Picture Pill Takes 'Fantastic Voyage' Through Small Intestine
INDIANAPOLIS - In the 1966 sci-fi thriller Fantastic Voyage, a medical
team 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 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. 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," notes Douglas K. Rex, MD, 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 the IU School of
Medicine 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 and esophagus and stomach before arriving in the upper
intestine. The scope can penetrate only about two feet into the twenty-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, Dr. Rex notes. It cannot be manipulated
like the push endoscope nor can it biopsy tissue. However, he says 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 and chases 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 was swallowed the patient returns
to the clinic and 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 (1/25 of an inch)," Dr. Rex notes.
"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."
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Media Contact: Joe Stuteville
317-274-7722
jstutevi@iupui.edu
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