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Computed Tomography

Virtual Colonoscopy 

What is a Virtual Colonoscopy CT Exam?   A CT Scan is (sometimes referred to as a CAT Scan) is a noninvasive medical test to diagnose medical conditions.  A CT Scan combines special x-ray equipment with sophisticated computers to produce multiple cross sectional images of the inside of the body.   These cross sectional images of the area being studied are examined on a computer monitor and can be transferred to a CD.

CT colonography, also known as Virtual Colonoscopy, uses low dose radiation to obtain an internal view of the colon (the large intestine) that is otherwise seen with a more invasive procedure where an endoscope is inserted into the rectum and passed through the entire colon.

How do I Prepare for this Test?  Virtual colonoscopy, as with the conventional colonoscopy, does require bowel preparation.  You will be required to purchase one bottle of Miralax (238 g), along with 4 Dulcolax tablets and a 64 oz. bottle of Gatorade at any pharmacy. 

  • One day before the exam do not eat any solid food. You must drink only clear liquids for breakfast, lunch and dinner.  Clear liquids consist of:  Gatorade, water, coffee or tea without milk, ginger ale, apple juice, broth, popsicles or jello.  Take 2 Dulcolax tablets at 10:00 a.m.  At 4:00 p.m. mix the entire bottle of Miralax (238g) with 64 oz. of Gatorade until completely dissolved.  Drink an 8 oz. glass of water every 10 to 15 minutes until the solution is gone.  Take 2 more Dulcolax tablets at 10:00 p.m. and continue to drink plenty of clear liquids.  The solution will cause you to have repeated loose stools (diarrhea) which is the expected result.  It typically works within 30 minutes but may take up to 3 hours to have an effect.    Do not exceed the recommended Miralax/Dulcolax dose as serious side effects may occur.
  • The day of the exam you must not have anything to eat after midnight.  However, you should take your regular medications with water, unless other instructed by your physician.  If your procedure is scheduled for the afternoon, you may have clear liquids until 10 a.m.  If you are diabetic, take ½ your usual dose of insulin on the morning of the procedure.  If you take a "diabetic pill" you may skip it on the morning of the procedure unless instructed otherwise.  If you have any other questions regarding your medications, please contact your primary care physician.  Please wear comfortable, loose-fitting clothes.  You may be asked to change into a hospital gown for your comfort. Please bring a list of all medications and allergies so we can make a copy for your record and report to the Outpatient Registration Department 15 minutes prior to your scheduled exam time.  Outpatient Registration and Radiology Departments are located on the first floor of both Beverly Hospital and Addison Gilbert Hospitals.  The technologist will greet you in the Radiology department and escort you to the examination room. 

What to Expect During the Virtual Colonoscopy? You may be required to change into a hospital gown for your comfort. The technologist will position you on the table lying on your back on your side.  A small flexible tube will be passed into your rectum.  The Radiologist will gently pump air into the colon using a hand-held squeeze bulb. The purpose of the air is to distend the colon as much as possible to eliminate any folds or wrinkles that might obscure abnormalities in the colon. After the air is inserted, you will be asked to roll onto your back.  The CT table will move you in and out of the scanner asking you to hold your breath.  The table will then move slowly through the scanner. You will hear only slight buzzing, clicking and whirring sounds as the CT scanner revolves around you. The CT Technologist will ask you to roll on your stomach and the scan process will be repeated.  You will be alone in the exam room during the CT scan, unless there are special circumstances. However, the technologist will always be able to see, hear and speak with you at all times.

Testing Time:  The entire examination is usually completed within 15-20 minutes.

Risks of the Test:  Be sure to notify the technologist if there is any chance you may be pregnant or allergic to IV contrast.

Following the Test:  There are no restrictions following this test.  You may return to your regular diet and activities after the scan is complete. 

Results of this Test:  Your ordering physician will receive the results within a few days.  It is important to discuss the results of the exam with your doctor.