What is a Virtual Colonoscopy or CT Colonography?

CT colonography, also known as virtual colonoscopy, is a minimally invasive alternative to traditional optical colonoscopy.  It uses a computed tomography (CT) scan to screen for polyps and other abnormalities in the large intestine.  Because it is less invasive than conventional colonoscopy, it carries a lower risk of complications and does not usually require sedation. In the majority of patients who receive virtual colonoscopy, no polyps are found, and the more invasive optical colonoscopy is unnecessary.

The American Cancer Society recommends that beginning at age 50, people at average risk for developing colorectal cancer undergo regular screening. A variety of screening tests are available, including conventional colonoscopy, which must be repeated every ten years, as well as virtual colonoscopy, which patients should undergo every five years.  People at increased risk of colorectal cancer, such as patients with a personal or family history of colorectal cancer or related conditions, are advised to screen earlier and/or more often. Discuss your risk level and screening options with your health care provider to choose the best course for you.

What Happens During a CT Colonography Test at Iowa Radiology?

Two days before the exam, you will follow a bowel cleansing regimen that includes a limited diet and a bowel preparation.  Speak with your physician about any sensitivity you may have to the bowel preparation, particularly if you suffer from heart, kidney, or liver disease. Upon arrival at our office, you will be taken into an exam room to change into a gown and speak with our technologist about your medical history.  You will lie on your side on the exam table as a very small, flexible tube is inserted just two inches into the rectum. This allows carbon dioxide to be pumped into the colon in order to inflate it for clear viewing. This may cause mild discomfort, similar to gas pains. Once the colon is inflated, you will roll onto your back and then onto your stomach while the images are taken. The entire exam takes only about 15 minutes.

After the test is complete, you may engage in your normal activities. Because no sedative is necessary, you do not need to arrange for a driver.  You body should quickly absorb the carbon dioxide, and you should experience little discomfort following the exam.  You should expect your physician to receive our report of the results within one business day.

How Often is Follow-Up Necessary?

According to the American College of Gastroenterology, depending on the age of the patient, the odds of being called back for a colonoscopy and polypectomy after a virtual colonoscopy are approximately 12%-25%.

What Are the Advantages of Virtual Colonoscopy?

CT colonography holds several advantages over conventional colonoscopy:

• It is less invasive.
• It carries a lower risk of perforating the colon.
• It does not require sedation.
• It occasionally identifies abnormalities outside of the colon, such as cancers or abdominal aortic aneurysms.
• It provides a good alternative to patients at increased risk of complications from conventional colonoscopy.
• It allows for the examination of patients who have failed traditional colonoscopy.

Iowa Radiology offers CT colonography at the Downtown Des Moines location.  Contact us with any questions you have about your procedure.  We are happy to help.

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