An Optimized Numerical Simulation Approach To Stent Implantation For Interventional Therapy Of Intracranial Aneurysm Using Medical Images

Intracranial aneurysm is a vascular disorder in which a blood vessel in the brain shows a balloon-like swelling of the wall, due to a weakening of the vessel wall layers, with a propensity for rupture. Moreover, the rupture of aneurysms will lead to catastrophic complications of high mortality and morbidity, such as subarachnoid hemorrhage. Early diagnosis and treatment of intracranial aneurysm have an important clinical significance. Intracranial stents are becoming increasingly a useful option in the treatment of intracranial aneurysms(Intracranial Aneurysms, IAs). It has also been reported that the factors, such as vascular geometry, stent configuration, the porosity of stent, and the placement can affect the aneurysm therapy. Image simulation of the releasing stent configuration together with computational fluid dynamics(Computational Fluid Dynamics, CFD) simulation prior to intervention will help surgeons optimize intervention scheme. This paper proposed a fast virtual stenting of IAs based on active contour model(Active Contour Model, ACM) which was able to virtually release stents within any patient-specific shaped vessel and aneurysm models built on real medical image data. Then the parent vessel centerline was extracted using application software VMTK. The initial virtual stent contour produced from the initial stent method was placed along the vessel centerline path. An energy function based on ACM algorithm was constructed to drive the deformation of the initial stent contour. Besides, we created a new termination criterion for virtual stent expanding, which facilitate the close fitting of the expansion stent mesh to the vessel surface applying elastic collision detection theory. At last, the CFD analysis was performed to explore the influence of stents deployment on the hemodynamic parameters of IAs. We built a kind of integrated virtual stenting workflow using patient-specific aneurysm models for Silk stent and Enterprise stent. We then performed CFD simulation on the two kinds of virtually stented aneurysms and calculated the hemodynamics. Our simulation results showed that the blood flow was limited to the aneurysm due to stent implantation. Thus the inflow into aneurysm was reduced and the flow velocity at the aneurysm neck was decreased. Furthermore, the results indicated a reduction of the WSS(Wall Shear Stress, WSS) owing to the presence of the virtual stenting. And we found that the Silk stent could induce much more reduction in haemodynamic parameters of aneurysm than the Enterprise stent. The experiment results of the virtual stenting and the corresponding CFD simulations exhibited the efficacy and accuracy of the ACM based method, which are valuable to intervention scheme selection and therapy plan confirmation.