The Silent Effects of Concussions

Concussion patients showed reduced brain blood flow after clinical recovery


That bump on the head may have effects on your brain for longer than you might think.

At least that's what MRI scans suggested in a new study of athletes with sports-related concussions. Even after these athletes had recovered by clinical standards, many still had reduced blood flow in their brains.

A concussion occurs after a severe head impact. These injuries are common to contact sports like boxing and football. Before athletes with concussions can return to play, they have to be medically cleared. Health care providers usually clear athletes based on tangible or visible symptoms, such as headache, confusion, dizziness, nausea and vomiting.

But according to lead study author Yang Wang, MD, PhD, associate professor of radiology at the Medical College of Wisconsin, there's reason to believe that some athletes are returning to play too soon, even though they've been medically cleared. Some are prone to second injuries and further symptoms.

Instead of relying on traditional concussion assessment methods, Dr. Wang and colleagues decided to use MRI technology to scan the brains of 37 young athletes. Eighteen had concussions. They scanned the players' brains within one day of their injuries and than again eight days later to measure changes in blood flow in the brain.

"This measurement of blood flow is fully noninvasive, without radiation exposure," Dr. Wang said in a press release. "We use arterial blood water as a contrast tracer to measure blood flow change, which is highly associated with brain function."

Based on traditional concussion assessment, the players with concussions were back to normal function eight days after their injuries. But when Dr. Wang and team scanned the players' brains at day eight, they found evidence that brain blood flow was still compromised.

"In eight days, the concussed athletes showed clinical recovery," Dr. Wang said. "However, MRI showed that even those in clinical recovery still had neurophysiological abnormalities. Neurons under such a state of physiologic stress function abnormally and may become more susceptible to second injury."

Dr. Wang and colleagues didn't look into exactly why blood flow in the brain was reduced in concussed athletes, but they did note that MRI scans could one day have a place in concussion diagnosis and treatment. The team is currently conducting more research on this subject.

This study was presented Nov. 30 at the 2015 meeting of the Radiological Society of North America. Research presented at conferences may not have been peer-reviewed.

Information on funding sources and conflicts of interest was not available at the time of publication.