PET/CT imaging may improve differentiation between PTSD and mild traumatic brain injury

Hybrid imaging with positron emission tomography and computed tomography (PET/CT) in the pituitary region of the brain is a promising tool for differentiating military veterans with post-traumatic stress disorder (PTSD) from those with mild traumatic brain injury (MTBI), according to a new study presented at the annual meeting of the Radiological Society of North America (RSNA).

The study findings lend support to the theory that many veterans diagnosed with PTSD may actually have hormonal irregularities due to pituitary gland damage from blast injury. The pituitary gland plays an important role in regulating many body processes, including stress response.

 “Most of the time, Veterans diagnosed with PTSD are given antidepressants, but we think that by finding the right diagnosis, and treating what may actually be a hormonal imbalance due to damage from a blast injury to the pituitary gland, resulting in MTBI, they might benefit and experience some relief,” said study lead author Thomas M. Malone, B.A., from the Department of Neurosurgery at Saint Louis University School of Medicine in Saint Louis.

According to the US Veteran’s Administration, the diagnosis of TBI and other comorbidities such as PTSD, presents unique challenges for diagnosticians. The current VA screening tool is intended to initiate the evaluation process and is not used to make a diagnosis, so patients are diagnosed after an interview by a skilled clinician.

However, it is reported that patients who have experienced MTBI under chaotic circumstances such as combat and may be unaware of the injury, or ignore any brief loss of consciousness that may have occurred from a blast. The patient may present some time after the original injury and details surrounding the injury may be unclear.

According to the press release, the researchers focused on 18F-fluorodeoxyglucose (18F-FDG) PET/CT, which provides a picture of metabolism by measuring uptake of the radiopharmaceutical FDG. A review of 159 brain 18F-FDG PET/CT exam records showed that FDG uptake in the hypothalamus was significantly lower in the MTBI-only group compared with normal controls. FDG uptake in the pituitary gland was significantly higher in the MTBI and PTSD group compared with the MTBI-only group.

The finding of higher FDG uptake in the pituitary glands of PTSD sufferers supports the theory that many veterans diagnosed with PTSD may actually have hypopituitarism, a condition in which the pituitary gland does not produce normal amounts of one or more of its hormones.

"This raises the possibility that some PTSD cases are actually hypopituitarism masking itself as PTSD," Malone said. "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."

The results suggest that PET/CT may provide an effective way to diagnose and differentiate PTSD from MTBI and offer more insight into the biological manifestations of the disorder.