Structural Changes Noted with Diffusion Tensor Imaging
The October issue of the journal Brain includes data from a study which evaluated the use of diffusion tensor imaging (DTI) in patients who have traumatic brain injury (TBI). Such imaging is capable of detecting white matter structural changes, especially to the axons, which are correlated with cognitive deficits.
Research has validated the use of DTI to evaluate the integrity of axons in vivo. The study published evaluated the use of DTI to capture the status of white matter across the spectrum of TBI disease, from mild to severe. The study further investigated the correlation between cognitive functioning and the status of white matter.
Twenty patients with TBI, along with healthy controls, underwent imaging with DTI and testing to assess neuropsychological status. Among the twenty patient participants, disease severity ranged from mild to moderate to severe. DTI data was used to calculate axial diffusivity, radial diffusivity, and fractional anisotropy. The neuropsychological data included evaluation of cognitive domain scores determined by assessment of memory, attention, and executive testing.
In the patients with either moderate or severe disease, decreased fractional anisotropy was noted among all 13 areas of interest. In patients with mild TBI, this was limited to three areas. All cognitive domains were negatively correlated with White Matter Load. Axonal damage was associated with all ranges of TBI; patients with moderate to severe TBI had myelin damage that was irreversible.
This modality appears to provide an objective means to assess the extent of brain injury. It may even be a useful modality for patients who had TBI in the past, in order to better understand the extent of imaging.
This is an important step forward in assessing the extent of brain injury, such as those which cause neurobehavioral impairments, of even the mildest nature. Standard imaging approaches may not be able to detect changes commonly seen with TBI, including diffuse axonal injury.
October 31, 2007 Related topics: Imaging, Diagnostic, Radiology, Psychiatry & Neurology