Tag Archives: MRI
Some athletes who experience sports-related concussions have reduced blood flow in parts of their brains even after clinical recovery, according to a study presented today at the annual meeting of the Radiological Society of North America (RSNA). The results suggest a role for MRI in determining when to allow concussed athletes to return to competition.
Concussions affect millions of people each year and are especially prevalent in contact sports like football. Sports are second only to motor vehicle crashes as the leading cause of traumatic brain injury among people between 15 and 24 years old, according to the National Institutes of Health.
Decisions to clear concussed athletes to return to action are typically based on symptoms and cognitive and neurological test results. However, there is increasing evidence that brain abnormalities persist beyond the point of clinical recovery after injury.
To find out more, researchers from the Medical College of Wisconsin in Milwaukee studied concussed football players with arterial spin labeling, an advanced MRI method that detects blood flow in the brain.
“This measurement of blood flow is fully noninvasive, without radiation exposure,” said study author Yang Wang, M.D., Ph.D., associate professor of radiology at the Medical College of Wisconsin. “We use arterial blood water as a contrast tracer to measure blood flow change, which is highly associated with brain function.”
Dr. Wang and colleagues studied 18 concussed players and 19 non-concussed players. They obtained MRI of the concussed players within 24 hours of the injury and a follow-up MRI eight days after the injury and compared results with those of the non-concussed players. Clinical assessments were obtained for both groups at each time point, as well as at the baseline before the football season.
The concussed players demonstrated significant impairment on clinical assessment at 24 hours post-injury, but returned to baseline levels at eight days. In contrast to clinical manifestation, the concussed players demonstrated a significant blood flow decrease at eight days relative to 24 hours post-injury, while the non-concussed players had no change in cerebral blood flow between the two time points.
“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.”
While the reasons for reduced cerebral blood flow in concussed athletes are still under investigation, the findings may have important implications for decisions on when athletes are ready to return to play after head injuries, according to the study’s principal investigator, Michael McCrea, Ph.D., professor of neurosurgery and neurology and director of brain injury research the Medical College of Wisconsin.
“For years, we’ve relied on what athletes are telling us,” Dr. McCrea said. “We need something more objective, and this technology may provide a greater measurement of recovery.”
The Medical College of Wisconsin scientists are continuing their research as one of the Phase II winners of the Head Health Challenge, an initiative from the National Football League and General Electric to develop ways to speed diagnosis and improve treatment for concussion. Dr. McCrea and his team are also co-chairing the Concussion Assessment, Research and Education Consortium (CARE) project, a major national effort that will enroll more than 30,000 college athletes, making it the largest study of concussions to date.
“The nature of this research allows us to study the mechanisms of injury and recovery directly in humans rather than in animal models,” Dr. McCrea said. “Our ultimate aim is to better understand the time course of neurobiological recovery after concussion.”
Other co-authors on the study are Lindsay D. Nelson, Ph.D., Ashley A. LaRoche, Adam Y. Pfaller, B.S., Andrew S. Nencka, Ph.D., andKevin M. Koch, Ph.D.
A new MRI study has found distinct injury patterns in the brains of people with concussion-related depression and anxiety, according to a new study published online in the journal Radiology. The findings may lead the way to improved treatment and understanding of these common disorders, researchers said.
Post-concussion psychiatric disorders like depression, anxiety and irritability can be extremely disabling for those among the nearly 3.8 million people in the United States who suffer concussions every year. The mechanisms underlying these changes after concussion–also known as mild traumatic brain injury–are not sufficiently understood, and conventional MRI results in most of these patients are normal.
For the new study, researchers from the University of Pittsburgh Medical Center (UPMC) in Pittsburgh used diffusion tensor imaging (DTI), an MRI technique that measures the integrity of white matter–the brain’s signal-transmitting nerve fibers–to see if injuries to the nerves may be the root cause of these post-traumatic depression and anxiety symptoms.
The researchers obtained DTI and neurocognitive testing results for 45 post-concussion patients, including 38 with irritability, 32 with depression and 18 with anxiety, and compared the results with those of 29 post-concussion patients who had no neuropsychiatric symptoms.
“Using other concussion patients as our controls was a big advantage of our study,” said lead author Lea M. Alhilali, M.D., assistant professor of radiology at UPMC. “When you are able to study a similar population with similar risk factors, you get much more reliable results.”
The researchers saw unique white matter injury patterns in the patients who had depression or anxiety. Compared to controls, patients with depression had decreased fractional anisotropy (FA), a measure of the structural integrity of white matter connections, around an area near the deep gray matter of the brain that is strongly associated with the brain’s reward circuit.
“The regions injured in concussion patients with depression were very similar to those of people with non-traumatic major depression disorder,” Dr. Alhilali said. “This suggests there may be similar mechanisms to non-trauma and trauma-dependent depression that may help guide treatment.”
Anxiety patients had diminished FA in a part of the brain called the vermis that helps modulate fear-related behaviors. Since the vermis has not been associated with dysfunction in non-traumatic anxiety disorders, this finding may indicate that different treatment targets are required for patients with anxiety after trauma, the researchers said.
No regions of significantly decreased FA were seen in patients with irritability relative to the control subjects.
“There are two major implications for this study,” Dr. Alhilali said. “First, it gives us insight into how abnormalities in the brain occur after trauma, and second, it shows that treatments for non-trauma patients with neuropsychological symptoms may be applicable to some concussion patients.”
The study also raises the possibility that some people diagnosed with non-traumatic depression may actually have experienced a subclinical traumatic event at some point earlier in their lives that may have contributed to the development of depression, she noted.
In the future, the researchers hope to compare DTI findings in concussion patients with depression to those of people who have non-trauma-related depressive disorders.
A new study, conducted by scientists at Taipei Medical University Shuang-Ho Hospital in New Taipei City, has revealed that women may have a tougher time recovering their memory than men after a concussion.
The study relied upon functional magnetic resonance imaging (fMRI) scans to study the brains of 30 men and 30 women.
Neuropsychologist Dave Ellemberg, an associate professor who studies brain injuries at the University of Montreal, told the media that “you cannot treat women like you treat men. But in the field of the management of brain injuries, everyone is managed the same. The data mainly comes from men, and the management programs are all based on evidence that comes from them.”
The study appears online April 28 issue in the journal Radiology.