Colonoscopy exams are important  as they can detect abnormalities in your large intestine. The two main areas of your large intestine are called the colon and the rectum. The colon is on average, 5 to 6 feet long, and makes up the last 5-6 feet of the digestive track.

Since our series on colonoscopy testing, we’ve had several questions come in from patients who were interested in learning more about the virtual colonoscopy testing vs. having a regular colonoscopy performed.

Here are some facts about virtual colonoscopy you should know:

1. During the virtual colonoscopy the procedure will also examine your large intestine in order to look for polyps, or growths that should not be there or other problems or disease processes of the large intestine.   A polyp can be either flat or raised  and is an area of growth on the surface of your large intestine or colon. It is generally more difficult to see flat colon polyps vs. raised colon polyps.

2. In a virtual colonoscopy a computer machine is used which is generally a CT machine or computed tomography scan. Less often, an MRI machine or Magnetic Resonance scan is used to perform the exam.  A series of images is created which then allows the radiologist or the physician interpreting the images to view a three-dimensional view of your large intestine.

3. Bowel preparation is still needed regardless of which type of colonoscopy you have. Meaning that it is important to clean out the intestines prior to having any type of colonoscopy so that your intestines can be viewed clearly without bowel waste obstructing parts of the colon.  Bowel Preparation Tips can be used to make the process of preparing for either type of colonoscopy easier.

4. Differences between regular or conventional colonoscopy vs. virtual colonoscopy: The differences between virtual or regular colonoscopy is basically what type of equipment that is used to view the inside of your intestines or colon. In a regular colonoscopy the physician will use a long lighted flexible tube in order to view the colon. This tube is called a colonscope and the physician will guide this lighted tube into the anus and then slowly progress through the rectum and into all areas of the approximately 5-6 foot colon.  The physician is able to view the images of the colon on a screen as the examination is performed and the physician will be carefully looking at all areas of the intestinal lining to check for any growths or other abnormalities.

During the virtual colonoscopy the machine, either the CT scanner or MRI scanner is used to actually take the pictures or images of the inside of the intestine therefore many patients may automatically come to the conclusion that they would choose to have the virtual colonoscopy rather than the regular colonoscopy because it is less invasive of a procedure.

Yes, it is correct that there are advantages to virtual colonoscopy:

Virtual Colonoscopy Advantages:

* Does not require a colonoscope to be inserted into entire length of the  colon or intestine
* This procedure requires no sedation
* Because no sedation is used, you can return to work or home after the procedure and you do not require a driver to take you home
* Resumption of normal activities immediately after the procedure
* Virtual colonoscopy generally is quicker than a conventional colonoscopy
* If the intestinal area is smaller or narrowed, then a virtual colonoscopy can view the area inside the colon

Disadvantages of a Virtual Colonoscopy

* If any abnormalities are found like polyps which would need to be removed, or if the doctor finds tissue samples that would be recommended to be biopsied, it is not possible to view and remove any tissues during the virtual colonoscopy
* Virtual colonoscopies can only detect polyps that are larger than 10 millimeters. (Or larger than one centimeter or larger as 10 millimeter is equal to 1 cm)  

Now, what you must know as a patient is that statistically, only about 10% of colorectal polyps are considered large  or above 1 cm. You may also read statistics that say these large polyps (the ones that are bigger than 1 centimeter) are the ones most likely to develop  into cancer but you must know if you are choosing virtual colonoscopy, then you must understand that there is a very large number of polyps that the virtual screening will not detect, even though the larger polyps are the ones most likely to develop into cancer.

* So, in the event that  a virtual colonoscopy does detect a larger polyp, you will still need to have another separate procedure which would involved having a conventional colonoscopy in order to remove the larger polyp. Which in most facilities or cases would involve another whole day or days of bowel preparation, scheduling the conventional colonoscopy etc.

* Still requires the bowel preparation and a tube is inserted into your rectum which will allow the radiologist to fill the colon with gas so that the colon can be more easily filmed

* Can be more painful/uncomfortable than a regular colonoscopy because there is no sedation used. Many patients report that the most uncomfortable part of the procedure is the insertion of gas into the colon

* Expense: many insurance companies are not paying for screenings that are virtual

* Virtual colonoscopy is not as widely available as regular conventional colonoscopy exams