[18F]-florbetaben PET/CT imaging in the Alzheimer's disease mouse model APPswe/PS1dE9.

BACKGROUND: Positron-emission-tomography (PET) using 18F labeled florbetaben allows non-invasive in vivo-assessment of amyloid beta (Aβ), a pathological hallmark of Alzheimer's disease (AD). In preclinical research, [18F]-florbetaben-PET has already been used to test the amyloid-lowering potential of new drugs, both in humans and in transgenic models of cerebral amyloidosis. The aim of this study was to characterize the spatial pattern of cerebral uptake of [18F]-florbetaben in the APPswe/PS1dE9 mouse model of AD in comparison to histologically determined number and size of cerebral Aβ plaques.

METHODS: Both, APPswe/PS1dE9 and wild type mice at an age of 12 months were investigated by small-animal PET/CT after intravenous injection of [18F]-florbetaben. Highresolution magnetic resonance imaging data were used for quantification of the PET data by volume of interest analysis. The standardized uptake values (SUVs) of [18F]-florbetaben in vivo as well as post mortem cerebral Aβ plaque load in cortex, hippocampus and cerebellum were analyzed.

RESULTS: Visual inspection and SUVs revealed an increased cerebral uptake of [18F]- florbetaben in APPswe/PS1dE9 mice compared with wild type mice especially in the cortex, the hippocampus and the cerebellum. However, SUV ratios (SUVRs) relative to cerebellum revealed only significant differences in the hippocampus between the APPswe/PS1dE9 and wild type mice but not in cortex; this differential effect may reflect the lower plaque area in the cortex than in the hippocampus as found in the histological analysis.

CONCLUSION: The findings suggest that histopathological characteristics of Aβ plaque size and spatial distribution can be depicted in vivo using [18F]-florbetaben in the APPswe/PS1dE9 mouse model.