Preparing for a CT Scan

Computed tomography (CT) scans require preparation on the part of the patient. Your health care team will ask that you do not drink anything for one hour prior to the test. If IV contrast is to be used during the scan, you may be asked not to eat for at least four hours prior to the scan.
What to Tell Your Health Care Team
Be prepared to provide a complete list of any medications you are currently taking, both prescription and nonprescription. If you have had recent or prior CT scans elsewhere, please bring them along for the radiologist to compare with the new scan.
Please be prepared to tell your doctor or radiologist all details concerning the following aspects of your current health, including whether or not:
  • You are pregnant
  • You are diabetic (remind your doctor if you are taking the diabetes medicine metformin, which should be temporarily discontinued in people undergoing a test using contrast with iodine)
  • You have had any side effects to an IV contrast in the past
  • You have had or are presently being treated for an infection
  • You have a pacemaker or cardioverter (this won't prevent you from having the examination)
  • You have allergies, especially medications, iodine or shellfish (such allergies could increase your risk of having and allergic reaction to the IV contrast)
  • You have had a recent imaging test using barium contrast

What to Wear


On the day of the exam, wear comfortable, loose-fitting clothing. Metal objects can affect the image, so avoid clothing with zippers and snaps. You must put on a hospital gown and remove watches, jewelry, or any other metal objects you might be wearing (including hairpins, glasses, hearing aids and any removable dental work).