A new study published in Radiology challenges the notion that "invisible" brain injuries are harmless, particularly in military members with a history of repetitive blast exposure. Researchers found that even when standard MRI exams appeared normal, advanced MRI techniques revealed clear abnormalities in the brains of service members with more blast exposure.

The study, which included 212 service members from Special Operations Forces, showed that higher blast exposure correlated with changes in the functional connectivity between brain regions. These changes were associated with more severe symptoms such as memory problems, emotional difficulties, and signs of post-traumatic stress disorder. The researchers noted that repeated trauma seemed to weaken the brain's internal communication.

Dr. Andrea Diociasi, the lead author of the study and a neuroradiologist at Massachusetts General Hospital and Harvard Medical School, explained that the findings highlight the need to rethink how we view 'mild' brain injuries. "We're validating and expanding on prior work using a much larger and very specific population—Special Operations Forces—while also showing that these issues likely extend beyond the military," Dr. Diociasi said.

The research team used advanced MRI techniques to analyze structural and resting-state functional MRI data of Special Operations Forces members. They found that even though these service members' brains looked normal on traditional exams, they had noticeable differences in brain activity and structure when examined using advanced MRI. The study also revealed that certain brain regions were actually larger in more-exposed individuals, which could reflect long-term tissue changes like scarring.

Dr. Diociasi emphasized that these findings have broader implications for society. "We need to rethink how we view 'mild' brain injuries not just in soldiers but across society," he said. "The findings reveal that even when the brain looks 'normal,' it might still be carrying hidden signs of trauma—and we now have tools to detect them."

The study challenges the idea that "invisible" injuries are harmless and underscores the importance of early detection and better treatment for these types of injuries. Dr. Diociasi noted that with their multimodal approach, they tried to connect the dots but acknowledged that many gaps still need to be filled.

For more information on this study and other related topics, visit RSNA News or access the Radiology study titled "Distinct Functional MRI Connectivity Patterns and Cortical Volume Variations Associated with Repetitive Blast Exposure in Special Operations Forces Members."