UCSF

Mild traumatic brain injury (mTBI) is a major public health concern, linked with post-concussive syndrome and chronic traumatic encephalopathy. At present, standard clinical imaging fails to reliably detect traumatic axonal injury associated with mTBI and post-concussive symptoms. Diffusion tensor imaging (DTI) is an MR imaging technique that is sensitive to changes in white matter microstructure. Prior studies using DTI to investigate mTBI did not separate contact sport athletes, a population at high risk for mTBI and subconcussive head traumas, and there has been a dearth of longitudinal studies of mTBI patients. In this study, we used Tract-Based Spatial Statistics to perform cross-sectional and longitudinal analysis describing changes in DTI scalar parameters in emergency room (ER) patients and in scholastic contact sport athletes. In the acute post-injury period, athletes demonstrated an elevated rate of regional decreases in axial diffusivity compared to controls. These decreases were especially pronounced in the cerebellar peduncles, and were more pronounced in contact sport athletes compared to the ER patient population. These results lend credence to the hypothesis that post-concussive symptoms are caused by shearing of axons of an attention network in the brain with timing mediated by the cerebellum, and warrant further study of the correlation between cerebellar DTI findings and clinical outcomes in mTBI patients.