Experiments in virtual-endoscopic guidance of bronchoscopy

Transbronchial needle biopsy is a common procedure for early detection of lung cancer. In practice, accurate results are difficult to obtain, since the bronchoscopy procedure requires a blind puncture into a region hidden behind the airway walls. This paper presents an image-guided endoscopy system for procedure preplanning and for guidance during bronchoscopy. Before the bronchoscopy, a 3D CT scan is analyzed to define guidance paths through the major airways to suspect biopsy sites. During subsequent bronchoscopy, the paths give the physician step-by-step guidance to each suspect site location. At a suspect site, a virtual CT image is registered to the bronchoscopic video. Then, the predefined biopsy site, from the prior CT analysis, is rendered onto the registered video. This gives the physician a reference for performing the needle biopsy. This paper focuses on our recent experiments with this system. These experiments involve a rubber phantom model of the human airway tree and in vivo animal tests. The experiments demonstrate the promise of our approach.