Abstract:
Abstract:
Diffuse Axonal Injury (DAI) results from high velocity deceleration and shear strain and is believed to be the predominant mechanism of injury in 40 – 50% of TBIs requiring hospital admission in the US. Diffusion Tensor Magnetic Resonance Imaging (DTI) is a novel imaging technique considered to be a more reliable indicator of DAI than standard structural MRI. DAI is difficult to determine from usual CT scans and, while structural MRI scanning may add some sensitivity, current neuroimaging methods have not been associated with severity of injury or predictive of outcome. The anatomy and integrity of white matter fiber tracts can be determined non-invasively with DTI, providing new information about brain networks and connectivity. While DTI is gaining in popularity, it is not commonly used clinically, in part, due to technical difficulties. Being able to identify specific subtypes of traumatic brain injury (TBI) using DTI may facilitate the design of clinical trials by stratifying patients more likely to respond to a given therapy and may be useful as a surrogate outcome measure.

Fifteen normal subjects and 50 patients with traumatic brain injury, ages 16 or older, will be studied. Normal controls will be family members of the TBI patients or other volunteers who agree to participate in the study. Subjects will be considered for participation in the study if:
A-Normal controls: 1) good general health; 2) ability to provide assent and informed written consent; 3) at least an 8th grade education; 3) normal brain anatomy on magnetic resonance imaging (MRI).
B-Patients with traumatic brain injury: 1) mild, moderate or severe traumatic brain injury as determined with Glasgow Coma Scale; 2) subjects whose primary injury mechanism is DAI (defined by the presence of coma in the absence of focal contusions or intra- or extra-axial hemorrhages; 3) ability to provide assent and informed written consent; and 4) at least an 8th grade education.

Each subject will undergo a neurological examination, laboratory evaluations and MRI scans. Outcome will be assessed from structured questionnaires at six and twelve months after discharge from the hospital. Subjects who meet North Texas TBI Model System inclusion criteria will be enrolled for inclusion into the national database.