Motion-compatible brain scanner removes the need to lie still

West Virginia University (WVU) neuroscientists, physicists and engineers have developed an upright neuroimaging device that allows patients to move around while undergoing a brain scan.

Described in the journal Communications Medicine, the team’s prototype was designed to address issues with traditional positron emission tomography (PET) scanners, which require patients to lie still for imaging.

“A lot of PET imaging is being done for research or diagnostics with patients with diseases that cause involuntary or uncontrollable movement, such as Parkinson’s,” said Julie Brefczynski-Lewis, a research assistant professor at the WVU School of Medicine and the Rockefeller Neuroscience Institute. “This makes it difficult or impossible to test these patients when their symptoms become too severe, since regular brain imagers require staying very still.”

Furthermore, traditional imaging tools can be difficult for studying human behaviours and activities with natural movement such as gestures, conversation and balance. Brefczynski-Lewis noted, “In order to study balance, people have been in MRIs lying down and imagining themselves balancing, which isn’t the same as actually balancing, or they have a surface imager that doesn’t capture the deep brain structures. You can see some parts of the brain, but not the deep core parts of the brain that are usually more involved with things like movement, balance, emotion, memory, fear and joy.”

Brefczynski-Lewis and her team developed a motion-compatible brain scanner with funding from West Virginia Clinical and Translational Science Institute, which they have now upgraded to a new and improved version. While both versions are helmets, the first was heavier and only allowed slight movement of the head from side to side. The new one, called an Ambulatory Motion-enabling PET (AMPET), is lighter weight and fits the head much like hard hats construction workers wear. A balanced support is at the top.

“What we like about the AMPET is that it moves with the head, and you can be in a real environment where you’re immersed and walk with it on,” Brefczynski-Lewis said. “What we demonstrated in the study is that when the patients walk, it’s not moving relative to the head and that’s what allowed us to get a relatively clean image. We also wanted to see what should be improved by us or other laboratories that are making these devices.”

To test their new prototype, the team enlisted volunteer outpatients who were scheduled for other scans and were already receiving medications used for imaging. Participants fitted with the helmet walked in place while the researchers watched for motion tolerance and assessed neural activity in motor-related brain regions.

“We observed brain activity in the parts of the brain that control leg movements when the patients walked, which was what we had hoped to see,” Brefczynski-Lewis said. Their findings were further confirmed by observing one patient who had a prosthetic leg from hip to foot, whose brain activity displayed predominantly in the area that represented the natural leg.

“That was almost a separate test in itself that we didn’t expect.”

To enhance the prototype, the researchers want to add a motion tracking system as well as make the helmet bigger so that it could image a larger area of the brain. Brefczynski-Lewis stated, “Motion tracking is already made for other technologies, so all we have to do is apply it to our device. That will help because sometimes we miss the area of the brain we want to see.”

In the future, the team envision the AMPET being used to monitor brain activity and provide treatment for people with PTSD, study mindfulness meditation, and integrate with virtual reality technologies. Brefczynski-Lewis noted, “If you want to study human behaviours like walking, anxiety-provoking tasks or even addiction, this device could provide a way to image.

“It’s also helpful with imaging for patients with cognitive issues like dementia because they have trouble staying still and even understanding the instruction they need to stay still, so they usually have to be anaesthetised. If we want to image their brain while they’re awake and alert, this would be a way to do that as well.”

Image caption: Julie Brefczynski-Lewis, along with students Colson Glover and Nanda K Siva, conducts a walking PET scan demonstration at WVU Health Sciences. Image credit: WVU/Davidson Chan.