Chapter 33. Wireless Capsule Endoscopy & Deep Small Bowel Enteroscopy

General Considerations

The first human ingestion of a video capsule endoscope occurred in 1999, and high-quality images from healthy human volunteers were described in 2000. A commercially available capsule was approved by the U.S. Food and Drug Administration (FDA) for use in the United States in August 2001, having been approved for use in Europe earlier that year. Between 2001 and 2007, more than a half million capsule endoscopy studies were performed.

Currently, three video capsules are available for use in the United States. Two are made by Given Imaging (Yoqneam, Israel). One capsule, the PillCam SB2, images the small bowel, while the other, the PillCam ESO2, is designed for imaging of the esophagus. Olympus Medical Systems Corporation (Tokyo, Japan) has also released a small bowel capsule, the EndoCapsule. Two other capsules have been developed and are being studied in clinical trials. The first is a colon capsule for colorectal cancer screening (Given Imaging), and the second is the MiRo capsule (Intro-Medic Co, Ltd, Seoul, South Korea), which uses electric field propagation to transmit the images.

The PillCam SB2 is composed of a complementary metal oxide silicon (CMOS) chip camera, a short focal length lens, six white light-emitting diode (LED) illumination sources, two silver oxide batteries, and a UHF band radio telemetry transmitter. Improvements in the design of CMOS image sensors, application-specific integrated circuits (ASICS) and white LED illumination, along with the development of nontoxic batteries made from silver oxide, allowed for the development of video capsules. The PillCam SB2 and the PillCam ESO2 capsules are 11 × 26 mm and weigh 3.7 g. The images acquired by the capsules have a field of view of 156 degrees, with eightfold magnification and a 1–30 mm depth of view. The capsules have a resolution of 0.1 mm that allows for the visualization of individual villi. The small bowel capsule transmits two 256 × 256 pixel color images per second for a total of 8 hours (~55,000 images), and the esophageal capsule transmits nine images per second from each of its two lenses, for a total of 18 images per second over the course of 20 minutes (~22,000 images). The EndoCapsule is similar to the PillCam SB2, but instead of a CMOS chip it has a charge-coupled device.

Indications

The indications for small bowel and esophageal capsule endoscopy are ...