How the colon is examined – instrumental examination of the colon, as well as colon X-ray and virtual colonoscopy (CT colonography), requires a clean colon.
This means that thorough bowel preparation with laxatives is needed before the examination, so that the entire bowel wall is cleaned and any abnormalities become visible.
During the instrumental examination, a fibre-optic instrument about as thick as a little finger is passed up through the rectum, into the colon.
The examination is unpleasant, but nowadays some places routinely use painkilling and mildly sedating medication during the procedure, so the patient feels nothing.
With imaging methods, too, it is important to clean out the colonthoroughly. Then a contrast medium mixed with air is introduced through the rectum, and the colon is “photographed”. Tissue samples for histology can only be obtained with an instrumental examination.
