29/10/2026
🫁 Some people with long COVID feel breathless for months, even when their lung scans look normal. A special MRI scan revealed hidden problems in how their lungs move oxygen into the blood.
Breathlessness is one of the most common long COVID symptoms. But standard tests, like CT scans, often show nothing wrong.
Researchers at the University of Oxford and the University of Sheffield in the UK used a different type of scan.
Patients breathed in xenon, a harmless gas, while having an MRI. The gas behaves much like oxygen, so the scan can show how well it passes from the lungs into the blood.
The study included 11 people with long COVID who had not been hospitalized, scanned 8 to 11 months after infection.
It also included 12 people who had been hospitalized with COVID, and a group of healthy volunteers. All the patients felt breathless.
Their CT scans were normal or nearly normal.
But the xenon scans showed that gas did not pass from the lungs into the blood as well as in healthy people. This was seen in both patient groups.
The problem was larger in the long COVID patients who had never been hospitalized.
"These abnormalities are not apparent on conventional imaging," said senior researcher Fergus Gleeson.
The researchers think the issue may lie in the lining of the air sacs or in the tiny blood vessels around them.
This matters because it may help explain why some people feel breathless when other tests look normal.
There are big caveats. The study was very small, with only 23 patients.
It does not prove the lung changes cause breathlessness, or show whether they get better over time.
The team said larger studies were needed. The xenon scan is also only available in a few specialist centers.
📃 RESEARCH PAPER
📌 James T. Grist et al., "Lung Abnormalities Depicted with Hyperpolarized Xenon MRI in Patients with Long COVID," Radiology.