A study released on concussion patients employing diffusion tensor imaging (DTI) discovered that males took longer to recover following a concussion than females did. Results of the study, which demonstrate that DTI can be used as a bias-free way to foresee concussion outcome, have been published online in the journal Radiology.
It has been documented that more than 17 million Americans experience a mild traumatic brain injury (mTBI) better known as a concussion on an annual basis. Around 15 percent suffer from consistent symptoms sometimes for more than three months.
Evaluating possible results and recovery time following a concussion can be quite difficult. Usually, physicians have to depend on patient response and cooperation in order to properly determine the seriousness of the injury.
"MRI and CT brain images of concussion patients are often normal. Diffusion tensor imaging is the first imaging technique that shows abnormalities associated with concussion, because it is able to see white matter tracts at a microscopic level," said assistant professor of neuroradiology at the University of Pittsburgh School of Medicine, Saeed Fakhran, M.D.
DTI is a highly developed form of MRI that enables researchers to examine and evaluate microscopic changes in the brain's white matter. The brain's white matter is comprised of millions of nerve fibers called axons that function like communication cables connecting different areas of the brain. DTI produces a measurement, called fractional anisotropy (FA), of the movement of water molecules along axons. In normal, healthy white matter, the direction of water movement is mostly homogeneous and measures high in FA. When water movement is more random, FA values is reduced. Unusually low FA is linked with cognitive impairment in patients with brain injuries.
The research team studied the medical records and imaging results of 69 patients diagnosed with mTBI between 2006 and 2013, including 47 males and 22 females, and 21 controls composed of 10 males and 11 females (average age of males: 17; average age of females: 16). Of the 47 males with mTBI, 32 (68 percent) were injured while playing a sport, as well as 10 of the 22 females (45 percent).
All patients received the same assessment, including a computerized neurocognitive test and DTI of the brain. The DTI scans of the mTBI patients showed irregularities within the uncinate fasciculi (UF), a white matter tract that connects the frontal and temporal lobes of the brain. Although its precise role is contentious, the UF tract is believed to allow temporal lobe-based memory associations to modify behavior though interactions with another area of the brain.
The DTI scans showed that compared to the female mTBI patients, the male mTBI patients had considerably decreased UF FA values.
"In the future, we would like to look at the issue of gender and concussions more in depth to determine who does better and why," said Fakhran.
A statistical analysis of the data showed that UF FA value was a better predictor of recovery time than initial symptom severity based on neurocognitive testing. The most significant risk factor for a recovery time longer than three months was decreased UF FA. Male gender also directly corresponded with increased recovery time.
"The potential of DTI and UF FA to predict outcome after concussion has great clinical impact. Currently, we are heavily reliant on patient reporting, and patients may have ulterior motives, such as wanting to get back to play. But you can't trick an MR scanner," said Fakhran.
The median time to symptom recovery for all concussion patients was 54 days. Yet, when compared to the female patients who recovered in a median of 26.3 days, recovery was considerably longer for the male patients (an average of 66.9 days), regardless of initial symptom severity.
"Male gender and UF FA values are independent risk factors for persistent post-concussion symptoms after three months and stronger predictors of time to recovery than initial symptom severity or neurocognitive test results," said Fakhran.
Fakhran also notes that the outcomes of the study provide a possible role for UF FA values in triaging concussion in patients in the future.
"There's prognostic value in DTI for both children participating in sports as well as for professional athletes. Lower FA values in the uncinate fasciculi could offer a metric for evaluating the severity of mild traumatic brain injuries and predicting clinical outcome. We're not at the point where DTI can provide individual prognoses yet, but that's the hope and goal," he said.
