Diffusion MR proves adept at predicting concussion outcomes

Diffusion tensor MRI can be used to separate concussion patients who are likely to fully recover within a year from those who are likely to suffer longer-term effects, pointing to the most appropriate treatment pathways for each.

The technology can also show how it is that the healing brain repairs itself or compensates for this form of mild traumatic brain injury (mTBI).

The prospective, longitudinal study behind these conclusions, lead-authored by Sara Strauss, MD, of Albert Einstein College of Medicine in New York, was published online June 9 in the American Journal of Neuroradiology.

Diffusion tensor imaging (DTI) tracks water molecules moving along axons, the nerve fibers in white matter, which allowed the team to measure fractional anisotropy (FA) throughout the brain.

FA reflects the degree to which diffusion of the water molecules tends to occur in one direction rather than scattering in many.

In a low FA brain region, damage due to brain injury may be impeding water movement.

In their study report, Strauss and colleagues describe their work performing DTI on 39 patients diagnosed with mTBI in the emergency department within 16 days of the initial injury.

They compared these results with those from a control group made up of 40 healthy participants and assessed the concussion patients for cognitive function, post-concussion symptoms and quality-of-life measures.

A year later, DTI comparing 26 concussion patients with the control group turned up two categories of white-matter abnormality in the patients.

One category showed abnormally low FA, which was associated with axon damage and cognitive deficit.

The other showed abnormally high FA, which was associated with better outcomes in follow-up assessments.

In their discussion, Strauss et al. conclude that both brain-wide and regional individualized quantification of microstructural changes shortly following mTBI are associated with prediction-affirming outcomes at one year after injury.

The authors add that they further “support the hypothesis that [abnormally high FA] may be a marker of compensatory neural mechanisms and harbinger of favorable outcome, which may open new avenues toward TBI treatment.”

In a press release, senior author Michael Lipton, MD, PhD, says that 70 to 85 percent of concussion patients get better on their own, “which makes it difficult to learn whether any treatment is actually helping. Our imaging technique allows researchers to test potential therapies on those concussion patients who can truly benefit from them.”

Lipton cautions that more studies are needed to validate the use of DTI as an early predictor of concussion outcomes.

The medical school has posted to YouTube a five-minute video of Lipton discussing the research.