MAPT and Alzheimer disease: Despite tau PET remains as a powerful research tool in tauopathies, we suggest to consider the use of 18F-flortaucipir PET imaging in the following clinical scenarios: the cause of cognitive impairment remains uncertain after a comprehensive clinical evaluation by an expert; the disease history and routine examination cannot confirm the definitive diagnosis of AD (as it would be possible, e.g., in familial AD); there is a need to differentiate AD from other neurodegenerative tauopathies; there is a need to determine the severity of tau deposition in AD.