Computed tomography (CT) is an imaging test that combines X-rays and a computer to make scans.
The result is a detailed picture that can show problems with soft tissues (such as the lining of your sinuses), organs (such as your kidneys or lungs), blood vessels, and bones.
Tell the technologist
Be sure to tell the technologist if you:
- Have allergies or kidney problems
- Take diabetes medicine
- Are pregnant or think you may be
- Ate or drank anything before the test
Before your test
- Tell your healthcare provider if you’ve ever had a reaction to a special X-ray dye (contrast material). Also tell them if you have a history of abnormal kidney function. If you had a past reaction, you may need to take medicine before your scan. So be sure to tell your provider ahead of time. You may not be able to have IV (intravenous) contrast material, if your kidneys aren’t working correctly.
- Tell the provider about all the medicines you take. This includes prescription and over-the-counter medicines. It also includes vitamins, herbs, and other supplements. Ask if it’s OK to take them before the test.
- Follow any directions you’re given for not eating or drinking before the test. Your provider will give you instructions if required. You may have to drink contrast material before arriving for the test. This depends on the type of test you’re having. Your provider or the imaging site will provide this for you.
- The length of the procedure may vary, depending on your condition and your provider’s practices.
- Arrive on time to check in.
- When you arrive, you may be asked to change into a hospital gown. Remove all metal near the part of your body that will be scanned. This includes jewelry, glasses, and dentures. Women may need to remove a bra that has a metal underwire.
During your test
- You may be given contrast material through an IV line or by mouth.
- You’ll lie on a table. The table slides into the CT scanner.
- The technologist will operate the scanner from a control room. They’ll be able to hear you and speak to you.
- The technologist will ask you to hold your breath for a few seconds during your scan.
- Alert the technologist if you have chest pain, shortness of breath, swelling in the throat, or a feeling that your heart is racing (palpitations).
- If you receive IV contrast material, you may:
- Feel warm or flushed
- Have a metallic taste in your mouth
- Feel the urge to pee