Abdominal aortic aneurysms (AAAs) represent a major cause of death in the U.S. Mathematical and computational models of AAAs are being developed to better predict location and risk of rupture. Most of these models involve three parts: (1) equations to model blood flow, wall stress, or fluid-solid interaction (FSI), (2) reconstruction of vessel geometry from CT or MRI data, (3) finite element analysis to give numerical solutions to the equations.

The ultimate goal of AAA modeling is to provide physicians with a diagnostic tool to help them evaluate risk of rupture. Currently physicians mainly rely on AAA diameter to gauge rupture risk and the need for surgical intervention. However, diameter is not always a reliable indicator of AAA wall stress, and AAA models based on patient-specific data may help physicians better judge when to intervene.

The goal of my project is to develop a method for constructing high-quality hexahedral meshes of AAAs from CT data. These meshes will include iliac bifurcation and be used in future FSI models. I am implementing a method developed by Antiga and Steinman [2004] to automatically decompose a bifurcation into three branches and construct a parameterized representation of the surface. From this parameterized representation, a mapped meshing algorithm will be used to reconstruct a hexahedral mesh of the thrombus volume.

Once a quality finite element mesh of an AAA including bifurcation has been obtained, it can be used in fluid-solid interaction models. These models may provide more accurate results than CFD or structural analyses and provide insight into how the iliac bifurcation affects AAA formation.

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References: Antiga, L. and D. Steinman. 2004. Robust and Objective Decomposition and Mapping of Bifurcating Vessels. IEEE Transactions on Medical Imaging, 23(6):704-713. [pdf]