New research could help pinpoint which patients are most at risk of dying from a type of aneurysm.

Scientists have developed a technique that could be used to diagnose the severity of aortic aneurysms, which are balloon-like swellings in the aorta – the body’s main artery.

If left untreated they can rupture, causing massive internal bleeding and sudden death.

Researchers have found that the more immune cells that are in the aneurysm, the faster it can grow and the more unstable it is likely to be, making it more likely to rupture soon.

For the study, published in the journal Circulation: Cardiovascular Imaging, they used a powerful magnetic resonance imaging scanner to examine immune cell activity in a group of patients with aneurysms in their aorta. They injected tiny particles of magnetic iron into the patients’ bloodstream – on the scan this glows red and orange in areas of the aneurysms where immune cells are gathering.

The scientists, based at the University of Edinburgh, found three distinct types of abdominal aortic aneurysm, all with different appearances in the scan.