CT Colonography (CTC)
CT or Computer Tomography is a special X-ray machine that produces an image of a cross-section, or slice, of the body. The scanner consists of a ‘doughnut’ shaped structure, or gantry, about two feet thick, through which you pass on a couch.
The information passes to a computer that then produces a picture of the internal structure of the body. They produce in excess of 600 images of the body, which can be used to show internal structures in 2D and 3D planes.
In CTC we use the 3D packages to get a view of the colon as if we were travelling through it.
Is there any preparation needed beforehand?
As CTC is a very specialized examination of the colon the radiology department will supply you with two sachets of a laxative (usually picolax) to be taken the day before the procedure. You should not eat or drink anything from midnight before the examination. You can take your normal medications. It is important you have a clean colon.
What does a CT Scan involve?
You will be asked to remove some of your clothes and wear a hospital gown. A small cannula will be placed into a vein to allow the administration of a “dye”, known as contrast, to be given. This improves the quality of the scan and demonstrates accurately all the organs and blood vessels in your abdomen.
A CT Colonography (CTC) is similar to a barium enema in a way. You will have been given a laxative the day before the CT to clean the colon. A a small tube will be placed into your bottom in the X ray room to allow air to be instilled. A small injection is then given to relax the bowel (buscopan) and contrast is administered via the cannula prior to the pictures being taken. After the examination you may eat and drink normally.