A drug that breaks up blood clots in the brains of stroke patients could be used more widely than at present without increased risk, a brain scan study suggests. It had previously been thought that giving the drug to people with signs of early damage in the brain caused by a stroke would increase the chances of them suffering a bleed on the brain -- which can be fatal. The study is the first to show that early tissue damage seen in brain scans does not necessarily indicate an increased risk of bleeding.