Doctors often use a test called right heart catheterization to check how serious a person’s heart failure is. Heart failure affects hundreds of thousands of people in the UK. The team developed a method using something called T2 mapping, a regular part of many heart MRI scans. Then they studied 628 more people who had recently been diagnosed with heart failure. Even when taking age, other illnesses, and overall heart function into account, the new MRI method still worked well.