Summer 03

Gut Check

IU School of Medicine is one of the first medical institutions in the country performing capsule endoscopy, a promising new way to diagnose small intestine disorders.

In the 1966 sci-fi thriller Fantastic Voyage, Raquel Welch and her fellow scientists perform what can only be described as the ultimate in medically invasive procedures to fix a man’s diseased brain. They board a small submarine, are shrunk to the size of invisibility and then injected into a comatose patient. The team speeds past throbbing corpuscles through superhighways of veins and plunges through pulsating traffic jams in the heart and lungs before exiting at the frontal lobe to perform surgery. Oh, Raquel and company have exactly one hour to pull this off before returning to their normal size.

Flash forward to 2003 and a new miniaturized diagnostic medical procedure at the IU School of Medicine called capsule endoscopy. It offers patients a safe, reliable and more comfortable alternative to surgery. The procedure uses the latest in imaging and computer technology to let gastroenterologists probe the sinuous small intestine to determine the source of gastrointestinal bleeding. About 200 capsule endoscopies have been performed at the IU School of Medicine since late 2001 when the Federal Drug Administration approved the procedure.

“Diagnosing gastrointestinal bleeding from the small bowel is a challenge because the small intestine is less accessible than the stomach and colon,” notes Douglas K. Rex, MD, a professor of medicine who specializes in colon, esophageal, stomach and small bowel diseases. “About five percent of gastrointestinal bleeds occur in the small bowel, which can be only partly visualized using colonoscopy or endoscopy. The only alternatives are barium X-rays, which are insensitive, and open surgery, which is invasive and risky.”

Diagnostics

Colonoscopy uses a flexible tube with lenses, a tiny TV camera, and a light at the end. Through fiber-optic technology and a video computer chip, the colonoscope can scan the inside of the colon and transmit images to a video screen. Colonoscopy is used to detect signs of cancer, inflammation, ulcers and colon disorders.
Endoscopy is a visual examination of the upper intestinal tract using a lighted, flexible fiberoptic or video endoscope. It’s used to discover what causes swallowing problems, vomiting, reflux, bleeding and abdominal pain.

The traditional approach to scoping the small intestine involves sedating the patient and pushing the enteroscope through the patient’s mouth, esophagus, stomach and upper portion of the small intestine. The scope can penetrate only about two feet into the twenty-foot-long intestine.

Capsule endoscopy, on the other hand, is far easier on the patient and visualizes the entire small intestine. However, the capsule approach does have two drawbacks, Dr. Rex notes. It cannot be manipulated like the push endoscope nor can it be used to biopsy tissue. Nevertheless, he believes that capsule endoscopy technology may evolve to the point that it becomes available to diagnose most gastrointestinal disorders, such as inflammatory bowel disease, polyps and tumors of the small intestine.

Down the Hatch

To prep for the procedure, the patient fasts from food and water for twelve hours, and adjusts medications if needed. At the doctor’s office, sensors are attached with adhesive sleeves to the patient’s abdomen. The sensors are connected to a data-recording unit worn on the patient’s belt.

Then the patient just says “ah” – and swallows a pill roughly the size of a multivitamin, with a chaser of water. The pill contains a miniature color camera, battery, light source and transmitter. The camera immediately begins to snap images at a rate of two per second and sends them to the recorder.

The medical team then sends the patient on his or her way, whether it’s back to work or any other routine activity. All patients are cautioned to avoid strenuous exercise such as running.

The smoothly contoured pill arrives in the small intestine up to an hour after it is swallowed before making its trip through the snake-like organ. It continues to take photographs as it progresses through the intestine.

Six to eight hours after the capsule was swallowed, the patient returns to the clinic where the recording unit is removed and the information downloaded onto a computer. Analysts closely review the 60,000 recorded images at about twenty frames a second, providing a virtual video of the capsule’s travels.

“The capsule is exceptionally sensitive and is able to detect abnormal blood vessels up to a millimeter (one twenty-fifth of an inch),” Dr. Rex says. “The image quality is very good and reliable.”

Although it’s possible for the pill to get stuck, it’s uncommon and not dangerous for the patient. And what happens to that marvelous, miniature video pill once its fantastic voyage is completed? That’s a matter of nature taking its course.

“We don’t retrieve the capsule; we have all the information we need,” says Dr. Rex. “If a patient wants to keep it as a souvenir that’s fine, but we don’t want it back.”