Development of computer-based simulator for catheter navigation in blood vessels (1st report, evaluation of fundamental parameters of guidewire and blood vessel)

We have developed catheter simulation system in blood vessels for surgical planning and intra-operative assistance. In this study, we evaluated the effect of the fundamental parameters of the guidewire and blood vessel models for the simulation system. The model of the guidewire was constructed with viscoelastic springs and segments to avoid complicated mathematical procedures as the dynamic deformation of a flexible structure. The vessel is an elastic circular cylinder, whose shape is defined by the centerline and the radii. Collisions between the guidewire and the vessel are calculated and the contact forces are determined according to the stiffness, damping and friction of the vessel wall. Using these models, the trajectory of the guidewire tip and the reaction force were calculated. When friction coefficient between the guidewire and the vessel is large, the guidewire tip vibrates. When deformation property of the vessel is changed, the trajectory of guidewire tip also changes. Bending of the guidewire tip decreases the reaction force at bending points of the vessel. When the guidewire becomes stiffer, the deformation of the vessel becomes large. These findings should facilitate determination of the parameters of the simulation system.