Definition
Virtual colonoscopy (VC) combines MRI or CT scans with sophisticated computer software to produce images of the colon and rectum. The test, which is less invasive than conventional colonoscopy , detects polyps in the colon.
Other Names
Colonoscopy - virtual
How the Test is Performed
Patients must follow a strict bowel-emptying procedure the day before, just as they would for a standard colonoscopy. The test is performed in the radiology department of a hospital or medical center. Unlike conventional colonoscopy, no sedatives are needed and no scope is used.
You will lie down on your left side on a narrow table that is connected to an MRI or CT machine. Your knees will be up toward your chest. A small, flexible tube will be ...
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Definition
Virtual colonoscopy (VC) combines MRI or CT scans with sophisticated computer software to produce images of the colon and rectum. The test, which is less invasive than conventional colonoscopy , detects polyps in the colon.
Considerations
Differences between virtual and conventional colonoscopy include:
- Virtual colonoscopy uses no sedation, and patients are usually able to resume normal activities immediately after the test. Conventional colonoscopy involves sedation, and usually the loss of a work day.
- If a polyp is found with virtual colonoscopy, the patient must have a conventional colonoscopy to remove the abnormality. Conventional colonoscopy allows for the immediate removal of polyps .
- Both procedures can spot polyps that have reached a large, worrisome size. However, virtual colonoscopy is not as detailed as a conventional colonoscopy, and may miss polyps smaller than 10 millimeters in diameter or flat lesions.
- Virtual colonoscopy can view the colon from many ...
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Other Names
Colonoscopy - virtual
How the Test will Feel
The x-rays are painless. Pumping air into the colon can create temporary cramping or gas pains.
How to Prepare for the Test
Preparations can vary, depending on your health care provider. Everyone undergoing any type of colonoscopy must completely empty their bowels before the exam. This may be done using an enema or laxatives combined with a liquid diet the day before the test. The bowel must be completely emptied until no solid matter remains.
Unfortunately, diarrhea is common during preparation. Drink plenty of clear liquids, such as apple juice and chicken broth, to avoid dehydration .
Make sure you tell your health care provider about any medications you are taking. Youll be told which you can take, and which you should temporarily stop. CT and MRI scanners are very sensitive to metals. Dont wear jewelry the day of your exam. Youll be asked to wear a hospital gown for ...
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Normal Results
Normal findings are images of a healthy intestinal tract.
Risks
- Radiation exposure
- Nausea, vomiting, bloating, or rectal irritation caused prep medications
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References
Virtual Colonoscopy, The Medical Letter , February 14, 2005; 1202:15
Van Dam, J. et al. CT Colonography. Gastroenterology . 2004; 127: 970-984
Lieberman, D. Colonoscopy: Good as Gold? Ann Intern Med . 2004; 141: 401-403
Pickhardt, P. et al. Location of Adenomas Missed by Optical Colonoscopy. Ann Intern Med . 2004; 141:352-359
