APOE and dementia: Correspondingly, Maetzler et al. (2009) identified that all their subjects positive for amyloid-beta (via [11C]-PiB PET), measured in their frontal brain regions, posterior cingulate, as well as in superior parietal, lateral temporal and occipital lobe, had dementia (PDD and DLB) and a higher prevalence of APOE4 when compared to non-demented and demented subjects negative for [11C]-PiB (Maetzler et al., 2009).