Brain in ischemic stroke. Coloured FLAIR and diffusion magnetic resonance imaging (MRI) scans of sections through the brain of a 62-old patient six hours after an ischemic stroke of the middle cerebral artery in the right side of the brain. A stroke, or cerebrovascular accident (CVA), is the rapid loss of brain function due to disturbance in the blood supply to the brain. This can be due to haemorrhage (bleeding), or ischemia (lack of blood flow) caused by a blockage, as seen here. Here, the stroke has caused complete paralysis (hemiplegia) of the left side of the body.