Imaging the Effects of PTSD

 “We’re looking ahead to try to understand why exactly it is that people with PTSD have a higher risk of dementia,” Neylan said. “One reason is that it might be related to increased risk of cerebral vascular disease, or it might be related to an Alzheimer’s-like pathology, which involves increased deposition of amyloid.”

The SFVAMC is currently working with DoD to create a study looking at TBI and at amyloid depositions in the brain, as well as doing lumbar punctures to look for tau protein — another marker for dementia. They will also be using MRI to detect cerebral vascular disease.

“This will allow investigators to separate the effects of vascular disease and amyloid, and also determine if there are interactions between these two processes,” explained Mike Weiner, MD, head of SFVAMC’s Center for Imaging of Neurodegenerative Disease.

This kind of study would not have been possible even a few years ago. A PET ligand to help image amyloid has been available for years, but the development of newer ligands — a molecule that binds to specific other molecules — has made it feasible to run studies in a larger number of centers. Also, the magnets used in MRI scans have grown more powerful.

“We’ve been lucky to have some of the best technology in that field. We have a four-Tesla magnet and will be receive a 7-Tesla magnet in the next year,” Neylan said. “Higher field-strength magnets produce better special resolution for structural imaging and more fine-grained analysis of white-matter tracts. Now we’re able to look at brain profusion in a way that you used to only be able to do using PET scans.”

“It’s all very preliminary, but now able to see things that we haven’t been able to see before,” Neylan said. “And we’re still trying to make sense of what we’re seeing.”

There is still room for improvement. Researchers would prefer to image tau protein, Weiner said, rather than detect it through lumbar punctures. “We would also love to be able to image ‘neuronal density,’ since neurodegeneration itself is currently difficult to quantify in living subjects,” he said.