MAPT and Alzheimer disease: Given that tau PET patterns are focal during the initial stages of AD, (Schöll et al., 2016) show heterogenous patterns of uptake in some individuals (Leuzy et al., 2019;Ossenkoppele et al., 2016;Younes et al., 2024;Young et al., 2022), and have various sources of focal off-target binding such as in choroid plexus, basal ganglia, and meninges (Baker et al., 2019;Harrison et al., 2023;Pascoal et al., 2020), it is possible that MRI-free pipelines may be more prone to errors for tau PET, which is often measured in relatively small regions, compared to more globally distributed amyloid PET.