Picture pill takes ‘Fantastic Voyage’ through small intestine

By Joe Stuteville

They board a small submarine, are shrunk to the size of invisibility and then are injected into the comatose patient. The team travels past throbbing corpuscles, speeds through superhighways of veins and plunges through pulsating traffic jams in the heart and lungs before they take the exit ramp to the frontal lobe to perform surgery.

Flash forward to 2003 and a new miniaturized diagnostic medical procedure has become a reality at the IU School of Medicine (IUSM). It’s called capsule endoscopy and offers patients a safe and reliable alternative to surgery. The procedure uses the latest in imaging and computer technology so that gastroenterologists can probe the sinuous small intestine to determine the source of obscure gastrointestinal bleeding.

“Diagnosing gastrointestinal bleeding from the small bowel is a challenge because the small intestine is less accessible than the stomach and colon,” noted Dr. Douglas Rex, 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.”

About 200 capsule endoscopies have been performed at IUSM since late 2001, when the Federal Drug Administration gave its blessing to the procedure.

The capsule endoscopy also may be useful for detecting inflammatory bowel disease, polyps and tumors of the small intestine. And it’s easier on the patient compared to current approaches of viewing the small intestine. Typically, a patient is sedated and the enteroscope is pushed through the patient’s mouth, esophagus and stomach before arriving in the upper intestine. The scope can penetrate only about two feet into the 20-foot-long intestine.

People who have had traditional colonoscopy or endoscopy exams can appreciate the less invasive nature of capsule endoscopy, which does not require anesthesia or long tubes traveling through the colon or down the throat.

The capsule approach has two drawbacks, Rex noted. It cannot be manipulated like the push endoscope nor can it biopsy tissue. However, he said he believes that as capsule endoscopy technology evolves, it might one day be available to diagnose most gastrointestinal disorders.

The procedure begins like many diagnostic procedures. The patient reports to the doctor’s office after fasting from water and food for 12 hours. 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 chasing it with water. The pill contains a miniature color camera, battery, light source and a 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 is swallowed, the patient returns to the clinic, the recording unit is removed and the information downloaded onto a computer. Analysts closely review the 60,000 recorded images at about 20 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 (1/25 of an inch),” Rex noted. “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,” said Rex. “If a patient wants to keep it as a souvenir, that’s fine, but we don’t want it back.”