A new MR imaging technique is giving experts more insight into COVID’s impact on the brain.
The technique is known as correlated diffusion imaging (CDI). CDI mixes MRI signals at different gradient pulse strengths and timings, which results in better visualization of differences in the way water molecules move through tissues.
The technique was developed at the University of Waterloo by systems design engineering professor Alexander Wong, PhD. He initially invented the technique to improve the detection of cancer on imaging, but when scientists at the Rotman Research Institute in Toronto, Canada, got wind of the technique, they decided to compare its utility to others in a cohort of COVID patients.
Researchers recruited a group of infected patients to undergo MR imaging using three different techniques—diffusion-tensor imaging, diffusion-tensor decomposition of orthogonal moments and the newly developed CDI technique. The self-isolated patients completed brain imaging while still testing positive for the respiratory virus and then again three months later to assess for any lingering abnormalities. The same was done in a control group of COVID-negative patients.
Wong’s CDI technique proved to be the most sensitive and was the only method to demonstrate COVID-related brain effects, according to the study, which was published in Human Brain Mapping.
Using CDI, researchers noted differences in two regions of the brain—the frontal lobe and the cerebellum. In patients with COVID, less restricted diffusion of water molecules was observed in their frontal lobe white matter. Conversely, diffusion was more restricted in cerebellar white matter of COVID patients.
“Some may think COVID-19 affects just the lungs,” Wong said. “What was found is that this new MRI technique that we created is very good at identifying changes to the brain due to COVID-19. COVID-19 changes the white matter in the brain.”
The study was centered on identifying changes, rather than damage. But there is the possibility that those changes could lead to damage or disease, authors of the Rotman study noted.
In the future, the new imaging technique could be used to assess for damage in the brains of COVID patients, in addition to having utility in other scenarios, Wong suggested.
“Hopefully, this research can lead to better diagnoses and treatments for COVID-19 patients,” Wong said. “And that could just be the beginning for CDI as it might be used to understand degenerative processes in other diseases such as Alzheimer’s or to detect breast or prostate cancers.”
In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She joined Innovate Healthcare in 2021 and has since put her unique expertise to use in her editorial role with Health Imaging.