Biomechanics of Abdominal Aortic Aneurysms

Sergio Cornejo and Ender Finol
Carnegie Mellon University, USA

Researchers at Carnegie Mellon’s Vascular Biomechanics and Biofluids Laboratory are studying the biomechanics of ruptured and non-ruptured abdominal aortic aneurysms (AAAs) with non-invasive wall thickness detection in the medical images. Computed tomography scans of patient-specific  AAAs are segmented using an in-house code that estimates the non-uniform wall thickness of the aneurysm and exports masks of the lumen, thrombus and wall. These are then imported into commercial software for reconstruction and meshing of the wall with S3R shells and the thrombus with 10-node tetrahedrals. The mesh is imported into Abaqus for finite element analysis in which the wall and thrombus are modeled with Mooney-Rivlin type materials. The distribution of maximum principal stress at the wall, as shown in the figure, is used to find thresholds of stress by comparison of ruptured vs. Non-ruptured aneurysms.