CHICAGO—Even after all their symptoms subside, some concussed patients have significantly diminished blood flow to the brain. The arterial spin labeling (ASL) method of fMRI can pinpoint regions affected by the curtailment—and may better guide physicians on when to allow acutely brain-injured athletes to get back on the field.
The study backing up the science was presented Monday in a press conference at the annual meeting of the RSNA.
Using arterial blood water as a noninvasive, endogenous contrast tracer to measure changes in cerebral blood flow, radiologist Yang Wang, MD, PhD, of the Medical College of Wisconsin and colleagues compared fMRI scans of 18 concussed football players with those of 19 uninjured players.
In clinical assessment at 24 hours post-injury, the concussed players evidenced obvious functional impairment.
By eight days later, their cognitive and neurological function had returned to baseline.
However, the ASL-fMRI imaging revealed much reduced cerebral blood flow in the concussed players at eight days relative to their scans 24 hours post-injury, while the non-concussed players had no such change between the two time points.
The tests showed that “even those in clinical recovery still had neurophysiological abnormalities,” said Wang in remarks prepared prior to the press conference. “Neurons under such a state of physiologic stress function abnormally and may become more susceptible to second injury.”
Principal investigator Michael McCrea, PhD, director of brain injury research at the Medical College of Wisconsin, said the explanation for the protracted blood-flow reduction isn’t yet clear and will require further investigation.
But, he stressed, the current findings may be immediately useful.
“For years we’ve relied on what athletes are telling us,” said McCrea. “We need something more objective, and this technology may provide a greater measurement of recovery.”
McCrea and his team are co-chairing the Concussion Assessment, Research and Education Consortium (CARE) project, a national effort slated to enroll more than 30,000 college athletes.
According to the NIH, only vehicular accidents cause more traumatic brain injury than sports in people between 15 and 24 years old.