Stroke. Coloured computed tomography (CT) scan of a cerebrovascular accident (stroke). Stroke is a condition where blood flow to the brain is interrupted or reduced, causing death of brain tissue (red). This is an ischaemic stroke, where blood flow was reduced but not eliminated. Stroke can be caused by a blood clot or a ruptured blood vessel. Symptoms depend on the brain region affected, and can include partial paralysis, impaired co-ordination, loss of sight and language difficulties. Stroke is a major cause of death. Treatments include surgery, drugs and rehabilitation courses.