Longitudinal and prognostic evaluation of mild traumatic brain injury: A 1H-magnetic resonance spectroscopy study.

In the majority of mild traumatic brain injury (mTBI) cases, brain tissue impairment is undetectable by computed tomography and/or structural magnetic resonance imaging (MRI). Even in confirmed cases of head injury, conventional neuroimaging methods lack sensitivity in predicting neuropsychological outcomes of patients. The objectives of this study were to (i) cross-sectionally determine deviations in the neurometabolic profile of mTBI patients from healthy controls at different stages of mTBI using tightly controlled examination windows (ii) determine associations between acute neurometabolic markers of mTBI and chronic neurocognitive performance. Patients were examined at the early sub-acute (n=43; 5.44+3.15 days post injury (DPI)), late sub-acute (n=33; 37.00+12.26 DPI) and chronic (n=27; 195.30+19.60 DPI) stages of mTBI. Twenty-one neurologically intact subjects were used as controls. Proton magnetic resonance spectroscopy imaging (1H-MRSI) was used to obtain metabolic measurements from different brain regions. The Automated Neuropsychological Assessment Metrics (ANAM) was used for cognitive evaluation of patients at the chronic stage of mTBI. Measurements in the thalamus and centrum semiovale (CSV) emerged as the most indicative of injury and were used to predict neurocognitive outcome. The major findings of this study are (i) decreases in Cho/Cre (choline-to-creatine ratio) measured in the thalamus (p=0.042) and CSV (p=0.017) at the late sub-acute stage of mTBI (ii) positive associations of early sub-acute Cre measurements in the CSV with chronic ANAM scores measuring performance in delayed (r=0.497, p=0.019) and immediate (r=0.391, p=0.072) code substitution. These findings show that metabolic measurements in the thalamus and CSV can potentially serve as diagnostic and prognostic markers of mTBI. Language: en