Numerical simulation and experimental validation in an exact aortic arch aneurysm model

Abstract

An important medical problem of the non-invasive treatment of brain aneurysm has attracted growing interest. Aneurysm surgery remains dangerous because surgeons have limited knowledge of blood flow patterns and complex 3D geometry of aneurysms. Therefore, a Virtual Aneurysm (VA) research was initiated to make it possible for medical specialists to obtain such detailed information. Recent developments in minimally invasive approach to cerebrovascular diseases include the placement of stents in arteries for treatment of aneurysms. Preliminary clinical observations and experimental studies have shown that intravascular stents traversing the orifice may lead to thrombosis and subsequent occlusion of the aneurysm. The alterations in vessel local hemodynamics due to the introduction of a stent are not yet well understood. In a first step toward such nvestigations the present study relies on comparisons between simulations based on Computational Fluid Dynamics (CFD) and in-situ, Laser Doppler Anemometry measurements in the silicon model of an aortic artery. For this purpose the CFD results are obtained by relying on the well-known industrial software FLUENT 6.3. In order to obtain reproducible results, measurements on an inverse model, in which the position of the blood vessels is stable. The 1:1 model used is made from transparent silicone. In this way, a meaningful comparison with the numerical predictions can be realized. A complex liquid mixture (composed of water, glycerin, xanthan-gum and sodium thiocyanate) has been specifically developed for the present investigation: it shows physical properties very similar to real blood, but leads to a refraction index matched to that of the silicon model. This finally allows accurate velocity measurements within the model and a comparison was made with that of CFD. Detailed comparisons between CFD and experiments will be shown at the Conference along with detailed numerical results of effect of stent on the Aneurysm geometry. © 2009 Springer Berlin Heidelberg.