Investigating the feasibility of 18F-flortaucipir PET imaging in the antemortem diagnosis of primary age-related tauopathy (PART): An observational imaging-pathological study

Abstract

Introduction: Primary age-related tauopathy (PART) is characterized by neurofibrillary tangles and minimal β-amyloid deposition, diagnosed postmortem. This study investigates ¹⁸F-flortaucipir (FTP) PET imaging for antemortem PART diagnosis.

Methods: We analyzed FTP PET scans from 50 autopsy-confirmed PART and 13 control subjects. Temporal lobe uptake was assessed both qualitatively and quantitatively. Demographic and clinicopathological characteristics and voxel-level uptake using SPM12 were compared between FTP-positive and FTP-negative cases. Intra-reader reproducibility was evaluated with Krippendorff's alpha.

Results: Minimal/mild and moderate FTP uptake was seen in 32% of PART cases and 62% of controls, primarily in the left inferior temporal lobe. No demographic or clinicopathological differences were found between FTP-positive and FTP-negative cases. High intra-reader reproducibility (α = 0.83) was noted.

Discussion: FTP PET imaging did not show a specific uptake pattern for PART diagnosis, indicating that in vivo PART identification using FTP PET is challenging. Similar uptake in controls suggests non-specific uptake in PART.

Highlights: ¹⁸F-flortaucipir (FTP) PET scans were analyzed for diagnosing PART antemortem. 32% of PART cases had minimal/mild FTP uptake in the left inferior temporal lobe. Similar to PART FTP uptake was found in 62% of control subjects. No specific uptake pattern was found, challenging in vivo PART diagnosis.

Keywords: 18F‐flortaucipir PET; PART; definite PART; primary age‐related tauopathy; tau‐PET.