Real-time interactive virtual endoscopy of the tracheo-bronchial system: influence of CT imaging protocols and observer ability

Objective: to evaluate the influence of different spiral CT examination pro tocols suitable for clinical use on image quality and to assess the observe r dependence in interactive real-time virtual bronchoscopy. Methods and pat ients: real-time perspective volume rendering of the ail-ways in twenty nor mal patients based on four different spiral CT examination protocols was ev aluated by four observers in regard to the order of depictable bronchi. Res ults: best results were obtained using an examination protocol with a small beam collimation and a maximum pitch. Depending on the observer's ability to control the fly path and the orientation of the bronchi with respect to the slice plane up to sixth order bronchi could be depicted, inter-observer variability was up to two branching orders. Conclusion: The performance of virtual bronchoscopy strongly depends on the applied CT examination protoc ol and the observers experience with perspective volume rendering. Both of which have to be taken into account when virtual bronchoscopy is compared w ith fiberoptic bronchoscopy. (C) 2000 Elsevier Science Ireland Ltd. All rig hts reserved.