Studies on the long-term effects of Covid-19 showed abnormalities in the lungs three months after patients were infected with the virus.
A small-scale study used hyperpolarised xenon gas during MRI scans to create images of lung injury.
The gas was inhaled by the patients, which allowed researchers to see areas where air does not flow easily into the blood. This Covid-19 lung injury was not seen on a standard MRI or CT scan.
All patients had persistent shortness of breath and fatigue three months after coronavirus disease, even though none had been admitted to intensive care or required ventilation. No lung problems were found in conventional scans.
The reduction in lung function found in the study could explain some patients experiencing persistent symptoms, even with seemingly “normal” results from standard medical and hospital tests, the researchers said.
So far, only seven patients have participated in the study. They were from 19 to 69 years old.
An initial group of 40 patients in Sheffield and Oxford will be involved in further studies over the next six months. The technique was developed by the University of Sheffield in collaboration with the University of Oxford.
Professor Jim Wild, director of imaging and professor of magnetic resonance physics at the University of Sheffield at NIHR, said: “Hyperpolarized xenon magnetic resonance offers a unique way to visualize the impairment of pulmonary oxygen uptake caused by Covid-19 infection and its sequelae.
“For other fibrotic pulmonary diseases, we have shown that these methods are very sensitive to this impairment, and we hope this work will help understand Covid-19 lung disease.”
Professor Fergus Gleeson, consultant radiologist at Oxford University Hospitals NHS Foundation Trust and head of academic radiology at the University of Oxford, said: “We may have some insight into why some patients have symptoms long after their discharge from hospital and when other tests are normal. This can help us identify patients who could potentially benefit from treatment even after discharge, for example with steroids or other treatments. ‘
A separate study showed signs of damage to multiple organs in young and previously healthy people four months after being infected with Covid-19.