Feasibility and Accuracy of Capsule Endoscopy Used as a “Retroeye” for the Diagnosis of Lesions in a Colonic Model

Abstract

Purpose: Despite efforts to modify optics of the colonoscope, there remains a remarkable inability to identify all colonic pathology during colonoscopy. Some lesions can truly “hide” from current technology (proximal haustral folds, curves, etc.). The introduction of the “retroeye” accessory is an attempt to improve the yield of endoscopy in these difficult-to-see anatomical areas. Aim: To assess the feasibility of the capsule endoscopy device used as a “retroeye” to aid in identifying lesions in a colonic model in vitro. Methods: We attached a capsule endoscopy device to the side of an endoscope tip to allow simultaneous, real time, forward (conventional endoscope), and backward (capsule) views of the lumen of a simulated colon model. A colonic model from Boston Scientific was modified to allow a larger luminal diameter and exaggerated folds. A total of 50 “lesions” (pins) of different sizes (2 to 4 mm) and colors were placed (see image), at least 10 of which were truly hidden to the conventional forward viewing endoscope. An experienced endoscopist performed the procedure using only the forward view, followed by simultaneous use of the capsule real time images. Finally, real time images were read collaboratively with a fellow physician. They were unaware of the number and location of the lesions and were instructed to identify all lesions by color and location during the insertion and withdrawal phases of the procedure. The capsule monitor was placed beside the conventional endoscope monitor and projected the images in real time.FigureResults: Both with and without the capsule device attached, an average of 40 lesions (80%) were identified with the conventional forward viewing endoscope. With the aid of the capsule, up to 8 additional lesions were identified, for a cumulative detection rate as high as 96%. Lesions consistently not identified were a small lesion located on a distal haustral fold and a larger lesion found at the corner of a proximal haustral fold. Conclusion: Capsule endoscopy attached to the conventional endoscope enabled the detection of a majority of the lesions which were hidden from the forward view.