Noninvasive 'virtual biopsy' diagnoses brain injury

For many, getting hit in the head too many times might bring to mind famed boxer Muhammad Ali, but brain injuries across several sports, including hockey and American football, have prompted investigations into headgear and even the nature of the sports themselves.

For now, the only way to diagnose what is called chronic traumatic encephalopathy (CTE) is to inspect brain tissue during autopsies--in other words, after the point at which such a diagnosis could help the afflicted.

So while results from a study out of Boston of a noninvasive "virtual biopsy" technique on live subjects are both small-scale and preliminary, the potential has CTE researchers talking.

In this study, researchers at Boston University and Harvard University's Brigham and Women's Hospital used a specialized MRI scan (called magnetic resonance spectroscopy) to measure certain chemicals in brain tissue associated with damage.

Specifically, they looked at glutamate, which is neurotoxic and at high levels can kill brain cells, and choline, which is a marker for tissue damage. Among the five retired athletes (three NFL players, a boxer, and a wrestler), who'd been hit several times in the head and exhibited behaviors symptomatic of brain damage, the scans revealed "suspicious chemical changes" in each participant.

"Five subjects is not much to hang a hat on," admits lead author Alexander Lin. But he says his team is already conducting a smaller substudy, and is putting together a larger study that could be "in the hundreds."

The researchers presented their findings this week at the Radiological Society of North America's annual meeting in Chicago.

Because this condition is diagnosed post-mortem, treatments have yet to be developed. But if this imaging technique proves to be accurate, the afflicted can at least be instructed not to return to play in order to prevent further damage, and researchers can begin to study drugs that might slow or even prevent symptoms.

Lin is also working on a parallel study of soldiers returning from Iraq and Afghanistan with traumatic brain injuries, but he says the number of hits in the career of an athlete can trend toward the hundreds, so the groups are likely distinct. "We're trying to understand if it's the number of hits, how big the hits were...Those are questions we'll certainly answer."

Several retired NFL players have signed up to donate their brains to research when they die. It looks like they can now help while they're still alive as larger studies are conducted to measure the imaging technique's efficacy.