Tau PET Imaging With [18 F]MK‐6240: Limited Affinity for Primary Tauopathies and High Specificity for Alzheimer’s Disease

Abstract Introduction: Second‐generation tau‐PET tracers like [18F]MK‐6240 are increasingly used both for diagnosing and quantifying Alzheimer’s Disease (AD) tauopathy. However, while [18F]MK‐6240 tau‐PET has demonstrated excellent sensitivity for AD tauopathy, data assessing its specificity and binding in non‐AD tauopathies are still scarce. Methods: Participants were assigned to exclusive categorical diagnoses based on their amyloid (Aβ) and cognitive status. We quantified mesiotemporal (MTL) and neocortical [18F]MK‐6240 tau‐PET signal in 28 Aβ− cognitively impaired (CI) patients presenting various non‐AD neurodegenerative disorders. Tau‐PET