A computed tomography (CT) is a test that combines X-rays and computer scans to create detailed pictures of your bones and soft tissues, such as organs and blood vessels.
There’s very little you need to do to prepare for your CT scan. If you don’t have congestive heart failure and aren’t on dialysis, you should drink 64 ounces of water before your exam. This equals eight 8-ounce glasses. If possible, start drinking water 12 hours before your scheduled appointment time so that you’ll stay hydrated. However, you don’t need a full bladder for the test. So, you can use the restroom before the test begins.
If you’re getting a CT scan of your chest or heart, you should stop drinking or eating anything containing caffeine several hours before your exam.
Be sure to wear comfortable clothing to wear during the CT scan. Also, all jewelry and other metallic objects must be removed from the area being scanned. This includes metal that is often part of clothing, such as snaps, belts and underwire bras.
You’ll need to arrive at least an hour before your appointment time to check in and complete paperwork. If necessary, your IV (intravenous line) will also be started during this time.
It’s often necessary to use a special dye (contrast) to make a part of your body show up more clearly during the CT scan. If you need the dye, you may get it as something to drink and/or it might be administered through an IV. If you drink the contrast dye, you’ll need to arrive at least 90 minutes before your appointment time.
During the CT scan, you’ll lie on a special table. It will move you through the center of the doughnut-shaped CT scanner — but nothing will touch you. As you’re moved through the scanner, you’ll need to stay as still as possible. You may be asked to hold your breath for a few seconds as each scan is made.
Most CT scans take 15 to 20 minutes. You should plan for your entire visit to be at least 1½ hours. In some cases, it may take longer.
After your CT scan, you’ll most likely be able to go back to your normal activities and diet. If you were given the contrast dye, but didn’t drink the recommended amount of water before your CT scan, you should drink 64 ounces of water over a 12-hour period after the exam. However, do NOT do this if you have congestive heart failure or are on dialysis.