Multimodal in vivo and postmortem assessments of tau in Lewy body disorders.

ABSTRACT

We compared regional retention of 18F-flortaucipir between 20 patients with Lewy body disorders (LBD), 12 Alzheimer's disease patients with positive amyloid positron emission tomography (PET) scans (AD+Aß) and 15 healthy controls with negative amyloid PET scans (HC-Aß). In LBD subjects, we compared the relationship between 18F-flortaucipir retention and cerebrospinal fluid (CSF) tau, cognitive performance, and neuropathological tau at autopsy. The LBD cohort was stratified using an Aß42 cut-off of 192 pg/mL to enrich for groups likely harboring tau pathology (LBD+Aß = 11, LBD-Aß = 9). 18F-flortaucipir retention was higher in LBD+AB than HC-Aß in five, largely temporal-parietal regions with sparing of medial temporal regions. Higher retention was associated with higher CSF total-tau levels (p = 0.04), poorer domain-specific cognitive performance (p = 0.02-0.04), and greater severity of neuropathological tau in corresponding regions. While 18F-flortaucipir retention in LBD is intermediate between healthy controls and AD, retention relates to cognitive impairment, CSF total-tau, and neuropathological tau. Future work in larger autopsy-validated cohorts is needed to define LBD-specific tau biomarker profiles.