Medpage today’s John Gever reports that a new MRI innovation called diffusion tensor tractography will allow for improved measurements of multifocal nerve damage within the brain. Researchers share that this technology may help track the progress and help predict outcomes after severe traumatic brain injury. Gever (2008) reports:
In an interview, Dr. Diaz-Arrastia said the goal is to find a good measure for diffuse axonal injury, an “overlooked and understudied” phenomenon that increasingly appears to be an important factor in head-injured patients.
He said it used to be considered a rare form of injury, but mainly because it was hard to see with technologies such as CT imaging.
Recent studies suggest it plays a role in at least half of fatal head injuries,” he added. Diffuse axonal injury may also explain puzzling cases in which people with apparently mild head injuries suffer lingering disability.
Diffusion tensor tractography measures water movement within tissues on the basis of MRI data. When nerve cell axons are damaged, as they frequently are in severe head trauma, they swell, absorbing water from surrounding tissues. That reduces movement of extracellular water.
On the other hand, when axons later die, they release water, thereby increasing extracellular water flows.