The purpose of this study is to evaluate High Definition Fiber Tracking (HDFT), an MRI-based diagnostic method. Imaging results will be compared to neuropsychological testing results to potentially 'map' areas of damage following a TBI. The University of Pittsburgh Medical Center is the lead institution on this study under the direction of David Okonkwo, MD PhD, with TBI patients being enrolled at specific TRACK-TBI clinical sites that possess the requisite HDFT imaging capabilities.