Hybrid neuroimaging of the pituitary region of the brain could help distinguish military veterans with posttraumatic stress disorder from those with mild traumatic brain injury, according to research presented at the annual meeting of the Radiological Society of North America.

Besides the utility of PET/CT in differential diagnosis, the findings support the notion that pituitary gland damage from blast injuries are causing hormonal irregularities affecting veterans diagnosed with posttraumatic stress disorder(PTSD).

“It’s important that providers as well as patients are aware of what might be causing these PTSD-like symptoms and that there are therapeutics that can help them if current therapies, such as antidepressants, anxiolytics and group therapy, aren’t helping,” Thomas M. Malone, a research associate at Saint Louis University School of Medicine, told Endocrine Today.

Malone and colleagues focused on 18F-fluorodeoxyglucose (18F-FDG) PET/CT, which measures uptake of the radiopharmaceutical FDG to show metabolism, in a retrospective review of 159 brain exam records; all PET images were obtained in the morning and adhered to standard brain PET/CT protocol. MRI scans of the brain were subsequently taken and given a structurally normal interpretation by a fellowship-trained neuroradiologist.

Cases were divided into three groups — normal control, traumatic brain injury(TBI) and TBI+PTSD — matched for age and sex. Based on criteria from the 2009 Department of Defense and Department of Veterans Affairs consensus definition of TBI, patients were further stratified by severity.

Two board certified nuclear medicine physicians masked to the groups read the PET/CT scans.

Maximum standardized uptake value (SUVmax) and mean standardized uptake value (SUVmean) of the pituitary gland and the hypothalamus were log-recorded. With approximately normal distributions and sufficiently large sample sizes, parametric tests were performed.

The SUVmax from the hypothalamus was lower in patients with TBI only vs. normal controls (5.78 vs. 6.46; P=.04). With TBI stratified by severity and limited to military veterans, the SUVmean from the pituitary was higher among patients with mild TBI+PTSD compared with those with mild TBI only (3.08 vs. 2.54; P=.04).

The higher FDG uptake demonstrated in the pituitary glands of patients with PTSD points to the possibility that some PTSD cases may actually be hypopituitarism masked, according to the researchers, in which case screening and treatment could help.

“I really hope it helps remove the stigma that many soldiers feel is attached to a PTSD diagnosis,” Malone said. “Being able to see that there is a physical, neurological injury caused by blast or a car accident should help remove any moral judgment about someone feeling depressed, anxious or continuing to experience fatigue or cognitive difficulties after a [TBI].” – by Allegra Tiver