A CT colonography, or virtual colonoscopy, is a diagnostic procedure designed to screen for polyps or cancer in the large intestine. Polyps are growths on the inner lining of the intestine which may become cancerous if left unchecked.
Colonography screening is intended to find these growths in their early stages, before cancer has developed, so that they can be safely removed. Most physicians agree that people over the age of fifty should be screened every seven to 10 years for polyps. Individuals at increased risk, or with a family history of colon cancer, may start screening more frequently and at a younger age. A history of polyps, a family history of colon cancer, or the presence of blood in the stool are among the risk factors for these types of cancer.