Colon capsule endoscopy

Abstract

The colon capsule endoscopy is designed for direct visualization of the colon through passive propulsion through peristalsis. In contrast to small bowel capsule endoscopy, the colon capsule carries two cameras at each end with a wide viewing angle of 172 degrees. Instead of shooting at a fixed frame rate of 2 frames per second, adaptive frame rate of up to 35 frames per second is activated once the colon capsule is in motion. The battery life is also significantly enhanced to more than 10 hours. Due to the lack of suction and manipulation of the capsule, patients need to undergo a vigorous bowel preparation protocol to ensure an excellent bowel preparation for the better visualization of the colonic mucosa. The performance of the second generation of colon capsule endoscopy has been tested in an international multi-centre prospective trial using optical colonoscopy and segmental unbinding as the reference. It is shown that the sensitivity in identifying subjects with any adenoma (6mm or larger) was 91% and the specificity was 83%. There was however no significant increase in adenoma detection rate for larger adenoma (10mm or larger). Subgroup analysis also showed that the sensitivity for the usually flat and pale looking sessile serrated polyp was 29% only. There are also recent data to suggest that colon capsule endoscopy can be used in the monitoring of mucosal disease activity in patients with inflammatory bowel disease (IBD), particularly in ulcerative colitis and possibility in Crohn's disease. At the present moment, the colon capsule endoscopy is only approved by the Food & Drug Administration of the United States for patients with incomplete colonoscopy. It is anticipated that the indications of colon capsule endoscopy may expand into other diseases soon, particularly on IBD.