A CAT or CT scan is an x-ray of the brain. This special scan shows if there is any bleeding into the brain or any scars on the brain caused by blocked blood vessels.
You'll be glad to know it is a painless test and can be done while you lie on a couch – the couch moves through a machine shaped like a doughnut.
Sometime an injection of colourless dye is given into a vein in the arm or hand, which causes a little discomfort for a few minutes (like an injection at the dentist) – this can be important because it can help the doctor to see the blood flow in the brain much better and can help them explain to you about your stroke. The test can take anything from 15 to 30 minutes.