In preliminary findings, Saint Louis University researchers report that veterans who suffered blast injuries have changes in brain tissue that are still apparent in images years after the blast. The data, presented at the annual meeting of the Radiological Society of North America, represents a small but intriguing look at brain imaging in those who suffered combat-related head injuries.
The findings are some of the first to come from a U.S. Department of Defense-funded brain imaging grant to Saint Louis University to learn more about the nature of traumatic brain injury (TBI) in veterans and civilians. The imaging project, led by Richard Bucholz, M.D., professor and vice chairman in the department of neurosurgery at SLU, began recruiting participants in 2009 and is concluding this year.
This study looked at data from diffusion tensor imaging, a type of highly sensitive magnetic resonance image (MRI), used to examine the way water moves throughout the brain's white matter.
SLU researcher Tom Malone compares the way water moves along nerve fibers through the brain to a garden hose.
"Imagine that water moving through a healthy brain is like a functional garden hose, all moving in the same direction with no leaks," said Malone. "Then, imagine a hose with many small holes in it, leaking water along the way. That's analogous to what we're seeing in the DTI scans of brains of those with blast injuries."
In civilians who suffered mild traumatic brain injury, like a concussion, cognitive issues typically resolved within one to three months. Military patients, however, often reported more persistent issues.
"Our military participants were still reporting problems," said P. Tyler Roskos, a neuropsychologist and assistant professor in the department of neurosurgery at SLU.
"They look normal on a battery of cognitive tests. But when they went through our imaging tests we saw differences in their scans."
It is possible that previous scans were not sensitive enough to pick up these changes to the brain. Or, it may be the case that some veterans have more complicated health issues, Roskos says.
"Sometimes combat veterans are dealing with multiple challenges, like depression or alcohol or drug use. It can be hard to tell what's causing what."
"The difficult thing with this group is that many times service members don't receive evaluation until they are back stateside," said Roskos. "We know that if you do a CT or standard MRI scan, you probably won't see anything abnormal. And yet, injured service members are frequently reporting problems with memory, functioning or daily life. And, until now, we've had limited data to try to understand what's going on.
"The diffusor tensor imaging has the potential to help us understand why injured members of the military are reporting these issues. It also may help service members feel justified that the 'invisible injuries' they experience are real."
Saint Louis University School of Medicine