Abnormalities in the lungs of long-Covid patients have been identified that may suggest unseen damage is the cause of ongoing breathlessness.
A pilot study by a collection of researchers from Sheffield, Oxford, Manchester and Cardiff used xenon gas and MRI scans to detect the abnormalities that would otherwise be missed by typical scans such as X-rays.
Breathlessness is a common symptom in the majority of long-Covid patients – those who continue to report symptoms of Covid-19 four weeks or more after initial infection – but the exact cause has so far been unclear.
The technique was developed by the Pulmonary, Lung and Respiratory Imaging Sheffield research group (POLARIS) at the University of Sheffield led by Professor Jim Wild.
Professor Wild said: “Xenon MRI is uniquely placed to help understand why breathlessness persists in some patients post Covid.
“Xenon follows the pathways of oxygen when it is taken up by the lungs and can tell us where the abnormality lies between the airways, gas exchange membranes, and capillaries in the lungs.”
Tests to determine lung function were conducted on 11 people with long-Covid and who had reported breathlessness, 12 people who had been admitted to hospital with Covid but did not have long-Covid, and 13 healthy people used as ‘controls’.
Each group inhaled xenon gas during an MRI scan. The gas was traced during the scans visualising how it moved from the lungs to the bloodstream, showing researchers less efficient gas transfer in the majority of the long-Covid sufferers tested when compared to the healthy controls.
This builds on an earlier study where the same technique was used on a smaller group of patients and found the same results.
The chief investigator for the new study, Professor Fergus Glesson of the University of Oxford, said: “There are now important questions to answer, such as how many patients with long-Covid will have abnormal scans, the significance of the abnormality we have detected, the cause of the abnormality, and its longer-term consequences.
“Once we understand the mechanisms driving these symptoms, we will be better placed to develop more effective treatments.”
The study is in pre-print and has yet to be formally peer reviewed.