CT COLONOGRAPHY - AN OPTION FOR THOSE WHO FEAR THE STANDARD COLONOSCOPY

3/4/2003

EAST LANSING, Mich. - Nearly 70 percent of people who should have their colon checked for polyps and potentially cancerous tumors don't do it, something that can literally translate into thousands of deaths every year.

One reason many don't, says Michigan State University radiologist Kelly Ludema, is fear.

"Many people have a fear of the colonoscopy procedure," he said. "And I'm certain that if every one of those 70 percent got a CT colonography every five years, we would be saving lives."

CT colonography, also known as a "virtual colonoscopy," is a relatively new procedure that is more comfortable for the patient, does not require anesthesia and, according to some studies, is as effective as standard colonoscopies.

Offered at MSU's Radiology Center, the procedure also is safer than a standard colonoscopy.

"There can be certain complications with colonoscopies, such as perforating the colon," said Ludema, who is the center's CT section chief. "It's quite rare, but it can happen."

Here's how CT colonography works: Because very little patient preparation is required, there is no need for anesthesia or relaxants. Before the procedure, the patient uses "meal kits" - a low-residue diet - and then takes a liquid drink of magnesium citrate to help cleanse the colon.

The patient lies in a computer tomography (CT) scanner, a doughnut-shaped device quite similar to an MRI machine, in which he or she easily fits. An enema tip, only about an inch long, is inserted into the rectum and the colon is inflated with carbon dioxide gas, making it easier to see inside the nooks and crannies of an organ that can be as long as 10 feet if stretched out.

Then the computer takes over, gathering three-dimensional, computer-generated images from the entire length of the colon. The result is a "virtual" tour of the colon, providing radiologists with a clear image that makes it easier to spot polyps and tumors.

The test takes about a half-hour, Ludema said, and because the patient is not sedated, he or she can return to work, home or usual activities.

The American Cancer Society recommends that those over the age of 50 have their colon screened for cancer, especially if there is a family history of the disease.

It's estimated that 147,500 new cases of colorectal cancer will be diagnosed in 2003. Of those, as many as 57,000 will die from it.

Ludema said the virtual colonoscopy will not replace the standard procedure, in part because standard colonoscopies can remove polyps and other abnormalities. The CT colonography is used only for diagnosis.

"I think what will happen is the two will need each other," he said. "Perhaps 10 years from now everyone will get his or her colon checked with CT. If something is found, the patient will be sent to a gastrointestinal physician who will use the colonoscopy to remove the polyp and determine if it's cancerous."

Polyps are not necessarily cancerous. However, if not diagnosed and treated they can become cancerous.

For more information on Colorectal Cancer Awareness Month, visit the Web site at www.preventcancer.org/colorectal