Metabolic activity in the pituitary gland may help doctors differentiate between patients who are exhibiting signs of mild traumatic brain injury alone and those who are also suffering from post traumatic stress disorder (PTSD), researchers suggested here.

Metabolic activity in the pituitary gland — as measured by PET/CT scans — was significantly higher in the mild traumatic brain injury plus PTSD patient group who averaged an SUVmean (standardized uptake value) score of 3.08, compared with a score of 2.54 for patients whose condition was limited to mild traumatic brain injury (P=0.0418).

“If a person has signs and symptoms of PTSD with mild traumatic brain injury that persist for many months, a physician might consider starting hormonal therapy for these patients,” study co-author Thomas Malone, BA, a research associate at Saint Louis University Hospital, in Missouri, told MedPage Today.

“We retrospectively reviewed 159 dedicated brain PET/CT studies,” Malone explained while presenting his study at a press c0nference at the centennial meeting of the Radiological Society of North America. “All the patients in our study had traumatic brain injuries.”

He said that researchers acquired the images in the morning and did so according to standard brain PET/CT protocol. They subsequently performed MRI scans of the brain, which were interpreted as structurally normal for all subjects by a fellowship-trained neuroradiologist. Patients with traumatic brain injury were further stratified by severity based on criteria from the Department of Defense and Veterans Affairs Consensus Definition.

PET/CT scans were read by two board-certified nuclear medicine physicians blinded to the groups, and a log recorded the SUVmax and SUVmean of the pituitary gland and the hypothalamus.

The SUVmax from the hypothalamus was significantly lower in traumatic brain injury-only patients compared with the normal controls (5.78 versus 6.46, P=0.038).

Osama Raslan, MD, MBCh, nuclear medicine resident at Saint Louis University Hospital and the lead author of the study, noted, “To our knowledge this is the first imaging study that supports other research suggesting that pituitary dysfunction may contribute to PTSD symptoms in patients with mild traumatic brain injury.”

Malone said that because of the pituitary’s location in the brain it can be subject to damage in blast-related trauma — a frequent cause of injuries in combat areas in the Middle East and elsewhere. “Research suggests that persistent self-reported neurocognitive difficulties and brain dysfunction may be related to microstructural damage that remains invisible using standard magnetic resonance imaging or computer-assisted tomography (CT) scans,” he said.

The researchers cited Department of Defense statistics that indicates 152,986 cases of PTSD between 2000 and 2014.

Previous research examining blood work suggests that hormonal abnormalities may account for PTSD symptoms in blast-related mild traumatic brain injury, Malone said.

“SUVmean in the pituitary region is a promising objective tool for differentiating mild traumatic brain injury plus PTSD patients from mild traumatic brain injury-only patients in a post-acute veteran population,” Malone said. “PTSD represents an increasing public health issue that is difficult to diagnose. PET/CT activity in pituitary/hypothalamus may provide an objective method to diagnose and differentiate PTSD.”

Press conference moderator Max Wintermark, MD, chief of neuroradiology at Stanford University Medical Center in Stanford, Calif., told MedPage Today that the studies described by Raslan and Malone are preliminary work. “I think we need more research in this area. Mild traumatic brain injury is a heterogeneous disease. PTSD is also a heterogeneous disease.”

“Here we have very interesting results but we have a very small sample size,” he continued. Wintermark said the differences in the SUVmax and SUVmean as described by the authors was not compelling at this time “for clinicians to apply that to individual patients because of the variability of the measure. I don’t think we are ready to use that tool in the clinic at this time in traumatic brain injury or PTSD patients.”

He suggested that doing hormone screening in every PTSD patient might not be a good use of resources.