Cause of long-COVID symptoms revealed by lung-imaging research at Western University

Treating symptoms such as breathlessness, fatigue and brain fog in those who suffer from long-COVID is now possible thanks to research led by Western University.

Using a functional MRI where patients inhale xenon gas, researchers can see in real-time what it is happening inside the lungs. Preliminary results show symptoms are related to microscopic abnormalities that affect how oxygen is exchanged from the lungs to red blood cells. The research was published Tuesday in Radiology.

Having participants inhale the gas while being scanned by the MRI allowed researchers to see how the 500 million air sacs in the lungs deliver oxygen to the blood. In the case of long-COVID patients, the transition of the oxygen was depressed compared to healthy volunteers.

"They had all been about nine months post-infection, and we wondered if we could find the source of their symptoms because they were all highly symptomatic and their quality of life scores were really very poor," said Grace Parraga, a professor and the Tier 1 Canada Research Chair in Lung Imaging to Transform Outcomes at Western's Schulich School of Medicine & Dentistry.

"What we see in patients who have long-COVID, and they're symptomatic, is that they actually have normal pulmonary function. So their breathing tests that doctors would prescribe were normal, and their CT scans were normal. But the MRI told us a completely different story."

The research also shows that there doesn't seem to be a difference in the severity of the abnormality between patients who required hospitalization for COVID-19 and those who recovered from the illness at home.

"Now that we have the what's happening, where it's happening and when it's happening, we can figure out the why and the who," said Parraga. "All the data that we acquired in these individual patients we gave to them, and we also gave to their collaborators at [the hospital] ... and that really armed those physicians with new information so that they could make treatment decisions for these patients."

Patients were recruited from London Health Sciences Centre (LHSC) and St. Joseph's Health Care who had experienced ongoing shortness of breath for more than six weeks post-infection.

Among those who participated in the study include Alex Kopacz, a London Olympian who was hospitalized with the virus in 2021.

"I was on oxygen for almost two months after COVID, and it took me almost three months to get to a place where I could go for a walk without gasping for air," said Kopacz in a statement.

"The take-home message for me is that we have to remember that this virus can have very serious long-term consequences, which are not trivial. In my case, prior to getting sick, I didn't think it would really affect me."

Researchers are now working on a one-year follow-up to better understand the results of the study.

The $1-million study included five centres across Ontario, including LHSC, St. Joseph's Health Care, Lakehead University, McMaster University, Toronto Metropolitan University and Sick Kids Hospital in Toronto.