Fig. 2

Normal patterns of cerebral uptake across multiple radiotracers. Fluorodeoxyglucose PET/CT demonstrates high-grade uptake in the cortical and deep gray matter which should be greater than cerebellum (a). Cerebral blood flow imaging with early-frame or dynamic amyloid agents shows a similar pattern to FDG (b). Non-specific low-grade white matter activity with absence of gray matter activity is the normal pattern of delayed amyloid PET agents (c). Normal distribution of tau agents is low-grade gray and white matter activity with absence of elevated neocortical uptake and a variable amount of off-target binding, commonly involving the basal ganglia and choroid plexuses (arrows in d)