Participant Selection and Neuropathological Diagnosis

We searched the University of California, San Francisco, Memory and Aging Center (UCSF MAC) database for all patients with at least 1 MRI study (N = 4479). We excluded 4133 participants without a neuropathological diagnosis or with low-quality MRI. In patients with multiple MRI studies, we selected the first study suitable for analysis regardless of the diagnosis at MRI. This search identified a consecutive series of 326 participants with an MRI suitable for analysis and neuropathological data spanning all major neuropathological diagnoses: AD, PD, PD with Lewy body dementia, FTLD, and cerebrovascular disease. FTLD cases were further classified based on the consensus nomenclature for FTLD.^25,26,27 Brain autopsies were performed at different brain banks following previously published methods.¹⁶ For the aims of this study, 3 main groups of interest were defined: PSP (68 participants), CBD (44 participants), and other pathologies (214 participants, including all other pathologies). Group details are shown in Table 1.

Abbreviations: 4RT, four-repeat tau isoform tauopathies; AD, Alzheimer disease; CBD, corticobasal disease; CBS, corticobasal syndrome; FTLD, frontotemporal lobar degeneration; LBD, Lewy body dementia; MMSE, Mini-Mental State Examination; MND, motor neuron disease; MRI, magnetic resonance image; MSA, multiple-system atrophy; PD, Parkinson disease; PSP, progressive supranuclear palsy; PSP-RS, progressive supranuclear palsy with Richardson syndrome; TDP, TAR DNA binding protein 43.

This study followed the Standards for Reporting Diagnostic Accuracy (STARD) reporting guideline. The study was approved by the UCSF institutional review board and was conducted following the Declaration of Helsinki,²⁸ and written informed consent was obtained from all participants.