Determining scope position during colonoscopy without the use of ionizing radiation or magnetic field: The enhanced mapping ability of the NeoGuide endoscopy system

Introduction: Knowledge of the position and shape of the colonoscope could overcome many of the challenges of performing a colonoscopy. Fluoroscopy and magnetic endoscope imaging systems can provide physicians with information on scope shape but are limited by cost and the risk of ionizing radiation. A novel computer-assisted colonoscope was designed to avoid loop formation and thus limit patient discomfort during colonoscopy. The colonoscope utilizes a fully articulated, computer-controlled insertion tube. On manual insertion of the colonoscope, the position and angle of the tip are encoded into a computer algorithm. The system is uniquely capable of creating a real time, three dimensional map of the tip position and insertion tube shape. The map can be displayed on the video monitor to provide the endoscopist with a simultaneous view of the video image of the lumen of the colon, the position of the scope tip, and the three-dimensional shape of the insertion tube.

Methods: In the first part of the study, endoscopists (n=10) were each shown 50 map images generated from the NeoGuide system. The colonoscope was positioned in various locations within a bench top anatomical colon model (Koken, Inc., Tokyo, Japan), and in various loops (e.g. alpha loop, N-sigmoid loop). Endoscopists were asked to determine the position of the scope based solely on the map image. For each image, the scope position as determined by the endoscopist was compared to the actual scope position. In the second part of the study, endoscopists (n=10) were each shown 20 map images and were asked to determine the tip angle based on the map image and the system's novel tip positioning aid. Results were compared to the actual tip position.

Results: In the bench study, endoscopists correctly identified the tip angle and the position of the colonoscope with greater than 90% accuracy. In the clinical trial, real time, three-dimensional map images successfully guided endoscopists performing colonoscopy using the computer-assisted colonoscope.

Conclusions: This study demonstrated that three-dimensional map images generated by the NeoGuide system in a simulated bench top model and in human clinical trials provided accurate information regarding both tip and insertion tube position.