Virtual Colonoscopy for Colorectal Cancer Screening

A virtual colonoscopy is also called a CT (computed tomography) colonography. This procedure starts with a healthcare provider putting a small, short tube into your anus. This tube inflates your colon so that polyps and other growths can be seen more easily. After that, a CT scanner takes X-rays of your colon and rectum outside the body. A computer puts the X-rays together to create highly detailed pictures of your colon and rectum. These pictures can show where polyps, ulcers, cancer, or other growths are. Sedation and anesthesia are not required for this test.

Colon polyps that are found by virtual colonoscopy cannot be removed during the test. A regular colonoscopy must be done to take them out before they turn into cancer. During a regular colonoscopy, a long, flexible, lighted tube (called a scope) with a tiny camera on the end is put into the rectum and slid up into the colon. This lets the healthcare provider look right at the colon wall and remove any polyps that are found.

Your provider might advise a virtual colonoscopy if you’re unable to have a regular colonoscopy. It may be a good option if you have trouble with anesthesia, breathing problems, issues with swelling or bleeding, or other health concerns.

Even if you are able to have a regular colonoscopy, a virtual colonoscopy has some big benefits:

• It’s more comfortable than a regular colonoscopy.
• You don’t need anesthesia or sedation.
• The scan takes only 10 to 15 minutes.
• It has a lower risk of damaging the large intestine than a regular colonoscopy.
• It can show areas of the large intestine that a regular colonoscopy can’t reach. This may be the case if part of the bowel is very narrow or blocked.

Every procedure has some risks and possible problems. Here are some things to keep in mind if you’re thinking about a virtual colonoscopy:

• Inflating the colon carries a very small risk of causing a tear in your bowel (bowel perforation). But the risk is thought to be far less than with regular colonoscopy.
• Your provider can’t remove polyps and other growths during a virtual colonoscopy. You’ll need to have a regular colonoscopy if they find anything.
• This test can miss some polyps if they are smaller than 10 millimeters. Some of these might be found by a regular colonoscopy.
• This procedure uses X-rays. So there is a small amount of radiation involved. That exposure may slightly raise your risk for cancer. And there may be more risks for people who are pregnant. If you are or could be pregnant, talk with your healthcare provider before the test.
• Virtual colonoscopy may not be covered by your health insurance.
• The test may show problems in other parts of your body (such as your kidneys, liver, ovaries, spleen, or pancreas) which can lead to more tests.

If you have other health issues, there may be different risks. Your healthcare provider can address any concerns before this test.

It’s important to talk with your healthcare provider about any medicines you take before your virtual colonoscopy. This includes:

• Any prescription or over-the-counter medicines
• Vitamins
• Herbs
• Supplements

They should also know about any implanted medical devices you have, such as a pacemaker.

Before having a virtual colonoscopy, you’ll need to do a bowel prep. This is the same prep that’s needed for a regular colonoscopy. This helps empty your colon of stool so that the CT images will be clear. Here's how bowel prep is usually done:

• You may need to limit your diet to clear liquids for 1 or 2 days before the test. These might be water, clear broth, or an electrolyte solution. Follow all directions you get about not eating or drinking before your procedure.
• The day before the test, you may get a strong laxative that will help you empty your colon. This medicine may be in liquid or pill form. You should plan to have many loose or liquid bowel movements. It’s a good idea to stay near a toilet after taking this medicine.
• Just before the procedure, you may get a liquid to drink. This is a contrast medium. It helps coat any stool left inside your colon. This helps the stool and the colon show up more clearly on the X-rays. Talk with your healthcare provider if you’ve had any reactions to contrast in the past.

You can have a virtual colonoscopy wherever a CT scanner is used. In most cases, that’s the radiology department of a hospital or medical center. You will change into a hospital gown before the procedure. Here’s what happens during the test:

• A thin tube will be put about 2 inches in your rectum. It's used to gently inflate your colon with air. You may feel a slight fullness.
• You’ll lie face up on a table that slides into the CT scanner.
• The technologist will leave the room. The CT scanner is run from a separate control room. But you’ll be able to hear and talk with the staff the whole time.
• The table will slowly slide into and through the scanner. You may hear some whirring and clicking noises as it takes pictures.
• You may be asked to lie very still and hold your breath a few seconds several times.
• The scan may be repeated while you lie face down or on your side.
• The table slides out of the scanner when the test is done. The tube is removed from your rectum. Then you will get dressed.

In most cases, you’ll be able to return home without help. You can go back to your normal diet and activities. You may have some gas or cramping right after the test as your body moves the air out of your colon.

You won’t need any medicines or special instructions after the test. Of course, you can talk with your healthcare provider and the radiology staff if you have any questions or concerns.

It's rare to have complications after a virtual colonoscopy. But call your healthcare provider if any of these occur:

• Belly pain
• Fever
• Dizziness
• Blood from your anus
• Blood in your poop

Before you agree to any test or procedure, it’s important to ask:

• Why you are having the test or procedure
• What results to expect and what they mean
• The benefits and risks of the test or procedure
• Any possible side effects or complications
• When and where you will have the test or procedure
• Who will do the test or procedure and what that person’s qualifications are
• What might happen if you don’t have the test or procedure
• Any alternative tests or procedures you could consider
• When and how you will get the results
• Who to call after the test or procedure if you have questions
• How much you'll have to pay for the test or procedure

This may seem like a lot to think about. But a virtual colonoscopy is a safe and effective way to help detect colorectal cancer and other health problems. If you have any concerns or questions, your healthcare provider can help.