Combined Quantitative Diffusion Tensor and 1H Magnetic Resonance Spectroscopic Imaging Findings in Patients with Persistent Neurocognitive Deficits Following a Mild Traumatic Brain Injury.

Brenda Bartnik Olson¹, Kimberly Conley², Karen Tong¹, Sarah Uffindell³, Valerie Wong⁴, Barbara Holshouser¹

Neurocognitive deficits occur in approximately 50-80% of mild TBI patients, which may persist for several years after injury even though conventional imaging is normal. In this study we used diffusion tensor and 1H magnetic resonance spectroscopic imaging to evaluate if microstructural and/or metabolic abnormalities are present in mTBI subjects with persistent neurocognitive deficits. Our findings show that regions of neuronal loss or dysfunction are present in the left anterior internal capsule and left occipital white matter of mild TBI patients. In addition, increased fractional anisotropy in the left anterior internal capsule may be related to an increase in extracellular space adjacent to remaining axons after the loss of a subset of corticospinal tract fibers. Our findings suggest that both metabolic and ultrastructural changes persist following a mild TBI which may relate to continued neurocognitive deficits seen in these subjects.