Research into the long-term effects of Covid-19 has found lung abnormalities three months after patients became infected with the virus.
The small-scale study used hyperpolarised xenon gas during MRI scans to create images of lung damage.
The gas was inhaled by patients, which allowed researchers to see areas where air is not flowing easily into the blood. This damage to lungs from Covid-19 was not visible on a standard MRI or CT scan.
All the patients had persistent shortness of breath and tiredness three months after being ill with coronavirus, even though none had been admitted to intensive care or required ventilation. Conventional scans found no issues with their lungs.
The reduction in lung function detected in the study might be an explanation for some patients experiencing persistent symptoms even with seemingly ‘normal’ results from standard GP and hospital tests, said the researchers.
So far only seven patients have taken part in the study. They were aged between 19 and 69.
An initial group of 40 patients in Sheffield and Oxford will take part 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, head of imaging and NIHR research professor of Magnetic Resonance Physics at the University of Sheffield, said: “Hyperpolarised xenon MRI offers a unique means of imaging impairment to oxygen uptake in the lungs caused by Covid-19 infection and its after effects.
“In other fibrotic lung diseases we have shown the methods to be very sensitive to this impairment and we hope the work can help understand Covid-19 lung disease.”
Professor Fergus Gleeson, consultant radiologist at Oxford University Hospitals NHS Foundation Trust and the University of Oxford’s head of academic radiology, said: “We may be getting an insight into why some patients have symptoms long after they have left hospital, and when other tests are normal. This may help us identify patients that may potentially benefit from treatment even after discharge, for example with steroids or other therapies.”
A separate study has found signs of damage to multiple organs have been detected in young and previously healthy people four months after they were infected by Covid-19.