Tau PET: utility as a biomarker for chronic traumatic encephalopathy

Abstract

AbstractBackgroundChronic traumatic encephalopathy (CTE) is a neurodegenerative disease characterized by tau deposition in the depths of the sulci associated with exposure to repetitive head impacts (RHI). It is a post‐mortem diagnosis. We previously reported a frontotemporal predominant tau 18F‐MK6240 PET pattern resembling the distribution of CTE in a retired Australian Rules Football player in the context of a moderate amyloid‐beta plaque burden.1 This study aimed to investigate the utility of 18F‐MK6240 PET as a potential biomarker for CTE in contact sports players with exposure to RHI (sRHI).MethodsRHI (n = 33) and age‐matched healthy controls (HC) (n = 32) completed amyloid (18F‐NAV4694) and tau (18F‐MK6240) PET scans. Amyloid PET was quantified in Centiloids. 18F‐MK240 standardized uptake value ratios (SUVRs) were generated for the dorsolateral prefrontal cortex and composite regions of interest (ROI) (frontal; mesial temporal; temporoparietal).ResultFor sRHI, the primary contact sport was Australian Rules Football (n = 17), boxing/kickboxing/martial arts (n = 11), rugby (n = 4) and soccer (n = 1), with 36.4% participating at a professional level. sRHI had a mean age of 54.2 (±9.2) (vs HC 53.0±9.5, p = 0.61), and 94% were male (vs HC 78%, p = 0.08). sRHI did not differ from HC in years of education (p = 0.46) but had more impaired MMSE (28.1±1.9 vs 29.3±0.8, p = 0.006, d = ‐0.80) and Clinical Dementia Rating scores (0.21±0.3 vs 0±0, p<0.001, d = 1.25). sRHI and HC did not differ in mean Centiloid values (2.9±8.4 vs 3.0±8.2). sRHI and HC did not differ in 18F‐MK6240 SUVR in the regions examined, and no differences were observed between professional and amateur sRHI.ConclusionContact sports players with exposure to repetitive head impacts did not differ from age‐matched healthy controls on 18F‐MK6240 SUVR in frontal, mesial temporal, and temporoparietal brain regions. Study limitations include the small sample size, heterogeneity in sports type and highest level of participation, and participants with relatively mild cognitive and functional impairments. Additionally, while 18F‐MK6240 has high affinity for 3R/4R tau in Alzheimer’s disease, its affinity in CTE, particularly important at early stages, remains unclear.