Some Covid patients still show lung damage as long as nine months after leaving hospital, a new study has confirmed.
Scientists used state-of-the-art equipment to reveal damage not picked up by regular CT scans or examination.
The disease causes lung abnormalities which prevent oxygen reaching the bloodstream - causing breathlessness, according to new research.
Many people experience some symptoms for a long period of time after infection - a condition dubbed ‘Long Covid’.
Findings could pave way for new treatments
New cutting-edge hyperpolarised xenon MRI (XeMRI) scans used by researchers at the University of Sheffield and Oxford University has now found signs of lung damage at least three months after patients left hospital.
The team behind the findings think the abnormalities they discovered could explain breathlessness experienced by patients who have never been hospitalised.
They now hope the discovery will help in the development of treatments for Long Covid and lung damage.
Prof Fergus Gleeson, Professor of Radiology at Oxford University, said: “Many Covid-19 patients are still experiencing breathlessness several months after being discharged from hospital, despite their CT scans indicating that their lungs are functioning normally.
“Our follow-up scans using hyperpolarised xenon MRI have found that abnormalities not normally visible on regular scans are indeed present, and these abnormalities are preventing oxygen getting into the bloodstream as it should in all parts of the lungs.”
The new scan involves a gas - 129xe - which is inhaled and allows higher resolution images not possible with standard MRI or CT scans.
The technique was developed by Pulmonary, Lung and Respiratory Imagining Sheffield (POLARIS) research group led by Prof Jim Wild at the University of Sheffield.
He and his team performed the first clinical research studies in the UK and the world’s first clinical diagnostic scanning with the technology.
In this study, the team found 129Xe MRI can pinpoint the parts of the lung where oxygen uptake is impaired because of long standing effects, even though they often look normal on CT scans.
A precedent for multi-centre research
Prof Gleeson added: “Although we are currently only talking about early findings, the XeMRI scans of non-hospitalised patients who are breathless - and 70 per cent of our local patients with Long COVID do experience breathlessness - may have similar abnormalities in their lungs.
“We need a larger study to identify how common this is and how long it will take to get better.
“We have some way to go before fully comprehending the nature of the lung impairment that follows a COVID-19 infection.
“But these findings, which are the product of a clinical-academic collaboration between Oxford and Sheffield, are an important step on the path to understanding the biological basis of long COVID and that in turn will help us to develop more effective therapies.”
Professor Jim Wild Head of Imaging at the University of Sheffield, said: “The findings of the study are very interesting.
“It is great to see the imaging technology we have developed rolled out in other clinical centres, working with our collaborators in Oxford on such a timely and clinically important study sets a real precedent for multi-centre research and NHS diagnostic scanning with 129Xe MRI in the UK.”
The findings have been published in the journal Radiology.