In patients with a baseline diagnosis of AD and an inconsistent PET scan, 100% (28/28) changed their diagnosis to non-AD after a negative amyloid-PET, and 76% (35/46) changed to non-AD after a negative tau-PET, denoting a statistically stronger impact of a negative amyloid-PET versus a negative tau-PET (χ2 = 6.1, p = 0.014). Here, MAPT is linked to Alzheimer disease.