What is a CT Scan?

A "CT" or "CAT" scan is the term used to describe a radiologic test known as "computerized tomography" (or computed axial tomography). The CT scanner is a doughnut-shaped machine that uses advanced x-ray technology to take pictures of cross-sections of your body, called "slices."

CT can see inside the brain and other parts of the body, into areas that cannot be seen on regular x-ray examinations. CT makes it possible to diagnose certain diseases earlier and more accurately than with other imaging tools. Because most diseases are better treated when found early, CT scans can help save lives.

What can I do to prepare myself for the test?

That day

On the day of your CT scan, please do not eat solid food for four hours prior to your CT appointment. You may, however, have clear liquids (black coffee/tea, broth, clear soups, or juice) during this time in moderate amounts. Restricting solid foods in order to avoid stomach distress is a common safety precaution before many medical procedures.

At the CT scan suite

Plan to arrive at the CT scan suite at least 15 minutes before your scheduled appointment. This will allow the necessary time to prepare your paperwork. You will be asked to fill out a brief questionnaire about your medical history, medications and allergies, and insurance.

If you are having a CT scan of your abdomen or pelvis, you need to arrive 1 hour and 15 minutes before your appointment. You will be asked to drink barium, a fluid that helps mark your intestinal tract so that the radiologist may interpret your scans properly. You will then be asked to wait for one hour before the examination, because it takes that long for the drink to coat your stomach and small intestine. In fact, depending on your medical problem and the type of study that has been requested, you may be asked to drink one bottle of barium sulfate at bedtime the night before the study.

A CT technologist will introduce herself/himself to you, explain the test you are having, and answer your questions. Depending on the part of your body being scanned, you may be asked to remove any metal objects, such as jewelry, and change into a hospital gown.

What happens during the scan?

[patient and technologist]The technologist will bring you into the CT scan room where you will lie down on the patient couch (usually on your back). You should get comfortable because it is very important that you not move during the test. CT examinations differ depending on your medical problem and the part of your body being studied. The radiologist will plan an examination that suits your diagnostic needs.

For example, if your abdomen is being studied, a series of pictures will be taken from your lower chest down to the upper pelvis. During such a study, you will be asked to hold your breath so that the pictures will not be blurred. The machine will make some noise, and the couch may move slightly after each picture. Also, you may receive signals from the technologists (or from the machine) about your breathing. As part of your test, before or during the study, you may be given an injection (by a nurse, technologist or doctor) of a contrast agent. This allows the radiologist to obtain clearer images of your organs. Should you have any discomfort during the test or after the injection, tell the technologist. All the CT personnel are trained and certified and know how to help you.

How long does a CT scan take?

Each examination is tailored to individual requirements, so don't be alarmed if your exam is different from one you've had before, or if some additional pictures are taken after the first series is completed. From start to finish, the picture-taking part of the test usually lasts only 10 to 15 minutes.

When do I get the results?

Your exam will be reviewed radiologists who specialize in this type of imaging. Results are then available to your doctor. A formal written report should also be sent to the requesting doctor. Contact your doctor if you want to know about the results.