MAPT and Alzheimer disease: If a patient in our sample has svPPA due to AD pathology, we expected to see evidence of cortical amyloid, and FTP binding localised congruently with atrophy and at a magnitude consistent with what has been observed in other reports of patients with atypical AD.18 19 If a patient has svPPA due to a primary tauopathy such as Pick’s disease, we expected little or no evidence of cortical amyloid, and low FTP binding consistent with postmortem findings of low or no FTP affinity for straight filament tau.