Advantages of a virtual colonoscopy:

• This test allows the doctor to view the rectum and the entire colon.
• The test can identify polyps that are smaller than 5 millimeters before they turn into cancer.
• Unlike a colonoscopy:
  • A virtual colonoscopy usually does not require sedation.
  • This is not an invasive procedure. As a result, there is no risk of bleeding or tearing of the lining of the colon.
• Less risk of complications than a colonoscopy.

Disadvantages of a virtual colonoscopy:

• This test may not detect all small polyps, nonpolypoid lesions, and cancers.
• Thorough cleansing of the colon is necessary before the test.
• Polyps cannot be removed during this procedure. If a polyp or nonpolypoid lesion 6 to 9 millimeters in size or larger is detected, a standard colonoscopy will be recommended to remove the polyp or lesion and to perform a biopsy. This usually occurs immediately after the virtual procedure.
• May be expensive.

To prepare for a colonoscopy or virtual colonoscopy, you will need to completely cleanse your intestines so the doctor can clearly see inside. Anything left in the colon ("residue") can mask polyps and cancers during the procedure and thus greatly affect the accuracy of the test. Residue can also prolong the amount of time the test takes which increases the possibility of complications. You may even have to repeat the test (and the cleansing). 

There are several types of preps available to cleanse intestines. Your health care provider will recommend one based on your age, medical history and physician preference. 

• Discuss the available options with your doctor. Think about what is important to you do help make the decision which prep to use. For instance, a prep which includes consuming less liquid may cost you more, even if you have healthinsurance.
• If you are overweight, studies indicate that it takes more to clean your colon. Ask your doctor about increasing the amount of laxative, or starting the cleansing a day early.

Start your prep early. Review the instructions a week before the proedure. For example, you will usually be advised to stop taking the following:

• Iron medications for a week before the test.. Iron can produce a dark black stool which makes the view inside the bowel less clear. Iron preparations contain the words ferric or ferrous in them.
• Aspirin, ibuprofen, naproxen, and other blood-thinning medications for several days before the test. Unless otherwise instructed, continue taking any regularly prescribed medication.
• If any medication you are asked to stop taking was prescribed by another doctor, check with that doctor before stopping. If necessary, he or she may recommend alternative drugs on a temporary basis.

As part of the cleansing, you will likely be on a clear liquid diet for 1 to 3 days before the test. Clear liquids usually cannot be red, blue or purple, due to staining the colon and decreasing visibility. Examples of clear liquids are:

• Clear coffee or tea
• Fat-free bouillon or broth
• Gelatin
• Sports drinks
• Strained fruit juices
• Water
• For additional information about a clear liquid diet, click here.

Some doctors allow patients to eat fiber-free solid foods which includes scrambled eggs, cheese and white bread. If this is of interest to you, be sure to ask your doctor about it.

A few practical tips to make preparation easier follow:

• Toilet paper can be abrasive when used the amount of times needed to clean out your colon. Consider using flushable moist wipes or flushable baby wipes instead. Flushable wipes are available in your local pharmacy. Another alternative is to apply petroleum jelly (Vaseline) or A & D ointment to the skin around your anus after every bowel movement.
• Use a hemorrhoid ointment with a local anesthetic in it before your bottom gets sore (for example, Nupercainal Ointment). The anesthetic produces numbness for a short period of time by stopping nerves from sending pain impulses to the brain. (If you are taking any drugs or supplements, check with your doctor first to be sure there is no negative interaction.)
• Have something to do while on the toilet. For example, a good book or batch of magazines. If you work on a computer, a laptop and a wi-fi connection can allow you to continue to work.

NOTE:

• If you schedule a colonoscopy for the first day of your work week, you do not lose any work time doing the preparation.
• Schedule the colonoscopy for early in the day if possible when the doctor is most alert.
• If when you are ready to leave home for the colonoscopy, if your stoool is still brown,let the nurse know when you arrive. You may be asked to use an enema for further cleaning before the procedure.
• Find out if the place where you will have your colonoscopy has fruit juice available. If not, consider taking your own. It is advisable to drink 6 - 8 ounces of fruit juice after a colonoscopy. (Any drink will do, but fruit juice is better.)
• Arrange to have someone take you home after the colonoscopy. Colonoscopies are done on an outpatient basis (you do not need to stay in a hospital). Outpatients must have someone take them home after the test because they will be impaired and unable to drive.

A colonoscopy is a painless medical procedure that will be performed in the hospital, in an outpatient surgery area or in a doctor's office.

• Before the procedure begins, you will receive a sedative that will at least make you drowsy and may put you to sleep, as well as a pain reliever.
• You will lie on your left side with your knees drawn up toward your chest. A colonoscope is then inserted through the anus. The colonoscope has a small camera attached to a flexible tube.
• While looking at a monitor, the doctor gently moves the colonoscope into the colon. This allows the doctor to examine the walls as the scope travels.
• Air will be inserted through the scope to provide a better view. Suction may be used to remove fluid or stool.
• Because the doctor gets a better view as the colonoscope is pulled back out, a more careful examination is done while the scope is being pulled out.
• Tissue samples may be taken with tiny forceps inserted through the scope.
• Polyps which are shaped like mushrooms may be removed with a wire snare which loops around the polyp. Electricity is then run through the wire to burn or destroy the tissue. This is known as electrocautery: A grounding pad is placed on the body (usually the thigh) before the surgery to protect the patient. Polyps with other shapes will be removed using other tools.
• Photographs of the inside of the colon may be taken.
• Specialized procedures may also be done. For instance, laser therapy which uses intense beams of light to precisely cut, burn, or destroy tissue.

• Unlike most tests, you will know prior to leaving the facility if there is the possibility of cancer in your colon or rectum due to the presence of polyps or other abnormal conditions. There will not be a definitive answer until a sample is tested in a lab by a doctor known as a pathologist. Those test results will be given to your doctor to share with you.  
• You will receive discharge instructions.
• You will be allowed to resume your normal activities.
• You may have some cramping or bloating as a result of the air placed into your colon during the procedure.

NOTE:

• To prevent dehydration, it is advisable to drink 8 to 16 ounces of fruit juice right after the procedure. If fruit juice is not available, any beverage will help with dehydration.
• Eat a light snack as soon as you feel able.  Avoid foods with high fat content. Fats are difficult to digest.

• Unlike most tests, you will know prior to leaving the facility if there is the possibility of cancer in your colon or rectum due to the presence of polyps or other abnormal conditions. There will not be a definitive answer until a sample is tested in a lab by a doctor known as a pathologist. Those test results will be given to your doctor to share with you. 
• You will receive discharge instructions.
• You will be allowed to resume your normal activities.