About Your Virtual Colonoscopy

This information will help you prepare for your virtual colonoscopy at Memorial Sloan Kettering (MSK). A virtual colonoscopy is an exam of the colon (large intestine). During this exam hundreds of images are taken using computerized tomography (CT) scanning and a computer. Your doctor will be able to see pictures of your colon, however he or she cannot take any tissue samples (biopsies).

A Week Before Your Procedure

Before a virtual colonoscopy, you’ll need to clean out (empty) your colon. To do this, you’ll need to purchase the following supplies from your pharmacy:

  • 1 (5 mg) tablet of bisacodyl (Dulcolax®). These are usually sold as a box of 10 tablets.
  • 1 (238 gram) bottle of polyethylene glycol (MiraLAX®)
  • 1 (64 ounce) bottle of a clear liquid that is not red, orange, or purple.
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The Day Before Your Procedure

Eating and drinking

Do not eat any solid food the day before your procedure. You will follow a clear liquid diet, which means you can drink only the liquids listed in the chart below. Be sure to drink plenty of fluids other than water, coffee, and tea. You will need the calories from these fluids so that you don’t feel faint.


  Drink Do Not Drink
  • Clear broth or bouillon
  • Clear consommé
  • Clear packaged vegetable, chicken, or beef broth-mix
  • Any products with particles of dried food or seasoning
  • Gelatin (such as Jello®)
  • Flavored ices
  • Anything red, orange, or purple
  • Clear fruit juices, such as white cranberry, white grape, apple
  • Soda, such as 7-Up®, Sprite®, ginger ale, seltzer, Gatorade®
  • Black coffee
  • Tea
  • Juice with pulp
  • Nectars
  • Milk
  • Alcoholic beverages

Prepare your MiraLAX bowel preparation

On the morning before your procedure, mix all 238 grams of MiraLAXwith the 64 ounces of clear liquid until the MiraLAX powder dissolves. Once the MiraLAX is dissolved, you can put the mixture in the refrigerator, if you prefer.

Take your MiraLAX bowel preparation

The MiraLAX bowel preparation will cause frequent bowel movements, so be sure to be near a bathroom the evening before your surgery or procedure.

At 3:00 pm on the day before your procedure, take 1 bisacodyl tablet by mouth with a glass of water.

At 5:00 pm on the day before your procedure, start drinking the MiraLAX bowel preparation.  Drink an 8-ounce glass of the mixture every 15 minutes until the container is empty. When you’re finished drinking the MiraLAX bowel preparation, continue to drink clear liquids until midnight or until you go to bed.

  • Apply petroleum jelly (Vaseline®) or A & D® ointment to the skin around your anus after every bowel movement. This helps prevent irritation.
  • Drink 4 to 6 glasses of clear liquids after you finish the MiraLAX. You may continue to drink clear liquids until midnight, but it is not required.
  • Follow any additional instructions your healthcare provider gave you regarding your surgery or procedure.

Instructions for eating and drinking before your procedure

12 ounces of water

  • Do not eat anything after midnight the night before your procedure. This includes hard candy and gum.
  • Between midnight and up until 2 hours before your scheduled arrival time, you may drink a total of 12 ounces of water (see figure).
  • Starting 2 hours before your scheduled arrival time, do not eat or drink anything. This includes water.
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The Day of Your Procedure

Things to remember

  • Take only the medications your doctor told you to take the morning of your procedure. Take them with a few sips of water.
  • Do not put on any lotion, cream, powder, deodorant, make-up, or perfume.
  • Remove any body piercings and jewelry.
  • Leave all valuables such as credit cards and jewelry at home.
  • If you wear contacts wear your glasses instead.

What to bring with you

  • A list of the medications you take at home
  • Medications for breathing problems (such as inhalers) and/or medications for chest pain
  • A case for your glasses
  • Your Health Care Proxy form if you have completed one

Where to Park

Parking at MSK is available in the garage on East 66th Street between York and First Avenues. To reach the garage, enter East 66th Street from York Avenue. The garage is located about a quarter of a block in from York Avenue, on the right-hand (north) side of the street. There is a pedestrian tunnel that goes from the garage into the hospital. For questions about prices, call 212-639-2338. There are also commercial garages nearby, on East 69th Street between First and Second Avenues and on East 65th Street between First and Second Avenues.

Where to go

Please arrive in the Radiology Suite in the main building of Memorial Sloan Kettering Cancer Center. You may take either the M or the A elevator to the 2nd floor.

What to expect

Once you arrive at the hospital, doctors, nurses, and other staff members will ask you to state and spell your name and date of birth many times. This is for your safety. Patients with the same or similar names may be having procedures on the same day.

After changing into a hospital gown, you will meet your doctor. He or she will explain the procedure, and answer any questions you have. If you take insulin for diabetes, tell your doctor before the procedure starts.

When it’s time for your procedure, you will be brought into the CT scan room and helped onto the scanner bed. Your doctor will give you a small needle under the skin containing glucagon. This is a hormone that normally circulates in your body and is used to relax your colon and prevent cramping. Your doctor will then insert a rubber catheter into your rectum. Air will be put through the tube to expand your colon, then you will have 2 or more low-dose CT scans in different positions.

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After Your Procedure

Once the scan is finished, the tube will be removed. The air will come out naturally, the same as when passing gas. You will be able to get dressed and resume your usual activities after your procedure. Your doctor will have the results in 24 to 48 hours.

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