Adding a blood test alongside a brain scan could help pinpoint the cause of one of the deadliest forms of stroke, research suggests.
Scientists found that combining the test with a brain scan could provide key genetic information that may help identify those most at risk from a second stroke.
Experts say the new approach could revolutionise the way doctors manage strokes caused by bleeding in the brain, known as intracerebral haemorrhage (ICH), which accounts for up to 50%of all strokes worldwide. Around half of those affected die within one year.
Researchers used the blood test and brain scan images to detect a condition known as cerebral amyloid angiopathy (CAA), which is caused by a build-up of a protein known as amyloid in the walls of blood vessels in the brain.
CAA can cause ICH and is linked to a higher risk of further strokes and dementia.
University of Edinburgh researchers used computed tomography (CT) scans in more than 100 patients who died following their first ICH.
They collected blood samples to test a gene called APOE, which is linked to CAA.
By combining simple CT scan images with a genetic blood test, researchers could accurately spot if an ICH had been caused by CAA.
Dr Mark Rodrigues, Wellcome Trust Clinical PhD Programme Fellow at the University of Edinburgh, said: "Identifying the cause of a brain haemorrhage is important to planning patient care.
"Our findings suggest that the combination of routine CT scanning with APOE gene testing can identify those whose ICH has been caused by CAA - a group who may be more at risk of another ICH or dementia."
This new approach could help identify people who are at higher risk after their ICH, scientists say.
It could also improve ICH diagnosis in developing countries as CT scanning and blood testing is available worldwide.
The study is published in Lancet Neurology and was funded by the Medical Research Council, Stroke Association and Wellcome Trust.