Incremental Diagnostic Value of Tau-PET With [18F]RO948 vs Amyloid-PET in Patients With Cognitive Impairment

Inclusion Criteria: * Written Inform Consent to participating. * 50 to 85 years of age * a diagnosis of Mild Cognitive Impairment (MCI=at least one pathological neuropsychological test but no functional impairment based on the Amsterdam IADL score) or mild dementia (both cognitive and functional impairments) * availability of MRI within 6 months before screening * prescription of a diagnostic amyloid PET * Willing and able to comply with the requirements of the study, as judged by the investigator. Exclusion Criteria: * The presence of psychiatric disorders, extensive white matter lesions or other stigmata of vascular dementia. * Visual and auditory acuity inadequate for neuropsychological testing. * Enrolment in previous clinical trials for AD potentially affecting amyloid and/or tau brain load * Enrolment in other trials or studies not compatible with \[18F\]RO948 Imaging study. * Ferromagnetic implants and devices (including implants or devices held in place by sutures, granulation or ingrowth of tissue, fixation devices, or by other means) not eligible for MRI scanning. * Women of childbearing potential must not be pregnant (negative urine β-hCG on the day of imaging) or breast feeding at screening