Computed tomography (CT) is an X-ray technique that produces more detailed images of your internal organs than a conventional X-ray can. The CT computer displays detailed picture images of organs, bones and other tissues. This procedure also is called CT scanning, computerized tomography, or computerized axial tomography (CAT).
What is it?
CT is a noninvasive way to view your internal organs and tissues. Occasionally, your doctor may order a CT scan with contrast. In that case, a radioactive dye will be injected into your veins before the scan.
CT is used to help:
- Diagnose muscle and bone disorders, such as osteoporosis, tumors or fractures
- Determine whether you have a tumor or blood clot
- Check for cancer and see if a cancerous tumor is growing
- Find internal injuries or bleeding
How do I prepare?
The type of preparation you’ll need before a CT depends on what part of the body is being examined and whether or not contrast material is needed. You will be given specific instructions when your CT is scheduled. Here are some general guidelines:
- Don’t wear jewelry or other metal objects as these will interfere with the scan.
- You may need to remove eyeglasses, dentures or dental bridges.
- Your doctor may prescribe laxatives or suppositories to be used before your CT to clean out your digestive tract.
- You may need to fast (not eat solid food) for a few hours before the CT scan.
- Please tell us if you have ever had a problem with contrast materials, have food allergies or are allergic to iodine.
What to expect
Please plan to arrive 15 minutes before your scheduled appointment time. This will help ensure that your CT scan can be completed on schedule. Please allow at least one hour for your CT scan. Most scans take from 15 to 60 minutes.
During the test
During the CT scan, you will be asked to lie very still on a table because movement can blur the images. You may be asked to hold your breath for a short time when the images are taken. The table slowly passes through the center of a large X-ray machine. You may hear whirring and clicking sounds during the procedure. A technologist will be in a separate room supervising your exam and monitoring the images as they appear on the computer screen. The technologist can see and hear you, and you can communicate via intercom.
If a contrast material is injected intravenously (into your vein), you may feel flushed, or you may have a metallic taste in your mouth. These are common side effects. If you experience shortness of breath or any unusual symptoms, please tell the technologist.
After the test
Generally, you can resume your usual activities and normal diet immediately. If a contrast medium was used, your doctor or the radiography staff will give you any special instructions. These will likely include drinking lots of fluids to help pass the medium from your body.
CT images usually are printed from the computer onto film. A radiologist interprets these images and sends a report to your doctor. Your doctor will contact you to discuss the results.