Robust colonoscope tracking method for colon deformations utilizing coarse-to-fine correspondence findings

Area of Science:

• Medical imaging and instrumentation
• Gastroenterology
• Robotics and navigation

Background:

• CT colonography identifies polyps for colonoscopic polypectomy.
• Accurate colonoscope navigation is crucial for effective polyp removal.
• Existing tracking methods fail due to colon deformation during insertion.

Purpose of the Study:

• To develop a colonoscope tracking method robust against colon deformations.
• To enable precise navigation for colonoscopic polypectomy procedures.

Main Methods:

• Generating a colon centerline from CT data and a colonoscope shape line using electromagnetic sensors.
• Employing landmark-based coarse and length-based fine correspondence finding for accurate point matching.
• Utilizing previously recorded line lengths to overcome tracking failures caused by colon deformation.

Main Results:

• The proposed method achieved tracking errors below 50 mm in most trials with a colon phantom.
• Gastroenterologists deemed these tracking errors acceptable for polyp visualization and removal.
• Successful tracking was demonstrated even in the presence of significant colon deformation.

Conclusions:

• A novel colonoscope tracking method robust to colon deformation has been developed.
• The method's design accounts for colon deformations, ensuring reliable tip position tracking.
• This advancement supports safer and more effective colonoscopic polypectomy procedures.