Radiology & Imaging of South Texas, LLC

Virtual Colonoscopy

What is CT Virtual Colonoscopy?
Virtual Colonoscopy
CT Colonography, also called CT Virtual Colonoscopy, is a procedure that uses CT technology to create an animated, 3-D image of the large intestine to look for signs of pre-cancerous growths - called polyps. CT Virtual Colonoscopy is ideal as a screening tool for patients that are not experiencing any symptoms or for patients who have an incomplete conventional colonoscopy. During the procedure, images will be taken of the large intestine while you are lying face up and also face down on the CT table. The large intestine will be expanded with carbon dioxide gas for better viewing. Once the procedure is complete, one of our Radiologists will evaluate the results for any abnormalities. If a polyp is detected, you may need to have a conventional colonoscopy as CT Virtual Colonoscopy does not allow for the removal of tissue samples.

How does CT Virtual Colonoscopy differ from Conventional Colonoscopy?
The main difference between a CT Virtual Colonoscopy and a conventional colonoscopy is the way a physician sees inside the colon. Conventional colonoscopy requires that the patient be sedated and a long flexible tube called a colonoscope is used to view the inside of the colon. CT Virtual Colonoscopy is minimally invasive and does not require the patient be sedated.

Colon Cancer Risk Factors
Colon cancer is the third leading cause of cancer death in the United States for both men and women. The American Cancer Society estimated over 108,000 new colon cancer cases and over 40,000 rectal cancer cases were diagnosed and over 49,000 deaths occurred in 2008.

Risk Factors:

  • Age - patients over 50 years of age have an increased risk of colon cancer
  • Inflammatory bowel disease
  • Family history
  • Low fruit/vegetable intake
  • Low fiber / High fat diet
  • Obesity
  • Tobacco and alcohol use

Advantages of CT Virtual Colonoscopy
Performing CT Virtual Colonoscopy with CT technology has many benefits. Some of these benefits include:

  • Cost
  • Lower risk of complications
  • No pre-medication or sedation is required
  • Greater control over colonic distention (inflation)
  • Does not require the insertion of a colonoscope into the colon
  • No “blind” spots
  • Better detection of flat lesions
  • Increased differentiation of lesions resulting in fewer unnecessary biopsies and risks of hemorrhage
  • Clearer, more detailed images than conventional x-ray
  • Shorter exam time than conventional colonoscopy

Indications for CT Virtual Colonoscopy
Physicians may order CT Virtual Colonoscopy for their patients in cases when patients require a screening exam for colon cancer but have no symptoms, if they are frail or elderly or if a conventional colonoscopy can not be completed. CT Virtual Colonoscopy is the most accurate radiology exam for polyp detection and the least invasive.

Common indications for CT Virtual Colonoscopy:

  • Over 50 years of age
  • Colon cancer screening exam
  • Incomplete colonoscopy
  • Patient autocoagulated
  • Patient choice
  • Contraindicated for conventional colonoscopy

Preparing for your CT Virtual Colonoscopy
The quality of your virtual colonoscopy exam is dependent in part on the quality of your bowel preparation. To assure the best possible outcome, this preparation should be taken exactly as directed.

Two days before your exam:

  • STOP fiber supplements and follow a LOW-FIBER diet.
  • Avoide high fiber items such as beans, nuts, seeds and whole grain items.

The oral contrast material (Redi-Cat 2 and Gastrografin) will need to be taken IN ADDITION TO the LoSo Prep colon cleansing kit that has been prescribed for you to take on the day of your exam. This is necessary to mark any remaining stool, for differentiation from polyps.

At breakfast on the day prior to your exam:

  • Begin a clear liquid diet and follow the remaining directions on the LoSo Prep kit packet.

At 6pm on the day prior to your exam:

  • Drink the bottle of Redi-Cat 2 (225 ml).
  • Drink 1 full 8oz glass of water as instructed in the LoSo Prep kit.

At 9pm on the day prior to your exam:

  • Drink the bottle of Gastrografin (60ml). The Gastrografin may be mixed with water or clear soda (Sprite or 7-Up)
  • Drink 1 full 8oz glass of water as instructed in the LoSo Prep kit

Day of your exam:

  • If you are still passing any formed stool you should not come to radiolgoy. Contact us at 888-6684 for further instructions.