Overview

Colon polyps have been shown to be the precursor lesions for most colon cancers. Identification and removal of colon polyps before they become cancerous is the goal of colon screening. The VCU Department of Radiology was among the first in Virginia to test and use a more patient-friendly method of screening for colon polyps. Virtual colonography (VC) or CT colonography (CTC) is a noninvasive treatment that uses computed tomography (CT) scanning to determine the presences of colon polyps.
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 exam is complete.

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. The process allows a “fly-through” or “virtual” evaluation of the colon that provides the precise location and size of colon polyps.