P2-080: Mapping of amyloid deposition in early- and late-onset Alzheimer's disease

Abstract

Previous PET studies have demonstrated that there are differences in cerebral metabolic impairment and acetylcholinesterase activity between early- (EOAD) and late-onset Alzheimer's disease (LOAD).1, 2 Sixteen healthy volunteers (HV: 8M and 8F, 65 ± 10 y.o.), 7 patients with EOAD (4M and 3F, 61 ± 5 y.o., Mini-mental state examination score 15 ± 5), and 10 patients with LOAD (2M and 8F, 75 ± 5 y.o., MMSE score 20 ± 3) took part in this study. [11C]PIB -PET acquisition was a dynamic sequence of 19 PET scans over a 90-minute period. Regions of interest (ROI) were placed in the frontal, temporal, parietal , and occipital cortices, posterior cingulate, striatum and cerebellar cortex. Logan graphical analysis was employed to yield estimates of distribution volume (DV) in each regions using the arterial input function, and DV ratios were calculated in each regions with the cerebellar cortex as a reference tissue. PET images were spatially normalized to the MNI space and voxel-by-voxel DVR in the whole brain was also calculated. Group comparisons of DVR in HVs and two patient groups were performed using ANOVA in SPM5 (uncorrected p<0.0001, cluster extent K50 voxels). DVRs were remarkably increased in the frontal (+49%), lat. temporal (+54%) and lateral parietal cortices (+55%), posterior cingulate (+43%), striatum (+40%) in the EOAD group compared with HVs (Fig. 1a). DVRs were also remakably increased in the frontal (+49%), lateral temporal (+48%), and lateral parietal cortices (+55%), posterior cingulate (+52%), striatum (+35%) in the LOAD group compared with HVs (Fig. 1b). There was no significant difference in DVR in the brain between EOAD and LOAD groups. The results suggest that the degrees and distributions of amyloid deposition in the brain are similar in EOAD and LOAD.