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Virtual colonoscopy

What is virtual colonoscopy?

Reliable and non-invasive, virtual colonoscopy is a tomography test (CT scan) that captures 3D images of the inside of the colon and rectum. Colonoscopy gives the radiologist a screen view of the intestinal wall and can accurately navigate through specific areas. It can also assess general abdominal structures. In 5 to 10% of cases, other significant medical conditions are noted (e.g. an ovarian cyst or diverticulitis).

The examination requires insufflation of CO2 (carbon dioxide) to distend the colon using a very small flexible rectal tube. Unless otherwise indicated, an intravenous injection of Hyoscine Butylbromide will be administered. The procedure usually takes 10 to 15 minutes.

Here are a few facts about colorectal cancer

  • The third most common type of cancer in Canada, in both men and women
  • One in 14 men and one in 15 women are at risk of colorectal cancer during their lifetime
  • In Canada, colorectal cancer is the second leading cause of death by cancer
  • The death rate after diagnosis is about 40%
  • Almost 95 percent of cases occur after age 50
  • More than half of cases are diagnosed in people age 70 or older

Remember that early detection can cure nine of every 10 people.

Examination procedure

For the procedure, you will be asked to:

  • Change into a hospital gown and remove your jewellery and all metal objects, which can interfere with image quality
  • Lie comfortably on an examination table

During this time, the technologist will:

  • Insert a small flexible tube into your rectum to inflate your colon. You may experience minor abdominal cramps that will quickly subside.
  • Inject an intestinal relaxant (hyoscine hydrobromide) and take two series of images of 30 seconds each.

Depending on the test prescribed by your health professional, it may be required to inject a contrast agent. We will go through a list of contrast agents with you when you book your appointment. If you think you may be allergic, please let us know.

Preparing for the Examination

A virtual colonoscopy requires full purging of the colon, so you must follow the steps below to prepare.

You can obtain all the following items at no charge from one of our clinics:

  • A bottle (225 ml) of E-Z-Cat 4.6% oral barium solution. Do not dilute the contents of the bottle
  • A Bi-Peg Lyte preparation kit
  • Three (3) Bisacodyl (Dulcolax) tablets
  • A bottle of iodinated contrast medium that you must drink (Gastrografin, 30 ml)

Two (2) days before the examination, please follow this modified diet to properly prepare:

First day of preparation

Liquids allowed:
  • Clear liquids only
  • Clear broth
  • Tea
Solid food allowed:
  • White bread and white pasta
  • A 125 g (4 oz) serving of tuna or skinless white poultry, or two (2) eggs per meal
  • Tomato sauce without vegetables, peels or onions
  • Margarine and oil
  • Liquid meal substitutes without fibre
Avoid:
  • Fruits and vegetables
  • Red meat
  • Nuts
  • Beans
  • Dairy or soy products
  • Liquids containing pulp
  • More than one alcoholic beverage or coffee
  • Any form of grain or whole wheat products or cereals

The day before the examination

The evening before the examination, it is important that you not eat any solid food.

Breakfast
  • Drink at least 250 ml (8 oz) of clear liquid (liquid meal replacement allowed)
  • Before noon, drink at least two (2) 250 ml (8 oz) glasses of clear liquid. Avoid coffee and cola.
Lunch
  • Drink at least 250 ml (8 oz) of clear liquid (liquid meal replacement allowed)
  • Drink half the barium mix
  • Take the three (3) Dulcolax tablets orally (do not chew them)
  • Apply petroleum jelly to your anus to reduce the irritation caused by the diarrhea.
Dinner
  • After 5:00 pm, drink only clear liquids (e.g. chicken broth, water).
  • Drink the rest of the barium mix.
Evening
  • At 6:00 pm, start to drink the Bi-Peg-Lyte preparation (follow the instructions on the package)
  • At 10:00 pm, drink the bottle of Gastrografin (30 ml), unless you are allergic to iodine
  • Then drink a de 250 ml (8 oz) glass of clear liquid
  • Avoid eating or drinking until the examination has been completed
  • You can take your usual medication with a small drink of water.

The morning of the examination

  • You must not eat or drink anything. You can however take your usual medication with a small drink of water
  • You must not smoke or chew gum

A medical prescription is required to perform this examination.
Please note that CT-Scan examinations are not covered by the Régie de l’Assurance Maladie du Québec (RAMQ). However, most group insurance plans cover the costs.

If your healthcare professional has prescribed this examination or if you have any questions, contact us at 1 800 463-7674.