Video-based bronchoscope tracking for navigated bronchoscopy

Type: Bachelor Thesis
Student: Benedikt Schultis
Advisor: Nassir Navab
Supervision by: Tobias Reichl, Oliver Kutter

Abstract

Bronchoscopy is a technique for diagnostic and therapeutic procedures in medicine. Thereby a endoscope is inserted in the mouth or nose of the patient and is passed through the trachea in the bronchi. Until now the physicians mostly have to accomplish the examination with only what they see on a monitor and their knowledge of anatomical structures.

Since the bronchus are very complex and have many branches it isn’t easy to stay oriented and so at the expense of the patient the duration of an examination increases. Therefore a system which assists the physicians might be very useful. The main goal is the development of a bronchoscopic navigation system (BNS) that delivers the current position and orientation of the bronchoscope with reasonable visualizations.

In this thesis the tracking process of the bronchoscope based on a 2D-3D registration problem is presented. The 3D-dataset consists of a virtual bronchial tree that is rendered from a given CT-dataset with an iso surface renderer. A flight with a virtual camera through the bronchial tree is simulated to obtain virtual endoscopic images. The 2D dataset are the image frames from the bronchoscopic camera.

Since the pose of the virtual camera in CT space is known the tracking process is reduced to a registration problem where the virtual image which is most similar to the current real image, have to be found. With a given start position and an adequate optimizer and similaritymeasure, this registration step can be performed for each image frame of the real camera and thus we obtain the current position and orientation of the bronchoscope for each frame.

The performance and robustness of our tracking method was tested in experiments and evaluated.

Documents

Benedikt Schultis Video-based Bronchoscope Tracking for Navigated Bronchoscopy Bachelor's Thesis. Technische Universität München, September 2009 (bib)

Literature

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• Mori et al. "New image similarity measures for bronchoscope tracking based on image registration between virtual and real bronchoscopic images". SPIE, 2004, 5369, 165
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• Sugiura et al. "A study on a method for accelerating bronchoscope tracking based on image registration on GPU". 17th Meeting of the Japan Society of Computer Assisted Surgery, 2008