Virtual Colonoscopy for Colorectal Cancer
Virtual colonoscopy is a procedure
that is done to look for small polyps or other growths inside your colon. Polyps that grow
on the inside lining of the colon may turn into colon cancer. The American Cancer Society
advises that most men and women at average risk start screening for colon cancer at age 45.
If you have a family history of colon cancer or are at high risk for other reasons, you may
need to have screening even earlier. Virtual colonoscopy every 5 years is one of several
Virtual colonoscopy is also called
CT colonography. CT stands for computed tomography. A CT scanner takes many X-rays of
the colon that are processed by a computer. The computer puts all the X-rays together to
create 3-D images of your colon and rectum.
Reasons for the procedure
Colon cancer is a common cancer in
men and women. The reason for virtual colonoscopy is to find colon cancer at an early
stage when it can be treated more easily. Regular colonoscopy is also used to screen for
colon cancer. A long, flexible, lighted scope and tiny camera a put into the rectum and
up into the colon. This lets the healthcare provider look at the colon directly and
remove any polyps that are there. Colon polyps that are found by virtual colonoscopy can
be removed with regular colonoscopy before they turn into cancer.
Virtual colonoscopy has some
benefits over regular colonoscopy:
It's less uncomfortable and
invasive. It usually doesn't need to include any pain medicine or anesthesia.
It takes less time.
It poses less risk of harming
the large intestine.
It may be used for some
people who are not be able to have regular colonoscopy. In certain cases, it may
be used in people who have problems such as swelling, bleeding, or breathing
It may be able to show areas
of the large intestine that regular colonoscopy can't reach. This may be the case
if part of the intestine is narrowed or blocked.
Risks of the procedure
Every procedure has some risks and
possible problems. For virtual colonoscopy, these include:
A small, short tube is placed
into your anus so that air can be pumped into your colon. This inflates your colon
so that polyps or other growths are more easily seen. Pumping air into the colon
carries a very small risk that it may cause a tear (rupture). But the risk is
thought to be less than with regular colonoscopy.
Polyps or other growths can't
be removed or biopsied with a virtual colonoscopy. You will still need to have a
regular colonoscopy if polyps or other growths are found.
The procedure can miss
some polyps if they are smaller than 10 mm. Some of these might be seen by regular
Unlike most other screening
tests, the test uses X-rays to create pictures of the colon and rectum. The amount
of radiation is small. But it may still raise your risk of cancer slightly. It
could also be dangerous for pregnant women. If you are or could be pregnant, talk
with your healthcare provider before the procedure.
Virtual colonoscopy may not
be covered by health insurance.
You may have other risks, depending
on your health. Be sure to discuss any concerns with your healthcare provider before the
Before the procedure
Tell your healthcare provider about
any medicines you are taking. Before having a colonoscopy, you will need to have a bowel
prep. A bowel prep helps you empty your colon so that the CT images will be clear. Here
is how bowel prep is often done:
Your healthcare provider may
ask you to limit your diet to clear liquids for 1 or 2 days before the procedure.
These might be water, clear broth, or an electrolyte solution.
The day before the procedure,
you will be given a strong laxative in pill or liquid form to help you empty your
colon. You will likely have several loose or liquid bowel movements in the next
Just before the procedure you
may be given a type of liquid to drink. This is called contrast media. It helps
the inside of your colon show up more clearly for the X-rays. Tell your provider
if you've had any reactions to contrast media in the past.
During the procedure
Virtual colonoscopy can be done
wherever a CT scanner is used. In most cases, it's done in the radiology department of a
hospital or medical center. The scan takes only about 10 to 15 minutes. This is what
happens during the test:
The thin tube will be placed
into your rectum. This is used to inflate your colon with air. You may feel a
A radiologist will put you
face up on a table that slides into the CT scanner.
The radiologist will leave
the room. The CT scanner will be operated from a separate control room. You will
be able to hear and talk with the staff.
The table will move into and
through the scanner. You may hear some whirring and clicking noises.
You may be asked to hold your
breath at times.
The scan may need to be
repeated while you lie face down.
After the procedure
In most cases, you should be able
to return home without help. You can go back to your normal diet and activities. You
will likely not need medicines or special instructions. Talk with your healthcare
provider and the radiology staff if you have any questions.
Online Medical Reviewer:
Alteri, Rick, MD
Online Medical Reviewer:
Gersten, Todd, MD
Date Last Reviewed:
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