Unlike other colon cancer screening tests, this imaging test doesn't use a scope to examine your colon. Learn how it works and what to expect.
Virtual colonoscopy is a minimally invasive exam to screen for cancer of the large intestine (colon cancer). Virtual colonoscopy is also known as screening CT colonography.
Unlike traditional colonoscopy, which requires a scope to be inserted into your rectum and advanced through your colon, virtual colonoscopy uses a CT scan to produce hundreds of cross-sectional images of your abdominal organs. The images are combined and digitally manipulated to provide a detailed view of the inside of the colon and rectum. Virtual colonoscopy requires the same bowel preparation as traditional colonoscopy.
Virtual colonoscopy is one option used to screen for colon cancer. Discuss your colon cancer screening options with your doctor to determine whether virtual colonoscopy is the right option for you.
Virtual colonoscopy is used to screen for colon cancer in people who are at least 45 years old.
Your doctor may suggest virtual colonoscopy if you:
You aren't a candidate for virtual colonoscopy if you have:
Studies have shown that virtual colonoscopy has detection rates similar to those of traditional colonoscopy for cancer and most polyps of biological importance.
Because virtual colonoscopy involves imaging the entire abdominal and pelvic area, problems unrelated to colon cancer — such as an abnormality in the kidneys, liver or pancreas that may or may not be important — could potentially be detected. This may lead to additional testing.
Virtual colonoscopy is generally safe. Risks include:
Not all health insurance providers pay for virtual colonoscopy for colon cancer screening. Check with your health insurance provider to see which tests are covered.
Before a virtual colonoscopy, you'll need to empty your colon. Any residue in your colon may obscure the images taken during the exam.
To empty your colon, follow your doctor's instructions carefully. You may be asked to:
You'll wear a gown but likely no other clothes. Sedation usually isn't necessary, but you may be given medication to relax your colon.
You'll begin the exam lying on your side on the exam table, usually with your knees drawn toward your chest. A nurse or technologist will place a small tube (catheter) inside your rectum to fill your colon with air or carbon dioxide as you do a log roll on the table. The air or gas helps create clear images and may cause a feeling of pressure in your abdomen.
For the next part of the exam, you'll lie on your back. The exam table will be moved into the CT machine, and your body will be scanned. Then you'll turn over to lie on your abdomen or your side and your body will be scanned again.
You may be asked to turn and hold various other positions as well as hold your breath at times.
A virtual colonoscopy typically takes about 15 minutes.
You can resume your usual activities after your virtual colonoscopy. You may feel bloated or pass gas for a few hours after the exam as you clear any remaining air or gas from your colon.
Your doctor will review the results of the colonoscopy and then share them with you.
Your test results may be: