Computed tomography (CT or CAT scan) was introduced in the United States in the early 1970s. It revolutionized the practice of neurology and neurosurgery by letting doctors see inside the brain without surgery for the first time. The CT scan is normal in most people with epilepsy. Abnormalities that might be seen are atrophy (shrinking of the brain), scar tissue, strokes, tumors, or abnormal blood vessels.
Like ordinary x-rays, CT scans expose the patient to radiation. However, the amount is low and the procedure is safe even if it needs to be repeated several times. The scanner is a large machine, but less confining for patients than the machine used for MRI.
The advantages of CT scanning include speed and easy availability in most places. It has lower resolution than MRI for showing brain structures, however, and it is not as good at discriminating between the brain's gray matter and white matter.