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Brain iron accumulated in people with acute post-traumatic headache, an imaging study showed.

Higher levels of iron based on T2* signal changes were seen in post-traumatic headache participants relative to healthy controls, according to Simona Nikolova, PhD, of the Mayo Clinic in Phoenix, and co-authors.

Positive correlations emerged between iron accumulation -- a marker of neural injury -- and headache frequency, time since mild traumatic brain injury, and the number of lifetime mild traumatic brain injuries, the researchers said in an abstract released ahead of the American Academy of Neurology (AAN) annual meeting.

Headache is a common complaint after traumatic brain injury. The most common phenotypes are migraine-like headache and tension-type-like headache.

In more than half of people with acute post-traumatic headache, head pain resolves naturally over time. Clinicians cannot predict which patients with acute post-traumatic headache will have pain that resolves, however, and which will have persistent head pain.

"These results suggest that iron accumulation in the brain can be used as a biomarker for concussion and post-traumatic headache, which could potentially help us understand the underlying processes that occur with these conditions," Nikolova said.

The researchers assessed 60 people who had post-traumatic headache due to mild traumatic brain injury and 60 age-matched healthy controls. All participants had 3T brain MRI with T2* mapping. T2* differences were determined using age-matched paired t-tests.

In the post-traumatic headache group, most mild traumatic brain injuries were due to a fall (45%), motor vehicle accident (30%), or a fight (12%). Other causes included hitting the head against an object or sports injuries. Overall, 46% had one mild traumatic brain injury in their lifetime, 17% had two, 16% had three, 5% had four, and 16% had five or more.

In post-traumatic headache participants, lower T2* values were seen in the right supramarginal area, left occipital, bilateral precuneus, right cuneus, right cerebellum, right temporal, bilateral caudate, genu of the corpus callosum, right anterior cingulate cortex, and right rolandic operculum (P<0.001).

Positive correlations emerged between lifetime mild traumatic brain injuries and iron accumulation in the right gyrus rectus and right putamen, the researchers said. Likewise, a relationship was seen between the time since the most recent mild traumatic brain injury and T2* signals in the bilateral temporal, right hippocampus, posterior and superior corona radiata, bilateral thalamus, right precuneus and cuneus, right lingual, and right cerebellum.

Headache frequency also was tied to T2* signals in the posterior corona radiata, bilateral temporal, right frontal, bilateral supplemental motor area, left fusiform, right hippocampus, sagittal striatum, and left cerebellum.

"Previous studies have shown that iron accumulation can affect how areas of the brain interact with each other," Nikolova said. "This research may help us better understand how the brain responds and recovers from concussion."

Because the study used an indirect measure of iron burden, it's possible the findings may be influenced by other factors like hemorrhage or changes in tissue water rather than iron accumulation, she noted.

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