Axial Tomography (CAT) Scan Virtual Colonoscopy
Imaging (Radiology) Procedures
What is the test?
The CAT scan utilizes X-ray and a
state-of-the-art computer to visualize the large intestine (colon). This diagnostic
procedure, which enables a medical specialist to examine the lining of your
large intestine for any abnormalities, is an important exam for colon cancer
screening. A virtual colonoscopy is performed only when a standard
diagnostic colonoscopy has failed.
do I prepare?
There are a variety of bowel preparations.
Your doctor will discuss with you in advance the specific preparation for your
In general, however, the following
For three days leading up to your
colonoscopy reduce the amount of fiber in your diet by eliminating salads,
bran, fruits and vegetables with skins such as corn, peas, grapes, onions, and
unpeeled apples, nuts, seeds and seed-coated breads. These foods are dense and
may not be adequately flushed out of the digestive tract before the exam.
In addition, discontinue aspirin, iron, and
bulking agents like Metamucil, Citrucel, Psyllium, and FiberCon. If you are
taking Coumadin (Warfarin) or Plavix, ask your doctor for special instructions.
The day before the colonoscopy:
Drink only clear liquids for breakfast,
lunch, and dinner. Solid foods, milk or milk products are not allowed. Clear
liquids include all of the following that are not colored red or purple: strained
fruit juices without pulp, water, clear broth or bouillon (vegetable, chicken,
beef), coffee or tea (without milk or nondairy creamer), Gatorade, carbonated
and noncarbonated soft drinks, Kool-Aide (or other fruit-flavored drinks),
plain Jello (without added fruit or toppings), and ice Popsicles. You should
take nothing by mouth after midnight the evening before your exam.
Your doctor will provide you with detailed
instructions about what to do on the day of your colonoscopy.
plan to arrive 15 minutes before your scheduled exam.
What can I expect
during the procedure?
The purpose of this
exam is to visualize the large intestine (colon), which requires that the colon
be dilated (filled with air). In order to fill the colon with air and keep it
in until the exam is completed, a small tube (Foley catheter) is inserted into
the rectum with a small balloon that will be filled with air. This balloon is
vital to the exam, as letting air escape during the exam can affect the outcome
and possible results of the test. An x-ray will be taken prior to the start of
the test to be sure the prep has cleaned out the colon sufficiently to proceed.
Once it is clear
that the exam can be done and the tube is in place, the radiologist will come
into the room and proceed to pump air slowly into the colon. This may be
uncomfortable to some patients; everyone has different, individual levels of
comfort. It is important to understand that the more air you can tolerate, the
better the dilation will be, which results in better visualization of the colon.
Once the colon is dilated, a series of scans will take place. You will be asked
to lie on your stomach, and then on your back while being scanned.
After the test?
When all the scans
are completed, the balloon will be deflated and the tube removed. You will be
escorted into a restroom. You can expect to will pass air throughout the day
following a virtual colonoscopy. You may resume your normal diet.
How and when will I
get my results?
The rest of the exam
process occurs after you leave the CAT scan room. The radiologist uses the
computer to “virtually fly” through the colon, examining the surface of the inside.
The imaging study results are normally ready for the ordering physician in 2-3
business days. Your referring physician will review the results with you.
Additional time may be required if we are comparing these test results to
previous findings from other hospitals or health care providers.
Where is this test
colonoscopies are performed in the Imaging Services Department at Cayuga
Medical Center, located at 101
Dates Drive, off NYS Route 96 in Ithaca.