VISUALLY-RATED STRUCTURAL MRI PROFILES IN NEUROPATHOLOGICALLY-CONFIRMED CHRONIC TRAUMATIC ENCEPHALOPATHY

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease that can currently only be diagnosed through neuropathological examination. It cannot be diagnosed during life at this time due in part to the lack of validated in vivo biomarkers. Structural magnetic resonance imaging (MRI) is an integral component of the clinical evaluation and diagnosis of neurodegenerative diseases. Yet, structural MRI patterns in CTE are unknown. The objective of this study was to characterize the structural MRI patterns of CTE by comparing visually-rated macrostructural features on clinical MRIs between deceased individuals with autopsy-confirmed CTE and cognitively normal participants. The sample included 35 deceased individuals neuropathologically diagnosed with CTE and 50 cognitively normal participants from the Boston University Alzheimer's Disease Center Registry. Participants were ³60 years. Clinical MRIs were obtained through medical record requests. Three radiologists (two neuroradiologists) used established five-point (0=absent, 4=severe) visual rating scales to rate regional atrophy on T1 sequences and microvascular disease on T2-FLAIR. Presence of cavum septum pellucidum (CSP) was rated. Raters were trained on the scales using two practice sets and were blinded to case/control status during test ratings. Majority consensus rating was used; in the absence of majority, median was used. All p-values were false discovery rate (FDR)-corrected. All participants with CTE were American football players (Table 1). Table 2 provides a summary of results. Ordinal regressions showed those with CTE had significantly increased odds for more severe frontal and temporal lobe atrophy, larger lateral and third ventricles, as well as thinner genu and splenium of the corpus callosum. Binary logistic regression showed those with CTE had a 9.96X (95% CI=1.60-62.20) increased odds for having an anterior CSP. There were no statistically significant effects for parietooccipital regions.