, including hippocampal areas, is relatively preserved, suggesting that compensatory mechanisms may play a role in patients with mild AD.
KeywordsAlzheimer’s disease FDG PVE Cortical atrophy Hippocampus
This study was supported in part by a grant for Development of Advanced Technology for Measurement and Evaluation of Brain Functions, Ishikawa Prefecture Collaboration of Regional Entities for the Advancement of Technological Excellence (to S.N. and M.Y.), from Japan Science and Technology Corporation, Japan, and by a grant for the Knowledge Cluster Initiative [High-Tech Sensing and Knowledge Handling Technology (Brain Technology)] (to M.Y.) from the Japanese Ministry of Education, Culture, Sports, Science and Technology, Japan. The authors would like to thank Shigeo Hayashi and Masamichi Matsudaira of The Medical and Pharmacological Research Center Foundation for their technical support and the staff of the Department of Neurology of Kanazawa University Hospital for their clinical support.
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