What is a Virtual Colonoscopy?

3D Virtual Colonoscopy (or CT Colonography) is the newest method of evaluating the large bowel (colon) to detect for the presence of polyps and cancers. Polyps are small growths off of the wall of the colon that may become cancerous if they are not removed. Polyps less than 10mm in size have a 1% chance of developing into a cancer, while polyps greater than 10mm have a 10% chance of progressing to malignancy. Virtual colonoscopy uses leading edge CT technology and high powered 3-D software to look inside the colon without having to insert a 5 foot long camera in through the rectum (Conventional Colonoscopy).

Multiple research studies performed throughout the United States and Europe have shown that Virtual Colonoscopy is just as accurate as conventional colonoscopy for the detection of significant polyps (> 10mm). In addition, since a CT exam is done to obtain the Virtual Colonoscopy data, the Radiologist will also have a chance to evaluate the other abdominal organs (Liver, Gall Bladder, Spleen, Adrenal Glands, Pancreas and Kidneys) as well as the spine and condition of the blood vessels. This option is obviously not available to the Conventional Colonoscopy operator who can see only the inner walls of the colon.

Virtual Colonoscopy is also more convenient for the patient than Conventional Colonoscopy. In one study of people who underwent both procedures, 71% preferred the Virtual Colonoscopy, stating it to be less painful and requiring a much easier bowel cleansing protocol.(1) These patients selected Virtual Colonoscopy for their future screening exams.

Is Virtual Colonoscopy as good as Conventional Colonoscopy?

YES! And in some cases even better.

Multiple studies have been done to look at the ability of Virtual Colonoscopy to identify clinically significant polyps (those greater than 10mm in size). Each study has found that the accuracy of Virtual Colonoscopy is just as good as Conventional Colonoscopy for significant polyps.

Virtual Colonoscopy can do all of this in a much more comfortable fashion, without the need for sedation or insertion of a 5 foot long camera into the bowel. Because there is no Camera insertion, we do not have the risk of colon perforation which occurs in about 1:1000 people who have Conventional Colonoscopy.

We are always able to visualize the entire colon from one end to the other. In conventional colonoscopy there is about a 10-15% failure rate where they cannot get the camera threaded all the way to the opposite end of the colon.

Automatic tracking of surfaces viewed ensures 100% of the colon surface is viewed!

  

How is Virtual Colonoscopy done?

Virtual colonoscopy uses an advanced type of computed tomography (CT or CAT scan) of the abdomen, which allows our Radiologists to evaluate the entire colon for polyps or masses. 3-dimensional images are also created which are similar in appearance to Conventional Colonoscopy (i.e. Virtual Colonoscopy).

The procedure will begin by having a small flexible rubber tube placed just beyond the opening of the rectum, so that air can be introduced to gently inflate the colon and allow the colon to expand so that the inner walls are not touching.

A CAT scan is performed while patients lie comfortably on their back and then again on their stomach. This allows any pooled fluid in the colon to move from one side to the other, allowing full visualization of the colonic walls. The total time required for the study is approximately 10-20 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 a delay. The Doctor then analyzes the CT data to detect colon polyps or cancers.

Is it painful?

NO. When the air is introduced in the colon some patients experience minimal temporary abdominal cramping or "gas pains". This resolves very quickly as the gas is removed through the tube.

What are some of the Risk Factors for Colon Cancer?

  • Age (Colorectal Cancer usually occurs in people over 50 years old).
  • High Fat / Low Fiber Diet (A common diet in North America).
  • Genetic / Hereditary Disorders (Familial Polyposis, Crohns and Ulcerative Colitis).

What are some of the Warning signs?

  • Bleeding from your rectum or blood in the toilet after a bowel movement.
  • A change in the shape or caliber of your stool.
  • Continuous cramping in the lower stomach.
  • A feeling of discomfort or an urge to have a bowel movement but no ability to pass stool.

Who should get scanned?

The indications for Virtual Colonoscopy include patients that require screening for colonic polyps (the Most Common Reason), patients that have had an incomplete or failed Conventional Colonoscopy or patients that require preoperative assessment of the colon proximal to an occlusive cancer (defined as a tumor that cannot be traversed endoscopically).

The American Cancer Society recommends screening to begin for men and women at 50 years of age. This can be lower if the person has a family history or other concerns. Repeat scanning is appropriate at 3 to 5 year intervals if the colon is free of polyps, or sooner if a small polyp is found.

What are the Advantages of Virtual Colonoscopy?

  • Virtual Colonoscopy is minimally invasive and does not require passage of the endoscope through the colon. Passage of an endoscope is not only painful and invasive, but also carries risks of severe complications such as bleeding or perforation of the colon. Instead of expanding the colon with an endoscopic tube, Virtual Colonoscopy expands the colon comfortably with air.
  • NO rectal camera insertion.
  • Preparation for the exam is somewhat easier than for Conventional Colonoscopy.
  • NO risk of colonic perforation (1:1000 risk noted for Conventional Colonoscopy).
  • It is well tolerated by patients and does not require sedation. Return to business as usual immediately after the exam.
  • It is capable of evaluating the entire colon including any colon upstream from obstructing lesions or anatomy that prevent passage of an endoscope. Conventional Colonoscopy can be incomplete 10 to 20% of the time.
  • Virtual Colonoscopy is significantly less expensive than Conventional Colonoscopy and it’s related necessary services.

Virtual Colonoscopy can also accurately examines the other vital structures in the abdomen and pelvis, which allows problems such as aneurysms, tumors or degenerative changes to be identified. Traditional invasive colonoscopy is limited to only the inner colon surface.

Where can I get additional information regarding this procedure?

Ask your doctor or call our Bridgewater or Edison Centers for more information on this procedure.

To schedule, please call:

  • Bridgewater Imaging Center 908-725-1291
  • Edison Imaging Center 732-548-6800
References
  • 1. Thomeer M, Bielen D, VanBeckevoort D, Dymarkowski S, Gevers A, Rutgeerts P, Hiele M, Van Cutsem E, Marchal G. Patient Acceptance for CT Colonography: What is the Real Issue? European Radiology 12(6): 1410-5, 2002 Jun.
  • 2. Adamek HE, Breer H, Karschkes T, Albert, J, Remann J. MRI in Gastroentereology: Time to say Goodbye to all that Endoscopy? Endoscopy 2000;32(406-10)
  • 3. Thiis-Evensen et al. Incidental Findings in CT Colonography Gut. 1999 Dec;45(6):834-9.

Ask your doctor or call us for more information on any procedure or exam.
To schedule an exam please call our scheduling line at 732-968-5160