(Image caption: Uncinate fasiculus, an important tract with the greatest concentration of progesterone receptors, show greater injury in males than females after mild traumatic brain injury (mTBI). (a) Axial and (b) coronal images show regions of decreased fractional anisotropy in male patients with mTBI relative to female mTBI patients, involving the uncinate fasiculus (red) bilaterally.)

Gender May Contribute to Recovery Time After Concussion

A study of concussion patients using diffusion tensor imaging (DTI) found that males took longer to recover after concussion than females did. Results of the study, which show that DTI can be used as a bias-free way to predict concussion outcome, are published online in the journal Radiology.

Each year, more than 17 million Americans suffer a mild traumatic brain injury (mTBI), more commonly known as a concussion, of which approximately 15 percent suffer persistent symptoms beyond three months.

Assessing outcomes and recovery time after concussion can be very subjective. Typically, physicians must rely on patient cooperation to assess injury severity.

"MRI and CT brain images of concussion patients are often normal," said Saeed Fakhran, M.D., assistant professor of neuroradiology at the University of Pittsburgh School of Medicine. "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."

DTI is an advanced form of MRI that allows researchers to assess microscopic changes in the brain’s white matter. The brain’s white matter is composed of millions of nerve fibers called axons that act like communication cables connecting various regions of the brain. DTI produces a measurement, called fractional anisotropy (FA), of the movement of water molecules along axons. In healthy white matter, the direction of water movement is fairly uniform and measures high in FA. When water movement is more random, FA values decrease. Abnormally low FA is associated with cognitive impairment in patients with brain injuries.

The research team examined 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 consisting of 10 males and 11 females (median age of males: 17; median age of females: 16). Of the 47 males with mTBI, 32 (68 percent) were injured while playing a sport, as were 10 of the 22 females (45 percent).

All patients underwent the same evaluation, including a computerized neurocognitive test and DTI of the brain. The DTI scans of the mTBI patients revealed abnormalities within the uncinate fasciculi (UF), a white matter tract that connects the frontal and temporal lobes of the brain. Although its exact role is controversial, 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 revealed that compared to the female mTBI patients, the male mTBI patients had significantly 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," Dr. Fakhran said.

A statistical analysis of the data revealed that UF FA value was a stronger predictor of recovery time than initial symptom severity based on neurocognitive testing. The most substantial risk factor for a recovery time longer than three months was decreased UF FA. Male gender also directly correlated with increased recovery time.

"The potential of DTI and UF FA to predict outcome after concussion has great clinical impact," Dr. Fakhran said. "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."

The average time to symptom recovery for all concussion patients was 54 days. However, compared to the female patients who recovered in an average of 26.3 days, recovery was significantly longer for the male patients (an average of 66.9 days), irrespective 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," Dr. Fakhran said.

He said results of the study indicate a potential role for UF FA values in triaging concussion patients in the future.

"There’s prognostic value in DTI for both children participating in sports as well as for professional athletes," he said. "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."

Veterans’ Head Injury Examined

Roadside bombs and other blasts have made head injury the “signature wound” of the Iraq and Afghanistan conflicts. Most combat veterans recover from mild traumatic brain injury, also known as concussion, but a small minority experience significant and long-term side effects.

Now, researchers at Albert Einstein College of Medicine of Yeshiva University, in cooperation with Resurrecting Lives Foundation, are investigating the effect of repeated combat-related blast exposures on the brains of veterans with the goal of improving diagnostics and treatment.

Mild traumatic brain injury can cause problems with cognition, concentration, memory and emotional control as well as post-traumatic stress disorder (PTSD). Einstein scientists are using advanced MRI technology and psychological tests to investigate the structural and biological impact of repeated head injury on the brain and to assess how these injuries affect cognitive function.

"Right now, doctors diagnose concussion purely on the basis of someone’s symptoms," said Michael Lipton, M.D., Ph.D., associate director of Einstein’s Gruss Magnetic Resonance Research Center. "We hope that our research will lead to a more scientifically valid diagnostic technique—one that uses imaging to not only detect the underlying brain injury but reveal its severity. Such a technique could also objectively evaluate therapies aimed at healing the brain injuries responsible for concussions." Dr. Lipton is also associate professor of radiology, of psychiatry and behavioral sciences and of neuroscience at Einstein and medical director of MRI services at Montefiore Medical Center, the University Hospital for Einstein.

The Einstein researchers are studying 20 veterans from Ohio and Michigan who were deployed in Iraq and Afghanistan and have exhibited symptoms of repeated concussion. Twenty of the veterans’ siblings or cousins without concussion are acting as controls. The researchers are using an advanced MRI-based imaging technique called diffusion tensor imaging (DTI) to identify injured brain areas.

DTI “sees” the movement of water molecules within and along axons, the nerve fibers that constitute the brain’s white matter. This imaging technique allows researchers to measure the uniformity of water movement (called fractional anisotropy, or FA) throughout the brain. Abnormally low FA within white matter indicates axon damage and has previously been associated with cognitive impairment in patients with traumatic brain injury. (The researchers also use DTI in an ongoing study of amateur soccer players to assess possible brain injury from repeatedly heading soccer balls.)

The final group of veterans is scheduled to visit Einstein for testing in February 2014. Preliminary results should be available later this year.

Researchers Find Evidence That Brain Compensates After Traumatic Injury

Researchers at Albert Einstein College of Medicine of Yeshiva University and Montefiore Medical Center have found that a special magnetic resonance imaging (MRI) technique may be able to predict which patients who have experienced concussions will improve. The results, which were presented at the annual meeting of the Radiological Society of North America (RSNA), suggest that, in some patients, the brain may change to compensate for the damage caused by the injury.

“This finding could lead to strategies for preventing and repairing the damage that accompanies traumatic brain injury,” said Michael Lipton, M.D., Ph.D., who led the study and is associate director of the Gruss Magnetic Resonance Research Center at Einstein and medical director of MRI services at Montefiore, the University Hospital and academic medical center for Einstein.

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“In a traumatic brain injury, it’s not one specific area that is affected but multiple areas of the brain which are interconnected by axons,” said Dr. Lipton, who is also associate professor of radiology, of psychiatry and behavioral sciences, and in the Dominick P. Purpura Department of Neuroscience at Einstein. “Abnormally low FA within white matter has been correlated with cognitive impairment in concussion patients. We believe that high FA is evidence not of axonal injury, but of brain changes that are occurring in response to the trauma.”