The course and the success of an endovascular intervention can be influenced by the choice of the guidewire and primary by its ability to access to the lesion. The simulation of catheterism in complex vasculature is of main interest to aid the surgery planning. The overall objective of the simulation is to improve the choice of guidewire (with the simulation of its intrinsic features: torque, shape, rigidity, elasticity) as well as its navigation within patient specific vasculature. We propose a new approach for the simulation of guidewire navigation. It is based on: (i) the modeling of guidewire using "multi-body" approach and the representation of its internal characteristics, (ii) the modeling of artery as a surface mesh, (iii) the simulation of the interactions of the guidewire with its environment (artery and clinician). In this study, strength and elasticity of the guidewire are modeled. Only the "push" action performed by the clinician is considered. The global behavior of the guidewire is simulated by means of retraction and relaxation processes. To interact with the artery walls, methods based on the graphics hardware have been developed (i) to detect the collisions between the guidewire and the artery walls (ii) to find the direction of the retraction process which define the local reaction of the guidewire. All these methods have been tested in a qualitative validation on a patient vasculature.
Transfemoral Endovascular Aneurysm Management, the less invasive treatment of Aortic Abdominal Aneurysms (AAA), is a highly specialized procedure, using advanced devices and requiring a high degree of clinical expertise. There is a great need for a navigation guidance system able to make this procedure safer and more precise. In this context of computer-assisted minimally invasive interventional procedures, we propose a new framework based on the cooperation between the real environment where the intervention takes place and a patient-specific virtual environment, which contains a virtual operating room including a C-arm model as well as the 3D preoperative patient data. This approach aims to deal with the problem of lack of knowledge about soft tissue behavior by better exploiting available information before and during the intervention through a cooperative approach. In order to assist the TEAM procedure in standard interventional conditions, we applied this framework to design a 3D navigation guidance system, which has been successfully used during three TEAM interventions in the operating room. Intra-operatively, anatomical feature-based 2D/3D registration between a single 2D fluoroscopic view, reproduced from the pose planned in the virtual environment, and the preoperative CT volume, is performed by means of a chamfer distance map. The 3D localization of the endovascular devices (sheath, guide wire, prosthesis) tracked either interactively or automatically on 2D sequences, is constrained to either the 3D vascular tree or a 3D device model. Moreover, we propose a first solution to take into account the tissue deformations during this particular intervention and to update the virtual environment with the intraoperative data.