Stroke. Computed tomography (CT) scan of a section through the brain of a patient 24 hours after a haemorrhagic stroke, showing an accumulation of blood (bright, centre left) in the brain. A stroke, or cerebrovascular accident (CVA), is the rapid loss of brain function due to a disturbance in the blood supply to the brain. Here, arterial hypertension (high blood pressure) caused a blood vessel to burst, leaking blood (haemorrhaging).