Regional analysis of striatal and cortical amyloid deposition in patients with Alzheimer's disease.

We aimed to analyse the detailed distribution pattern of amyloid-β (Aβ) in the striatum, and to examine whether there is any correlation between Aβ deposition levels in the striatum and cortical regions. Twenty patients with Alzheimer's disease underwent positron emission tomography using (11) C-Pittsburgh Compound B ((11) C-PiB) to quantify the Aβ deposition. Volumes-of-interest analyses were performed on the ventral striatum (VST), pre-commissural dorsal caudate (pre-DCA), post-commissural caudate (post-CA), pre-commissural dorsal putamen (pre-DPU), and post-commissural putamen (post-PU), followed by exploratory voxel-wise analyses. Volumes-of-interest analyses of (11) C-PiB binding showed: VST > pre-DPU (P = 0.004), VST > pre-DCA (P < 0.0001), pre-DPU > post-PU (P < 0.0001), and pre-DCA > post-CA (P < 0.0001), consistent with visual inspection of the (11) C-PiB images. Exploratory voxel-wise analyses of (11) C-PiB binding showed a positive correlation between the VST and the medial part of the orbitofrontal area (P < 0.01 family-wise error corrected). This study confirmed that there were ventral > dorsal, and anterior > posterior gradients of Aβ deposition in patients with Alzheimer's disease, and provided the first evidence of a robust correlation between Aβ deposition levels in the VST and the medial part of the orbitofrontal area. There are well-known anatomical and functional links between these areas. These findings indicated that brain Aβ deposition was not randomly distributed, but had characteristic patterns related to anatomical connectivity and/or functional networks.