When you have a CT scan done, computers and x-rays combine to take pictures of cross sections of your body. "Slices" show bones, muscles, fat, organs and other body parts. CT scans are more detailed than x-rays. They help doctors:
- Diagnose muscle and bone problems, such as tumors and fractures
- Find tumors, infections or blood clots
- Guide a biopsy or radiation treatment
- Find disease and its effects on the body
- See internal injuries and bleeding
How to prepare
On the day of the scan, take your usual pills with a sip of water. Wear clothing with little or no metal in zippers, pins, studs or buttons. You can wear these clothes for the test. Eat normal meals unless your scan is going to be done with contrast medication. Your doctor or the person who helps schedule this test will tell you if contrast is required. In this case, read the section "Contrast medication."
Are you pregnant or do you think you might be?
Tell your doctor. Steps will be taken to protect your baby. The scan may have to be done on a different date.
Contrast medication—also known simply as contrast—makes disease or injury easier to see. If your scan will be done with contrast, you may be told to eat no food for 4 hours before the scan.
Contrast can be given in different ways. It depends on the part of the body that will be scanned. You may swallow it. Sometimes it goes through a needle in a vein in your arm or hand. It might be given through your rectum.
If you are diabetic, over 50 years old or have kidney problems, you may have a blood test. This will show if your kidneys can clean contrast out of your system after the scan.
Contrast may cause an allergic reaction. This is rare. One or more of these might happen:
- Pulse change
- Difficulty breathing
The radiologist will give you medicine to stop these during the test.
During the test
The examination lasts a few minutes. It takes a little longer if contrast is used. You lie still on a narrow table that slowly moves into a large circular opening. The X-ray tube rotates around your body. You may have to hold your breath for a short time. During the scan, the technologist watches pictures on a computer screen. He or she can see you through a window and talk to you on a speaker.
If you have contrast through a needle, you may feel a warm rush in your body and your mouth may taste like metal. These are normal side effects that usually pass in a few minutes.
A doctor called a radiologist will look at pictures taken during your test. A report about your pictures will be sent to your doctor in 24 to 48 hours. It may take longer for you to get this information if you have had other tests. Your doctor needs to see results of all tests before they can be explained.