Follow these instructions to ensure a smooth appointment.
Prepare for Your Appointment
You should wear comfortable, loose-fitting clothing to your exam. You will be given a gown to wear during the procedure.
Women should always inform their physician and the CT technologist if there is any possibility that they may be pregnant.
The bowel-cleansing regimen for CT colonography is similar to that for a colonoscopy. Your diet will be restricted to clear liquids the day before the examination. It is very important to clean out your colon the night before your CT colonography examination so that the radiologist can clearly see any polyps that might be present. You will be asked to take either a set of pills or a liquid laxative. Some common preparations are NuLytely®, Go-Lytely® (Polyethylene glycol electrolyte solutions) or Magnesium Citrate or bisacodyl tablets. Additional agents may also be taken the day before the exam. These may include small quantities of barium and iodinated liquids. These agents help the radiologist better distinguish stool from polyps by “tagging” the remaining stool and fluid.
Be sure to inform your physician if you have heart, liver or kidney disease to be certain that the bowel prep will be safe. Your physician can advise you on dietary restrictions prior to the exam. You will be able to resume your usual diet immediately after the exam.
What to Expect
As with conventional colonoscopy, the success of the exam depends largely on how well you clear your colon. CT Colonography does require a bowel preparation the day prior to the scan, which is a combination of low residual foods, water, magnesium citrate, bisacodyl tablets and a suppository. The preparation kit is given directly to the patient, and contains all the necessary medications and instructions for the test.
To make the images, your colon is filled with carbon dioxide by inserting a small catheter inside the rectum. You lie on your side and your back while the images are made. You may be asked to hold your breath for several seconds to limit abdominal movement and avoid distorting the images.
CT Colonography is typically faster than traditional colonoscopy. A scan of your entire colon takes about 10 minutes.
A CT Colonography is not advisable for patients with rectal bleeding, history of diverticulitis, Crohn’s Disease or those who have a recent colonoscopy with positive findings.
How This Service Works
For CT colonography, the computer generates a detailed 3-D model of the abdomen and pelvis, which the radiologist uses to view the bowel in a way that simulates traveling through the colon. This is why the procedure is often called a virtual colonoscopy. Two dimensional (2-D) images of the inside of the colon as well as the rest of the abdomen and pelvis are obtained and reviewed at the same time.
The major reason for performing CT colonography is to screen for polyps or cancers in the large intestine. Polyps are growths that arise from the inner lining of the intestine. A very small number of polyps may grow and turn into cancers.
The goal of screening with CT colonography is to find these growths in their early stages, so that they can be removed before cancer has had a chance to develop. The American Cancer Society (ACS) recommends that women and men undergo screening for colon cancer or polyps beginning at age 50. As part of its recommendation, ACS suggests CT colonography as an option once every five years. Individuals at increased risk or with a family history of colon cancer may start screening at age 40 or younger and may be screened at shorter intervals (for example, having a colonoscopy every five years). Risk factors for the disease include a history of polyps or having a family history of colon cancer. Signs and symptoms of colon cancer include a persistent change in bowel habits, the presence of blood in the stool, abdominal discomfort or pain, bloating and unexplained weight loss.
For additional details concerning the above procedures, please visit www.radiologyinfo.org