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To analyse the dynamic flow in central airways, a workflow has been established which finally enables numerical simulation with simultaneous consideration of natural deformed geometries and inversion of flow direction. A comprehensive description of the radiologic experiments, the segmentation methods and the simulation procedure is given. Finally results gained from simulations in static and dynamic airways are presented and discussed.

Arteriovenous malformations (AVM) are regarded as congenital anomalies consisting of a racemose convolution of pathological vessels which predispose to intercerebral bleeding. The bleeding risk is about 4% per year, with a combined rate of major morbidity and mortality of 2.7% per year (Ondra et al. 1990). Cerebral AVM can be graded according to Spetzler et al. (1986). This system is based on the size of the AVM, localization of draining veins, and eloquence of adjacent brain tissue. It is derived from the potential postoperative complications, such as neurological deficits and mortality. AVMs of grade I or II are easily resectable, while those of grade IV or V are correlated with a high risk of major postoperative neurological deficits. This grading allows comparison with other therapeutic approaches: (a) embolization is very helpful preoperatively in preventing excessive bleeding but does not obliterate a large AVM alone (Fox et al. 1990); (b) stereotactic single high-dose radiotherapy, or “radiosurgery,” shows good results for complete occlusion of the AVM after a latency of approximately 2 years (Engenhart et al. 1989).