HypErpolarised Xenon Magnetic Resonance PuLmonary Imaging in PAtIeNts with Long-COVID (EXPLAIN)

We wish to understand why some Long-COVID sufferers struggle with breathlessness on exertion and have a reduced ability to exercise. To do this, we will use MRI scanning and a special gas (hyperpolarised xenon) which is breathed in during the scan. The xenon gas is harmless in the quantity we use. This technique shows the movement of xenon within the lungs and moving out of the lungs into the bloodstream, similar to how oxygen is absorbed. The scans take about 15 minutes. In patients hospitalised with COVID-19, we found that scans several months after discharge showed evidence of persisting lung damage, even when other tests were normal. Importantly, on follow-up scanning, some have remained abnormal. We will use the same scan technique in Long-COVID sufferers not admitted to hospital, who have ongoing breathlessness on exertion to see if they have lung damage. If lung abnormalities are found, we will assess their severity and whether they improve over time. To do this, we will compare scans in the different groups of participants enabling us to see if their breathing problems are related to the lung damage. We will also include an MRI scan of the heart in some of the trial participants to see if the heart has also been damaged. If the Xenon MRI scans separate patients with and without lung disease, we will then analyse the CT scans using artificial intelligence and the blood samples to see if we can find associated abnormalities. We aim to provide a much-needed explanation to sufferers of Long-COVID struggling with breathlessness. Learning more about the nature of damage within the lungs through xenon MRI may help with the future development of treatments, and provide a reliable way of measuring lung damage changes over time.