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Abstract #1938

Proton MR Spectroscopy Correlates Diffuse Axonal Injury with Post-Concussive Symptoms in Mild Traumatic Brain Injury

Ivan I. Kirov1, Assaf Tal1, James S. Babb1, Joseph Reaume1, Tamara Bushnik2, Teresa A. Ashman2, Steven Flanagan2, Robert I. Grossman1, Oded Gonen1

1Radiology, New York University, New York, NY, United States; 2Rusk Institute of Rehabilitation Medicine, New York University, New York, NY, United States

There are no established biomarkers for mild traumatic brain injury (mTBI), in part because post-concussive symptoms (PCS) are subjective and conventional imaging is typically unremarkable. To test whether diffuse axonal injury (DAI) quantified with three-dimensional (3D) proton magnetic resonance spectroscopic imaging (1H-MRSI) correlated with patients PCS we retrospectively studied 26mTBI patients (mean Glasgow Coma Scale score of 14.7), 1856 years old, 3 55 days post injury and 13 controls. All were scanned at 3 Tesla with T1-andT2-weighted MRI and 3D 1H-MRSI (480 voxels over 360 cm3, ~30% of the brain). On scan day patients completed a symptom questionnaire and those indicating at least one of the most common subacute mTBI symptoms (headache, dizziness, sleep disturbance, memory deficits, blurred vision) were grouped as PCS-positive. Global gray- and white matter (GM/WM) absolute concentrations of N-acetylaspartate (NAA), choline (Cho), creatine (Cr) and myo-inositol (mI) in PCS-positive and PCS-negative patients were compared to age- and gender-matched controls using two-way analysis of variance. The results showed that PCS-negative group (n=11) and controls (n=8) did not differ in any GM or WM metabolite level. The PCS-positive patients (n=15) had lower WM NAA than the controls (n=12): 7.00.6 versus 7.90.5mM (p=0.0007). Global WM NAA, therefore, showed sensitivity to the DAI sequelae associated with common PCS in patients with mostly normal neuroimaging as well as GCS scores. This suggests a potential biomarker role in a patient population in which objective measures of injury and symptomatology are currently lacking.