A Multiscale Approach for the Coupled Simulation of Blood Flow and Thrombus Formation in Intracranial Aneurysms (original) (raw)
Related papers
Blood flow simulation of intracranial aneurysms
2009
In the course of the research project MEDVIS 3D (www.medvis3d.at), a clinical software application has been developed, capable of 3D reconstruction and visualization of intracranial aneurysms based on 2D medical image data. This system is now being extend ed with the functionality of a physically correct simu lation of blood flow through aneurysms. It shall provide means to estimate rupture risks by calculating the distribution of pressure and shear stresses in the aneurysm, in order to support diagnosis and intervention planning. Due to the time-critical nat ure of the application, we are forced to use the most effi ci nt state-of-the-art numerical methods and technologies . The elasticity equations for vessel walls and Navie rStokes equations for blood flow are discretized via the Finite Element Method (FEM), and the resulting line ar equation systems are handled by an Algebraic Multig rid (AMG) solver. The boundary conditions of both fluid and wall domains are coupled via Fluid-S...
Annals of Biomedical Engineering, 2008
The deposition of intralumenal thrombus in intracranial aneurysms adds a risk of thrombo-embolism over and above that posed by mass effect and rupture. In addition to biochemical factors, hemodynamic factors that are governed by lumenal geometry and blood flow rates likely play an important role in the thrombus formation and deposition process. In this study, patient-specific computational fluid dynamics (CFD) models of blood flow were constructed from MRA data for three patients who had fusiform basilar aneurysms that were thrombus free and then proceeded to develop intralumenal thrombus. In order to determine whether features of the flow fields could suggest which regions had an elevated potential for thrombus deposition, the flow was modeled in the baseline, thrombus-free geometries. Pulsatile flow simulations were carried out using patient-specific inlet flow conditions measured with MR velocimetry. Newtonian and non-Newtonian blood behavior was considered. A strong similarity was found between the intra-aneurysmal regions with CFD-predicted slow, recirculating flows and the regions of thrombus deposition observed in vivo in the follow-up MR studies. In two cases with larger aneurysms, the agreement between the low velocity zones and clotted-off regions improved when non-Newtonian blood behavior was taken into account. A similarity was also found between the calculated low shear stress regions and the regions that were later observed to clot.
Multiscale modeling of intracranial aneurysms: cell signaling, hemodynamics, and remodeling
IEEE transactions on bio-medical engineering, 2011
The genesis, growth, and rupture of intracranial aneurysms (IAs) involve physics at the molecular, cellular, blood vessel, and organ levels that occur over time scales ranging from seconds to years. Comprehensive mathematical modeling of IAs, therefore, requires the description and integration of events across length and time scales that span many orders of magnitude. In this letter, we outline a strategy for mulstiscale modeling of IAs that involves the construction of individual models at each relevant scale and their subsequent combination into an integrative model that captures the overall complexity of IA development. An example of the approach is provided using three models operating at different length and time scales: 1) shear stress induced nitric oxide production; 2) smooth muscle cell apoptosis; and 3) fluid-structure-growth modeling. A computational framework for combining them is presented. We conclude with a discussion of the advantages and challenges of the approach.