MAPT and Alzheimer disease: The aims of this study were thus to investigate the association between CSF tau levels, derived from both commercial assays (P-tau181p and T-tau) [8, 9] and novel assays, the latter including N-terminus plus mid-domain regions (tau N-Mid) and C-terminally truncated tau (tau-368), and longitudinal findings using the tau PET tracer [18F]THK5317 [(S)-[18F]THK5117] [12–14] and [18F]FDG in a sample of patients with AD.