The aim of this multimodal study was to assess the binding properties of two chemically different tau-specific PET tracers (11C-THK5351 and 11C-PBB3) in vivo when injected into the same patients on the same day, and to examine their relationship with markers of amyloid-beta deposition, cognitive impairment and measures of cerebrospinal fluid (CSF) tau and medial temporal atrophy. Here, MAPT is linked to Cognitive impairment.