CT Scan Frequently Asked Questions

What is a CT scan?

A CT scan — also called Computerized Tomography or just CT—is an X-ray technique that produces images of your body that visualize internal structures in cross section rather than the overlapping images typically produced by conventional X-ray exams. CT scans use an X-ray unit that rotates around your body and a powerful computer. The result with CT scans is a set of cross-sectional images, like slices, of the inside of your body.

Should I do anything special to prepare for a CT scan?

How you prepare for a CT scan depends on which part of your body is being scanned. You may be asked to remove your clothing and wear a hospital gown. You’ll need to remove any metal objects, such as jewelry, that might interfere with image results. Some CT scans require you to drink a contrast liquid before the scan or have contrast injected into a vein in your arm during the scan. A contrast medium blocks X-rays and appears white on images, which can help emphasize blood vessels, bowel or other structures. If your test involves a contrast medium, your doctor may ask you to fast for a few hours before the test.

Can I take my medicine before a CT scan?

Yes, please take medicines before the CT scan, with the exception of diabetic medicines. Consult your physician before the test for instructions.

How long will it take to do a CT scan?

Expect the exam to last no longer than an hour, depending on the preparation needed and whether it includes the use of a contrast medium. The scan itself may take less than a minute on the newest machines. Most scans take just a few minutes to complete.

Will the radiation that I receive from the CT scan hurt me?

CT scans are similar to those of conventional X-rays. During the CT scan, you’re briefly exposed to radiation. But doctors and other scientists believe that CT scans provide enough valuable information to outweigh the associated risks.

What will I experience during and after the procedure?

During the CT scan, you lie on a narrow table that slides through the opening of the gantry. You may lie on your back, side or stomach, depending on the area to be scanned. The table can be raised or lowered. Straps and pillows may help you stay in position. During a CT scan of the head, the table may be fitted with a special cradle that holds your head still. CT scans are painless. If your exam involves use of an intravenous contrast medium, you may feel a brief sensation of heat or experience a metallic taste in your mouth. If you receive the contrast medium through an enema — to help highlight your lower gastrointestinal region — you may feel a sense of fullness or cramping. After the exam you can return to your normal routine. If you were given a contrast medium, your doctor, a nurse or the CT technologist performing the scan may give you special instructions. You may be asked to wait for a short time in the radiology department to ensure that you feel well after the exam. After the scan, you’ll likely be told to drink lots of fluids to help your kidneys remove the medium from your body.

Will I have to take a CT contrast or dye, and can I be allergic to it?

It depends on which part of your body is being scanned. Although rare, the contrast medium Involved in a CT scan poses a slight risk of allergic reaction. Most reactions are mild and result in hives or itchiness. For people with asthma who become allergic to the contrast medium, the reaction can be an asthma attack.

In rare instances, an allergic reaction can be serious and potentially life-threatening — including swelling in your throat or other areas of your body. If you experience hives, itchiness or swelling in your throat during or after your CT exam, immediately tell your technologist or doctor.

If you’ve had a reaction to a contrast medium in the past, and you need a diagnostic test that may require a contrast medium again, talk to your doctor. Be sure to let your doctor know if you have kidney problems, since contrast material that’s injected into a vein is removed from your body by your kidneys and could potentially cause further damage to your kidneys.

If you have had a prior reaction to contrast media or have asthma or allergies, there’s an increased risk of a reaction to the contrast medium. Diabetes, asthma, heart disease, kidney problems or certain thyroid conditions may increase your risk of a reaction to contrast media.

Will I need someone to drive for me after the CT scan?

No, the CT scan is a safe test that will not affect your ability to drive.

How and when will I get my results?

CT images are stored as electronic data files and usually reviewed on a computer. A radiologist interprets these images and sends a report to your doctor.

Please contact us to learn more about CT scans at UAMS.