A colonography is a visual recording of the colon or large intestine obtained using computed tomography (CT) technology. Like a colonoscopy, the purpose of a colonography is to screen the colon for polyps or other abnormalities that could indicate a risk factor for colon cancer or other colon disease. A colonography is less invasive than a colonoscopy, but presents different risks and benefits in comparison.
Generally speaking, the preparation for a colonography is the same as that for a colonoscopy. A thorough cleaning out of the bowels is necessary the day before. A colonography does not require sedation, though a mild muscle relaxer may be injected immediately prior to the procedure.
A colonography is obtained by first slightly inflating the colon with air. This distends the colon just enough to see any abnormalities that might be hidden within the folds of the colon wall. A series of images is then taken with the CT equipment and a computer puts the images together for a radiologist to read.
Though colonography minimizes the risk of perforating the colon and is less invasive than a colonoscopy, the procedure does have a few drawbacks. To begin with, the black and white images make it potentially difficult to spot problems less obvious than polyps, such as small lesions. A colonography also involves exposure to x-ray radiation.
Another drawback for many patients lies with insurance companies. Most insurance companies will not pay for a colonography as a part of the recommended yearly colon screening for patients over 50, even though the procedure is less expensive to perform than colonoscopies. Some insurance companies will pay for a colonography if it is ordered as part of a diagnosis for a specific problem.
A colonography serves as a good screening tool for colon health, because many screened patients do not actually have polyps present in their colon and the procedure is less invasive than colonoscopy. However, in the event that polyps are found, the more traditional colonoscopy offers the opportunity to perform an immediate biopsy and to remove any polyps if necessary. Patients who obtain a colonography and are found to have polyps will be sent for a traditional colonoscopy. However, for people who fear a conventional colonoscopy for any reason, the colonography is better than no screening at all. Talk to your doctor if you have concerns about colon screening.
