Neuron damage in explosion-related ‘mild’ traumatic brain injuries can be more extensive than previously thought and is not necessarily related to the severity of clinical symptoms, researchers said.

Among 63 U.S. soldiers evacuated from Iraq or Afghanistan and diagnosed clinically with blast-related mild traumatic brain injury, diffusion tensor imaging (DTI) revealed significant damage to neuronal axons that was not evident on CT or conventional MRI scans, according to David L. Brody, MD, PhD, of Washington University in St. Louis, and colleagues.

Statistical analysis of the DTI scans showed that abnormalities were significantly more common in the middle cerebellar peduncles, cingulum bundles, and right orbitofrontal white matter in these soldiers than in 21 others with blast exposure but no diagnosis of brain injury.

Yet only 18 of the 63 brain-injured soldiers had definitively abnormal findings from the DTI scans when analyzed individually, suggesting that the extent of axonal damage did not correlate strongly with clinical symptoms.

‘Traumatic brain injury remains a clinical diagnosis,’ Brody and colleagues wrote in the June 2 issue of the New England Journal of Medicine.

However, they also argued that DTI could be included in triage and treatment planning if clinical utility is eventually established, because it is easy to perform with […]