• Departments & Services
• For Patients
• Research & Trials
• Education
• Find a Doctor

Wireless Capsule Endoscopy at Penn

November/December 2007

Medieval geographers once marked mysterious regions beyond the known world with the words “terra incognita,” a phrase used to describe places unknown. Until recently, the small bowel was one such place, its deep and tortuous folds hidden to most diagnostic methods. With the advent of capsule endoscopy, however, the mysteries of the small bowel are currently disappearing at the rate of 120 images a minute.

Originating in the 1980s, the premise of a tiny, ingestible capsule containing a camera preceded miniaturization technology by almost two decades, a time during which enteroclysis and push enteroscopy came into use for small bowel investigation.

Capsule endoscopy (CE) was introduced in 2001 as an adjunctive tool for the evaluation of small intestinal diseases and disorders, and has since become the procedure of choice for evaluation of the small bowel mucosa. Contained in a indigestible plastic shell, current capsule endoscopes are approximately 11 mm in diameter and 26 mm in length. The capsule's miniature imaging system is comprised of a metal oxide silicon chip camera, six light emitting diodes, two silver oxide batteries and a UHF-band radio telemetry transmitter.

Patients wear an abdominal sensor array and an external data recorder unit capable of processing two images a second. The capsule is swallowed with a glass of water after the patient has fasted for 12 hours and travels through the GI system by natural peristalsis. The capsule is disposable and is excreted naturally. Acquired images have a 1:8 magnification, which is higher than that of conventional endoscopes.

Capsule Endoscopy at Penn
Gastroenterologists David Jaffe, MD, and Nuzhat Ahmad, MD, currently employ capsule endoscopy at the Penn Digestive & Liver Center as an adjunctive diagnostic modality for obscure gastrointestinal bleeding when endoscopy and colonoscopy are unrevealing.

“In the presence of bleeding following negative upper endoscopy and colonoscopy, capsule endoscopy can often preclude a more invasive diagnostic procedure,” says Dr. Jaffe. CE is also used at Penn in patients with suspected Crohn’s disease, and in selected patients with suspected small bowel disease in whom other imaging studies are equivocal.

Clinical Studies
Efficacy studies of CE indicate that the technology demonstrates a substantial diagnostic yield in about two-thirds or more of patients. A meta-analysis of comparative studies performed in 2006 found CE to be comparable to intraoperative endoscopy and superior to push enteroscopy and small bowel radiography for diagnosing small bowel pathology in patients with obscure gastrointestinal bleeding.

In this study, CE was also found to be superior to colonoscopy with ileoscopy, CT enterography, and push enteroscopy for diagnosing nonstricturing small bowel Crohn's disease.

Issues
Many of the concerns linked to first-generation capsule endoscopes have been resolved by improved practice standards and clinical trial findings. At one time, for example, the risks identified with CE included delayed transit in patients with gastroparesis – a concern now addressed by endoscopically placing the capsule beyond the stomach.

Other complications, including small bowel obstruction and pseudoobstruction (~1% incidence in published series) are now typically ruled out by X-ray prior to the procedure. Contraindications to capsule endoscopy include dementia, esophageal stricture, swallowing disorders, small bowel obstruction and defibrillators or pacemakers.

The Future
The FDA recently approved CE for screening and diagnosing patients with esophagitis and Barrett's esophagus. Its exact role in clinical practice remains to be determined. Investigations of CE technology for the diagnosis of small bowel lesions and celiac disease are currently under way. With anticipated advances in technology, the development of a capsule capable of evaluating the colon may also be on the horizon.

	Referring Physicians: To speak with a Penn physician or refer a patient, contact PennHealth through the secure online referral form or by calling 1-800-789-PENN (7366).