Oxford University has found lung damage in COVID-19 patients using xenon gas in MRI scans.
These abnormalities would not be detectable in conventional scans, according to researchers.
However, by inhaling and holding a small amount of the gas for just a few seconds, the patient is able to create a much stronger MRI signal, providing doctors with multiple images of lung structure and function.
The study was conducted on ten people aged between 19 and 69, who had respiratory issues three months after falling ill with the virus.
They had shortness of breath and tiredness even though they had not been in intensive care while sick and traditional scans had not picked up problems in their lungs.
However, after using xenon gas, eight of them showed signs of lung damage.
The university is now planning a trial of up to 100 people to see if it is a common occurrence among former COVID-19 patients.
Shares in the US-based firm shot up 14% to 76.49p on Tuesday afternoon.