Purpose: To improve the diagnosis of pathologic modified airways, a new hybrid visualization system has been developed and tested based on digital image analysis and synthesis of spiral CT as well as the visual simulation of bronchoscopy.

Method/Materials: 20 patients with pathologic modifications of the airways (tumors, lung transplantation) were examined with Spiral-CT. The shape of the airways and the lung tissue is defined by an automatic volume growing method and a following geometric reconstruction by the computation of geometric primitives. This is the basis of a multidimensional display system which visualizes volumes, surfaces and computation results simultaneously. The enable the intuitive and immersive inspection of the airways a virtual reality system, consisting of two graphic engines, a head mounted display system, data gloves and specialized software was integrated.

Results: In 20 cases the extension of the pathologic modification of the airways could be visualized with the virtual bronchoscopy. The user interacts with and manipulates the 3D model of the airways in an intuitive and immersive way. In contrast to previously proposed virtual bronchoscopy systems the described method permits truly interactive navigation, detailed quantitation of anatomic structures and a “see through” the bronchial wall. The system enables a user oriented and fast inspection of the volumetric image data.

Conclusions: To support radiological diagnosis with additional information a virtual bronchoscopy was developed. It enables the immersive and intuitive interaction with 3D Spiral CTs by truly 3D navigation in the airways. The system was tested with 20 Spiral-CTs of bronchial tumors and obstructions and is well suited for the inspection of structures beyond the bronchialtree.