New Zealand has one of the highest incidences of bowel cancer in the world. If caught early this is a curable disease. Most bowel cancers start as polyps. Polyps are growths arising from the surface of the bowel that may grow into cancers.
CT colonography is a CT scan to look at the colon, or large bowel. The main purpose of CT colonography is to look for cancer or large polyps in the large bowel. CT colonography is also an excellent test for diagnosing diverticulitis (where pouches develop in the wall of the colon) or as investigation if you have symptoms suggestive of bowel problems. Another reason to have a CT colonography is if you have had a difficult or incomplete colonoscopy when the whole bowel may not have been completely or confidently assessed.
Preparation: In order to study the large bowel, some preparation is required to cleanse the bowel.
During the CT colonography test, the bowel is filled with carbon dioxide. This causes it to expand so that the inside wall of the bowel can be seen on the CT scan images. After the CT scan is completed, computer software allows the radiologist to analyse the colon. If a cancer or significant sized polyp is found, a further test called colonoscopy is recommended to take a biopsy (a small tissue sample) or remove a polyp. CT colonography is the safest way of examining the large bowel and it does not require sedation.