Chadwick Medical Associates

Virtual Colonoscopy image

Visit our News pages to view a TV news report, and read a newspaper article about Virtual Colonoscopy.

What is Virtual Colonoscopy?

Virtual Colonoscopy is a new diagnostic procedure which allows doctors to detect polyps and cancers of the colon (large bowel). Polyps are small growths in the colon which may become cancerous if not removed. Virtual Colonoscopy is a recently developed technique that uses a CT scanner and computer virtual reality software to look inside the body without having to insert a long tube (Conventional Colonoscopy) into the colon or without having to fill the colon with liquid barium (Barium Enema). Research performed at Boston University and elsewhere has shown that Virtual Colonoscopy is better able to see polyps than Barium Enema and is nearly as accurate as Conventional Colonoscopy for significant polyps. In addition, most patients report that the Virtual Colonoscopy technique is more comfortable than the Barium Enema or Conventional Colonoscopy.

Why is it important?

Colorectal cancer (CRC) is a leading cause of cancer-related death in the United States. In 1999, approximately 140,000 cases of colon cancer were diagnosed in the United States, and 60,000 of these patients will die of the disease. Colon cancer can be prevented if polyps are discovered and removed early. Tumors, masses of abnormal cells, take years to develop. Initially a cell from the colon starts to multiply abnormally and forms a benign (non-cancerous) polyp which can remain harmless for a long time before becoming an aggressive cancer. Polyps, when detected, can be removed preventatively. Nevertheless, individuals at greatest risk of developing colorectal cancer remain largely underscreened. This is due, in part, to poor public awareness and acceptance of current screening techniques.

What are the current methods used to detect polyps?

There are several tests that are used to try to detect polyps. Several government agencies as well as the American Cancer Society recommend that patients undergo a test that allows the doctor to inspect the entire colon at age 50 and then every three to five years. Currently there are two accepted methods for inspecting the entire colon. The Conventional Colonoscopy and the Barium Enema. Other tests like the Flexible Sigmoidoscope or Rigid Sigmoidoscope which can only see a small portion of the large bowel (colon) are considered inferior tests. Although the Barium Enema and Conventional Colonoscopy permit visualization of the entire colon, the sensitivity of the Barium Enema is far from optimal and is uncomfortable for both the patient and examiner. Conventional Colonoscopy is unable to see the entire colon in one out of ten people. In addition, Conventional Colonoscopy may cause an injury to the colon (tear or perforation) in one out of 1500 patients. Medication given into the veins (intravenous sedation) is usually required to make the exam bearable and therefore patients cannot resume normal activities immediately after the test. The introduction of a safe, non-invasive and effective method of detecting colorectal polyps and cancers has obvious appeal and has been the reason researchers at the Center for Virtual Colonoscopy at Boston Medical Center and other sites are pursuing Virtual Colonoscopy.

How is it done?

Victual Colonoscopy uses a standard computed tomography (CT or CAT scan) of the abdomen which allows the radiologist (special physicians with advanced training in x-ray imaging) to create pictures on the computer that look similar to those seen by Conventional Colonoscopy. Patients need a cleansing preparation of their bowel prior to the test. The day of the test, they come to the Radiology Department for a CT scan. The actual Virtual Colonoscopy procedure will begin by having a small flexible rubber tube placed in the rectum, so that air can be introduced. A CT scan is then performed while patients lie comfortably on their back and then on their stomach. The total time required for the study is approximately 10 to 20 minutes. Because sedation is not required, patients are free to leave the CT suite immediately without the need for observation or recovery. Patients can resume normal activities immediately after the procedure and can eat, work, or drive without delay. Doctors (radiologists) analyze the CT data to detect colon polyps or cancers.

What preparation is required for the examination?

1) Clear liquids only the day before the examination.

Important: Drink plenty of water to cleanse the system. Other examples of clear liquids would be: broth, tea (no milk), cranberry juice, apple juice, jello, popsicles, water, ginger ale.

2) At approximately 5:00 pm the day before the exam, you will need to drink a 10 ounce bottle of Magnesium Citrate.

3) At approximately 8:00 pm the day before the exam, you will need to take 2 Dulcolax tablets.

4) On the morning of the examination, (approximately 6:00 to 7:00 am) you will need to take 1 Dulcolax suppository.

5) You must have nothing by mouth on the morning of the exam. However, you may take any prescription medications as usual with a small sip of water.

You can purchase the items needed for this preparation at any pharmacy including CVS, Walgreens, Brooks, etc. Also, most department stores such as K-Mart and Wal-Mart have these available.

Is it painful?

When air is introduced into the colon, some patients experience minimal temporary abdominal cramping, or "gas pains." An intravenous injection of a widely used medication to relax the bowel can also be given to help reduce gas pains, but this is not usually necessary.

How much does it cost, and will my insurance company reimburse me?

Virtual Colonoscopy costs $850, and is not currently reimbursed by most insurance companies, although some may reimburse. As a result, patients will have to assume the cost of the procedure themselves. Payment is required at the time of scheduling.

When and how often do I need to test to screen for polyps?

Current recommendations suggest that patients over 50 years old should be tested every 3 to 5 years. Individuals at high risk should be tested at an earlier age.