Capsule endoscopy: better view with less distress. (No Sedation, Insufflation, or Trauma).
Two years ago, a 10-subject study using normal volunteers was presented at the annual Digestive Disease Week. Last year's meeting featured five presentations on the budding technology This year no fewer than 48 presentations favorably compared capsule endoscopy with conventional imaging modalities for diagnosis and monitoring of a wide range of small-bowel disorders, including gastrointestinal bleeding of obscure origin, anemia, Crohn's disease, polyposis, NSAID ulcers, celiac disease, and gastrointestinal disease in children.
"Capsule endoscopy is a breakthrough technology because it enables physicians to look at the entire 30 feet of the small intestine, not just the 4-5 feet that can be visualized with other types of endoscopy," explained Dr. Jonathan Leighton of the Mayo Clinic, Scottsdale, Ariz.
And unlike conventional forms of endoscopy, capsule endoscopy doesn't entail sedation, insufflation, or trauma.
The capsule endoscopy system marketed by Given Imaging Ltd. includes a disposable capsule the size of a large vitamin. It contains a miniature color video camera with wide-angle lens, four LEDs for illumination, a battery, and a transmitter. The device sends radiofrequency signals to a receiver worn on the patient's body Later the data are downloaded to a computer workstation for analysis.
Following a 12-hour fast--no bowel prep--the patient swallows the capsule. It snaps two pictures per second for roughly 8 hours as it works its way passively through the digestive tract while the patient goes about a normal day The physician reviews the resulting video at the computer workstation, using proprietary software that marks sections of the video that have red pixels consistent with a vascular lesion. Triangulation gear specifies where any operable lesions are located.
Given's M2A capsule endoscope received Food and Drug Administration approval last August. Medicare reimburses for the procedure in California and a growing number of other states. Roughly 90% of private insurers now cover the procedure as well, Dr. Leighton said.
"This is only the beginning," Dr. Blair Lewis of Mount Sinai School of Medicine, New York, promised in a state-of-the-art lecture. "The correct way to think of capsule endoscopy is as a diagnostic platform, not just pictures. It's easy to imagine adding motility, pressure, and temperature sensors in the future." Dr. Lewis conducted the pivotal trials that won FDA approval of capsule endoscopy, and is a Given Imaging shareholder and medical advisory board member.
Potential future applications include evaluation of chronic abdominal pain, malabsorption, and irritable bowel syndrome; screening for gastric cancer; surveillance in patients with Barrett's esophagus; localization of small-bowel strictures; and even colonoscopy, he continued.
The best studied application for capsule endoscopy to date is evaluation of patients with obscure CI bleeding and iron-deficiency anemia. Multiple studies have consistently shown that capsule endoscopy identifies a cause of bleeding in about 60% of cases, with an unsuspected small-bowel tumor being found in up to 10% of patients. This diagnostic yield is twice that of push enteroscopy and 12-fold greater than with small-bowel radiographs, Dr. Lewis said.
Although capsule endoscopy isn't specifically approved for pediatric use, it is being used in children, both in private practice and in formal trials. It provides the same superior diagnostic yield as in adults. And it is much better tolerated in children, for whom standard endoscopy is often a particularly difficult and anxiety-provoking procedure.
"To swallow a pill and get information is a wonderful thing," Dr. Lewis said, adding that in the hundreds of capsule endoscopies he has performed he has yet to encounter a patient who had difficulty swallowing the device.
Capsule endoscopy has proved extremely safe, with a 0.5% capsule retention rate in 5,000 cases worldwide. None of the retained capsules has caused obstruction.
The procedure's major drawback is that it takes a physician about an hour to read an exam. That time may be shortened somewhat by refinements in the blood detection and localization software, he said.
Another downside is that in 20% of cases the capsule doesn't reach the colon until after the camera battery has died, so no images are acquired in that area. In the other 80% of cases, however, the capsule spends an hour in the stomach and 4 hours in the small intestine before arriving at the large bowel.
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|Comment:||Capsule endoscopy: better view with less distress. (No Sedation, Insufflation, or Trauma).|
|Publication:||Family Practice News|
|Article Type:||Brief Article|
|Date:||Jul 1, 2002|
|Next Article:||Catheter-free esophageal pH monitoring is now feasible. (Patient-Friendly Device).|