Data from: Flortaucipir PET uncovers relationships between tau and β-amyloid in aging, primary age related tauopathy, and Alzheimer disease

[18F]-Flortaucipir PET is considered a good biomarker of Alzheimer’s
disease. However, it is unknown how flortaucipir is associated with the
distribution of tau across brain regions and how these associations are
influenced by β-amyloid. It is also unclear whether flortaucipir can
detect tau in definite primary age-related tauopathy (PART). We identified
248 individuals at Mayo Clinic that had undergone [18F]-flortaucipir PET
during life, had died, and undergone an autopsy, 239 cases of which also
had β-amyloid PET. We assessed nonlinear relationships between
flortaucipir uptake in nine medial temporal and cortical regions, Braak
tau stage and Thal β-amyloid phase using generalized additive models. We
found that flortaucipir uptake was greater with increasing tau stage in
all regions. Increased uptake at low tau stages in medial temporal regions
was only observed in cases with high β-amyloid phase. Flortaucipir uptake
linearly increased with β-amyloid phase in medial temporal and cortical
regions. The highest flortaucipir uptake occurred with high Alzheimer’s
disease neuropathologic change (ADNC) scores, followed by low-intermediate
ADNC scores, then PART, with entorhinal cortex providing the best
differentiation between groups. Flortaucipir PET had limited ability to
detect PART and imaging defined PART did not correspond with
pathologically defined PART. In summary, spatial patterns of flortaucipir
mirrored histopathological tau distribution, were influenced by β-amyloid
phase, and were useful for distinguishing different ADNC scores and PART.