Abstract
Objective Chronic traumatic encephalopathy (CTE) 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-β plaque burden.1 This study investigated 18F-MK6240 as a potential CTE biomarker in contact sports players with exposure to repetitive head impacts (sRHI).
Methods 33 sRHI and 32 age-matched healthy controls (HC) completed amyloid 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).
Results For sRHI, the primary contact sport was Australian Rules Football (n=17), boxing/kickboxing/martial arts (n=11), rugby (n=4) and soccer (n=1); 36.4% played professionally. sRHI had a mean age of 54.2 (±9.2) (vs HC 53.0±9.5, p=0.61). 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 Centiloids or 18F-MK6240 SUVRs across all ROIs.
Conclusions Contact sports players with exposure to repetitive head impacts did not differ from controls in terms of brain tau burden. Limitations: 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.
Reference
Krishnadas N, et al. Case report: 18F-MK6240 tau positron emission tomography pattern resembling chronic traumatic encephalopathy in a retired Australian Rules Football player. doi.org/10.3389/fneur.2020.598980.
