CT stands for computed tomography. CT colonography uses a CT scanner to produce detailed pictures of the colon and rectum. This test can be used to help detect cancers and other bowel conditions.
The major reason for doing CT colonography is to look for polyps or cancers in the colon or rectum. Polyps are small growths on the inside of your bowel. They are usually harmless but some polyps can develop into cancer.
CT colonography can be used if you have symptoms such as changes in your bowel habit, weight loss or blood in your faeces (stools). It can also be used to screen people who are at risk of developing bowel cancer. CT colonography is often used in people who are too frail to have a colonoscopy, or if there are other reasons why a colonoscopy would not be suitable.
Bowel preparation is required (Two days laxatives/drink prior to scan). The test begins by positioning you lying on your left side on the CT examination table . A very small, flexible tube will be passed a small way into your rectum to allow gas (carbon dioxide) to be gently pumped into the colon. The gas helps to distend (open) the colon as much as possible which gets rid of any folds or wrinkles that might hide polyps or growths.
You will be turned flat on your stomach. Next, the table will move through the scanner. You may be asked to hold your breath for about 5 seconds. As you move through the scanner the pictures will be taken. You will then be turned on to your back and taken through the scanner again.
Once the scan is done, the tube is removed and you will be allowed to get down from the table.
The CT scan itself is painless. You cannot see or feel X-rays. You will be asked to stay as still as possible, as otherwise the scan pictures may be blurred.
The Venflon is removed 15 minutes after the scan.
You may feel discomfort as the air is passed into the bowel. The gas is absorbed by the bowel so you should not feel bloated for long.