Adding the third dimension--a new tool for constructing 3D models of the airway from 2D bronchoscopic video.

Objective: To develop a new method of using existing bronchoscopic video technology to generate a 3D model of the airway for clinical purposes.

Design: Prospective pilot study with clinical correlation.

Methods: A Storz 7200 bronchoscope was used to obtain video of a standardized tube. The images were then processed using "open source" tools which detected feature points. A three dimensional model was then constructed using these feature points. An in-house 3D image program was then used to compare the 3D model with the standardized tube. Video from a representative airway patient who had previously had a CT of the chest and a bronchoscopic examination was also analyzed using this technique. The 3D model was correlated with CT images to clinically validate this technique.

Setting: Tertiary care hospital.

Patients: One airway patient video was used for clinical validation.

Outcome Measures: (1) Average diameters of the 3D video derived tube model were compared to the actual tube and (2) a cross section of the 3D video derived patient model was compared to the patient CT derived model.

Results: Repeated measures on standardized tubes demonstrated that is it possible to construct an airway model using this novel technique with a less than 5% error. Further, it is possible to construct a 3D model from patient video using existing bronchoscopic technology.

Conclusions: It is possible to extract 3D data from a sequence of 2D images. Further, this 3D model can be used for the purposes of management and planning and is quantitatively accurate and reliable. Initial data suggests that these measurements correlate with actual airway size and may provide a better instrument with which to make surgical decisions.