Improving lesion detection during colonoscopy

Abstract

Colonoscopy has changed since it was first introduced 50 years ago, with glass fibers being replaced by video electronics, the addition of water jets, better illumination, and the use of filters to enhance visual identification of polyps. In spite of these improvements, polyps and tumors of the colon are still overlooked even by the most meticulous examiner. Because missed lesions can develop into cancer, better imaging methods are required. The Third Eye Retroscope is a device that, in conjunction with the video colonoscope, may be able to find virtually all lesions in the colon. This novel device is described here and presents a new way to look into the colon.

Keywords: Retroscope; Third Eye Retroscope; adenoma; colonoscopy; polyps; retroversion; screening; surveillance.

Figure 1

The Third Eye Retroscope automatically turns 180 degrees when extended from the instrument channel of the standard colonoscope. A miniature video camera is housed in its tip and provides a continuous retrograde image during withdrawal through the colon. The light-emitting diode in the bent portion of the instrument provides illumination for the camera. A polarized hood on the tip of the colonoscope prevents the bright light emitted by the retroscope from interfering with the automatic iris of the colonoscope.

Figure 2

In the forward view of the colonoscope, the shaft of the Third Eye Retroscope is visible, as is light from the light-emitting diode (A). The retrograde view from the retroscope reveals the area behind folds and flexures (B). The retroscope looks back at the colonoscope, and the proximal edges and valleys between folds are brightly illuminated by its integrated light source.

Figure 3

The forward view of the colonoscope, looking toward the Third Eye Retroscope, is obscured by the fold (A). However, in the retrograde view, the retroscope is examining the area behind that fold (B) and reveals an adenoma hidden deep behind the fold. This polyp was not visualized by the colonoscope.