Imaging of muscarinic acetylcholine receptors using (+)N-[11C]methyl-3-piperidyl benzilate (11C-3NMPB) in vascular dementia and Alzheimer's disease

In order to clarify the integrity of muscarinic acetylcholine receptor (mAChR) in vascular dementia (VaD) and Alzheimer's disease (AD), PET imaging with (+) N-[11C]methyl-3-piperidyl benzilate (11C-3NMPB) was performed in 12 patients with VaD, 11 patients with AD, and 7 normal controls (NC group). The mAChR binding was compared by the ratios compared with the cerebellum which were calculated from the regions of interest (ROI), and by three-dimensional statistic analysis. Compared with the NC group, mAChR was not significantly reduced in any ROI in AD patients. In those with VaD due to cortical lesions, mAChR was reduced in the infarcted areas. On the other hand, mAChR was significantly reduced in the thalamus and anterior cingulated gyrus, but not in other cerebral cortices in patients with VaD due to subcortical lesions. Accordingly, it is suggested that the mAChR is preserved in the cerebral cortices in patients with VaD due to subcortical lesions as well as in AD patients. (author)