MRI Technique Could Help Diagnose CTE

A specialized MRI test could help clinicians finally recognize chronic traumatic encephalopathy (CTE) in living patients.

A team, led by Ronel Veksler, Departments of Physiology and Cell Biology, Brain and Cognitive Sciences, The Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, showed the effectiveness of a modified dynamic contrast-enhanced MRI approach to detect impairments in brain microvascular function.

CTE is a neurodegenerative disorder that currently can only be diagnoses through a brain tissue analysis following death.

In the past, research suggests a pathogenic role for the microvascular injury, specifically blood-brain barrier dysfunction and breaching the integrity of the blood-brain barrier (BBB) causes many different brain disease and neurodegeneration as a result of aging.

In the study, the investigators scanned 42 adult male amateur football players, as well as a control group with 27 athletes practicing a non-contact sport and 26 non-athletes.

The investigators also performed MRI scans on 51 individuals with brain pathologies involving the blood-brain barrier, mostly malignant brain tumors, ischemic stroke, and hemorrhagic traumatic contusion.

The team also used National Football League sideline concussion assessment tools to document previous head injuries, including concussions, as well as symptoms assessment and the Standardized Assessment of Concussion (SAC) tests.

Using the data from the prolonged scans, the investigators generated maps that visualize the permeability value for each brain voxel.

“Our permeability maps revealed an increase in slow blood-to-brain transport in a subset of amateur American football players, but not in sex- and age-matched controls,” the authors wrote. “The increase in permeability was region specific (white matter, midbrain peduncles, red nucleus, temporal cortex) and correlated with changes in white matter, which were confirmed by diffusion tensor imaging.”

Football players (27.4%) were about 3 times more likely to display a leaky blood-brain barrier than the control group, with individual variability explaining the wide range of cognitive deficits and neuropsychiatric impairments observed in players.

The investigators also found increased permeability persisted for month, which was found in players who scanned both during the season and in the offseason.

Further examination of patients with brain pathologies showed slow tracer accumulation characterizes areas surrounding the core of injury, which frequently shows fast blood-to-brain transport.

Overall, the findings suggest a dynamic contrast-enhanced-MRI can help diagnose specific microvascular pathology following a traumatic brain injury and other brain pathologies.

"Since a leaky BBB is also found in CTE and causes brain dysfunction and degeneration, it now seems that this test could provide the first (and so far the only) evidence for brain injury in the players we studied on the Israel football team," Alon Friedman, MD, a neurosurgeon and researcher at BGU and Dalhousie University in Canada, said in a statement.

"Importantly, we believe that those with persistent leak encompassing months or years are more likely to develop CTE. Many players seem to repair their BBB quickly, and if they do not suffer from repeated TBIs [traumatic brain injuries] or are not sensitive to brain injury, they are not likely to develop CTE."

The researchers would like to conduct future studies to determine the prevalence and spatial-temporal characteristics of brain-blood barrier disorders in football players without clinical signs and symptoms of CTE.

The study, “Slow blood-to-brain transport underlies enduring barrier dysfunction in American football players,” was published online in Brain.