Imaging Concussion: A Review

Concussion is a significant public health problem that is receiving increased attention from physicians, the media, and the public. Recent studies suggest that persistent symptoms after concussion/mild traumatic brain injury (mTBI) may arise from structural or metabolic alterations in the brain, despite normal conventional neuroimaging studies. New, advanced neuroimaging techniques show promise in refining diagnosis and outcome prediction in concussion/mTBI. Here, we review some of these techniques, including diffusion tensor imaging, task-based and resting-state functional magnetic resonance imaging, as well as positron emission tomography, H magnetic resonance spectroscopy, and perfusion imaging. Although further validation is needed through large prospective studies that correlate these techniques with patient outcome, it is likely that the definitions of pathoanatomic lesions, and a better understanding of their relationship to symptoms and prognosis, will continue to evolve as neuroimaging techniques continue to progress. ABBREVIATIONS:BOLD, blood oxygen level-dependentDMN, default mode networkFA, fractional anisotropyF-FDG,F-fluorodeoxyglucosefMRI, function magnetic resonance imagingGOS-E, extended Glasgow Outcome ScaleGCS, Glasgow Coma ScaleLOC, loss of consciousnessMD, mean diffusivityMRS, magnetic resonance spectroscopymTBI, mild traumatic brain injuryNAA, N-acetylaspartateROI, region of interestrs, resting stateSPECT, single-photon emission computed tomography