Traumatic brain injury (TBI) is a worldwide source of disability that often affects young adults. For example, in the USA, 1.4 million people are injured every year and approximately 5.3 million individuals currently suffer long-term neurocognitive deficits induced by TBI. Of these new injuries, approximately 80% of them have unremarkable head computed tomography (CT) and routine brain magnetic resonance imaging (MRI).[1] The current lack of definitive imaging findings using conventional neuroimaging techniques makes the objective determination, evaluation, and categorization of TBI fraught with difficulty and leads to disparity between the available subjective measures and clinical outcomes.

The current diagnosis of TBI is made on subjective measures of clinical history and neuropsychological testing, with severity classification based on Glasgow Coma Scale, loss of consciousness, and post-traumatic amnesia. Response to therapy or intervention is also based upon these subjective clinical measures. Early objective measures that can determine not only the presence of mild TBI but also more precisely classify the severity of the injury are desirable. Within the current medical imaging armamentarium, the multimodal capability of MRI makes this the most likely and promising candidate to meet these objective neuroimaging goals.