Pituitary imaging may help distinguish PTSD from mild TBI in veterans

By Megan Brooks

NEW YORK (Reuters Health) - Metabolic abnormalities in the pituitary region of the brain seen on 18-FDG positron emission tomography-computed tomography (PET/CT) may help differentiate veterans with post-traumatic stress disorder (PTSD) from those with mild traumatic brain injury (mTBI).

Uptake of the radiotracer in the pituitary gland was significantly higher in veterans with blast-related mTBI and PTSD compared with those with mTBI only, researchers reported this week at the Radiological Society of North America (RSNA) annual meeting.

The findings support the hypothesis that many veterans diagnosed with PTSD may actually have hormonal irregularities due to pituitary gland damage from blast injury, they said.

"This study might impact treatment of veterans of PTSD by opening up the avenue of hormone replacement in addition to medications and therapies that they are currently receiving," study lead author Thomas M. Malone, from Saint Louis University School of Medicine, St. Louis, Missouri, said during a press briefing.

"Most of the time veterans just receive antidepressants and anxiolytics to treat anxiety and depression but we think by treating the underlying hormonal abnormalities they might gain benefit," Malone said.

Study presenter Dr. Osama A. Raslan noted that differentiating PTSD from mTBI can be difficult due to symptom overlap and, in many cases, normal structural neuroimaging results.

"Several studies have shown that there is hormonal dysfunction in patients with mTBI and PTSD. And this hormonal dysfunction is related to abnormality in the function of the hypothalamus and pituitary gland and that's why we opted to take a closer look at this area," he explained.

The researchers reviewed 159 brain FDG PET/CT studies in patients with mTBI only, those with mTBI and PTSD, and age- and gender-matched normal controls.

They found that FDG uptake in the hypothalamus was significantly lower in the mTBI-only group compared with normal controls.

Additionally, FDG uptake in the pituitary gland was significantly higher in the mTBI and PTSD group compared with the mTBI-only group.

This finding of higher pituitary FDG uptake in PTSD "raises the possibility that some PTSD cases are actually hypopituitarism masking itself as PTSD," Malone said in a conference statement.

"If that's the case, then we might be able to help those patients by screening for hormone irregularities and treating those irregularities on an individual basis," he said.

PET/CT imaging in the pituitary region is a "promising objective tool" for differentiating mTBI and PTSD from mTBI only in a post-acute veteran population, the researchers conclude in a meeting abstract.

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