Some CT scans require the use of intravenous (IV) contrast media. If a contrast medium will be used with your study, you may drink only water 3 hours prior to the exam. Contrast materials used in CT usually contain iodine (a clear substance) or barium (a white chalky substance.
Patients receiving iodine contrast will be asked to fill out a patient health history/contrast screening sheet. Based on the answers given or if you are older than 60, a blood test is required before your CT can be scheduled.
Iodine is a heavy metal and shows up "bright" or white on a CT image. If iodine contrast is given by IV, veins and arteries will be enhanced on the images. If the contrast material has been digested or given rectally, the stomach, small intestine, and colon will be enhanced. The contrast agent will leave your body naturally within a few hours.
You may feel a brief warming sensation or metallic taste in your mouth after IV injection.
Drink additional fluids for 24 to 48 hours after contrast to help your kidneys flush the contrast from your body.