The Finite Element Analysis Of Abdominal Aortic Aneurysm

Objective: Using the reverse engineering technology, finite element method analysis and computational fluid dynamics method, a numerical simulation on blood flow for abdominal aortic aneurysm could be established. According to the Von Mises stress distribution on the wall of the abdominal aortic aneurysm, we could investigate the fluid mechanics of the growth,development and rupture of abdominal aortic aneurysm.Methods: The CTA data were obtained by spiral CT scan with contrast and saved in the DICOM3.0 format. Using the MIMICS software, the three-dimensional geometric model of abdominal aortic aneurysm was constructed. Using the finite element software ANSYS to simulate the numerical blood flow under the setted wall boundary conditions, the hemodynamic parameters which related with the growth and rupture of abdominal aortic aneurysm were analyzed.Result: The chart of streamlines and velocity of blood flow in different cardiac periods: After entering the aneurysm, the alternation of the acceleration and deceleration of blood flow was obvious. At the timepoint of 0.04 s, the streamlines within the aneurysm body were sparse, and the color showed light and blue. At the timepoint of 0.27 s, the streamlines in the back part of the aneurysm were intensive and complex, and the color showed dark and red. The chart of the Von Mises stress distribution on the aneurysm wall in different cardiac periods: The main distributed areas showing dark red color of the maximum Von Mises stress located at the back part and outlet of aneurysm.Conclusion: Using the CTA data, the MIMICS software and the finite element software ANSYS method, a precise anatomic three-dimensional geometric model of individual abdominal aortic aneurysm and a finite element model of abdominal aortic aneurysm could be constructed.Using the finite element model of abdominal aortic aneurysm, the velocity vector field, the Von Mises stress and other hemodynamic parameters could be obtained to investigate the hemodynamics of abdominal aortic aneurysm. In the normal cardiac period, the blood flow in abdominal aorta was complicated and the blood flow patterns were influenced by the abdominal aorta morphology. The outlet of the abdominal aortic aneurysm which belonged to the active parts of mechanical properties could be prone to extend. The back part of abdominal aortic aneurysm which was the main distributed areas of the maximum vascular wall Von Mises stress could be prone to rupture.