In vivo cortical spreading pattern of tau and amyloid in the Alzheimer disease spectrum

To determine the in vivo cortical spreading pattern of tau and amyloid and to establish positron emission tomography (PET) image-based tau staging in the Alzheimer disease (AD) spectrum.

We included 195 participants (53 AD, 52 amnestic mild cognitive impairment [MCI], 23 nonamnestic MCI, and 67 healthy controls) who underwent 2 PET scans ((18) F-florbetaben for amyloid-β and (18) F-AV-1451 for tau). We assumed that regions with earlier appearances of pathology may show increased binding in a greater number of participants and acquired spreading order of tau accumulation by sorting the regional frequencies of involvement. We classified each participant into image-based tau stage based on the Z score of the composite region for each stage.