Computed tomography (CT), sometimes called CAT scan, uses special x-ray equipment to obtain many images from different angles, and then join them together to show a cross-section of body tissues and organs. CT scanning provides more detailed information on head injuries, brain tumors, and other brain diseases than do regular radiographs (plain x-ray films). It also can show bone, soft tissues, and blood vessels in the same images. CT of the head and brain is a patient-friendly exam that involves radiation exposure.
You should wear comfortable, loose-fitting clothing for your CT exam. Anything that might interfere with imaging of the head—such as earrings, eyeglasses, dentures, dental implants, or hairpins—should be removed. No special preparation is needed for a CT scan of the head unless you are to receive a contrast material—a substance that highlights the brain and its blood vessels and makes abnormalities easier to see. If the radiologist believes that an intravenous (IV) injection of a contrast material will be helpful, you will be asked in advance whether you have had allergies in the past or have ever had a serious reaction to medication. Many contrast materials contain iodine, which can cause such a reaction in persons who are allergic.