Since 2000, tens of thousands of active duty personnel have been diagnosed with a traumatic brain injury (TBI). Based on blast simulations, researchers expect that axonal injury occurs but remains undocumented by conventional methods. To improve outcomes of TBI-affected individuals, researchers need to better understand what TBI does to the brain. Despite the prevalence of TBI, the understanding of TBI on brain physiology is limited due to a lack of appropriate diagnostic tools. New techniques in MRI diagnostics can allow researchers to leverage existing MRI technology to visualize brain physiology and function with greater detail.In fiscal year 2009, Dr. Brody received an Investigator-Initiated Research Award from the Psychological Health/Traumatic Brain Injury Program to investigate TBI in active duty personnel. This research aimed to validate new diagnostic tools and improve basic understanding of TBI brain physiology. Diffusion tensor imaging (DTI) was used to examine details of axonal injury. Rest-state functional MRI correlation analyses (fcMRI) examined brain function and connectivity across regions. Clinical evaluations of the patients were performed to understand patient outcomes in context of TBI.Sixty-three subjects clinically identified as having TBI and 21 control subjects lacking TBI were examined at Landstuhl Regional Medical Center to validate the use of DTI in acute and long-term assessments. Using the control subjects as a baseline, 61 percent of TBI individuals had one or more abnormalities consistent with traumatic brain axonal injuries. Long-term measurements were taken six to 12 months later on 47 subjects with TBI. DTI screening again demonstrated that 49 percent of TBI individuals had one or more abnormalities, showcasing the ability of DTI to visualize brain trauma. Using the same subject set, researchers also analyzed the resting-state MRI data. The affected TBI individuals, similar to the DTI analyses, revealed increased disruption in the community organization and abnormalities over multiple brain regions, signifying affected brain function.Dr. Brody also investigated the clinical status of the TBI subjects. Six to 12 months after initial enrollment, the same set of 47 subjects were assessed with multiple outcome and standardized neurological examinations. The TBI-impacted patients demonstrated significantly worse disability rates than the control group. Psychiatric assessments revealed more frequent and more severe occurrences of Post-Traumatic Stress Disorder and depression in subjects with TBI.Dr. Brody advanced understanding of TBI by demonstrating the existence of brain differences in many TBI subjects. His research connects TBI with poor outcomes in TBI individuals due to higher levels of disability. The results of this research demonstrate TBI as a potential major factor for negative long-term outcomes of affected personnel. Taken together, TBI has been shown to have clear physiological impacts on the brain and impacts on affected individuals. These findings give concrete direction to the research and medical community to investigate and develop new treatments for affected individuals.