MAPT and Atrophy: Then, for tracers such as [18F]FDG-PET which are highly related to the underlying brain anatomy (Horwitz et al. 1984) and correlate with local GM atrophy and Tau deposition, by contrast to amyloid tracers (Bischof et al. 2016; La Joie et al. 2012; Villain et al. 2010), it can be expected that the PVEc causes the global PET signal to be more homogeneous across subjects and groups.