Computerized 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.

How do I prepare?

There are a variety of bowel preparations. Your doctor will discuss with you in advance the specific preparation for your procedure.

In general, however, the following guidelines apply.

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.

Please 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 performed?

Virtual colonoscopies are performed in the Imaging Services Department at Cayuga Medical Center, located at 101 Dates Drive, off NYS Route 96 in Ithaca.