Non-invasive virtual colonography allows an evaluation of the entire colon, without the risks, such as bowel perforation, or complications from sedation associated with standard colonography. VC is accurate in identifying significant polyps and is attractive to many patients who are simply not willing to undergo the more invasive traditional colonography.
Early studies show that VC is comparable to conventional colonography in terms of identifying polyps six millimeters or greater in size. The VCU Department of Radiology use VC as a diagnostic tool to confirm or rule out the possibility of cancer. If large polyps are identified, traditional colonoscopy is required for biopsy and removal.
The VC procedure itself calls for the patient to lie on the CT scan table while the colon is partially inflated using a tiny air tube. Two five-second CT scans are performed, one with the patient on his or her back and the other with the patient lying on his or her stomach. In less than five to ten minutes, the examination is complete; no sedatives are required for this screening method.
Using data acquired from the CT scans, two-dimensional and three-dimensional images of the colon are obtained. VC relies on specially developed computer software to recreate the inside of the patient’s colon, allowing a “fly-through” or “virtual” evaluation of the colon that provides the precise location and size of colon polyps or masses.
According to the American Cancer Society, cancers of the colon and rectum combined are the second leading cause of cancer-related deaths overall and the third most common cancer for both men and women. Screening and early removal of colon polyps can prevent the development of cancer. Although there are high-risk determinants, 75 percent of all colon cancer cases occur in people with no known predisposing factors.