Dynamic simulation and Doppler Ultrasonography validation of blood flow behavior in Abdominal Aortic Aneurysm

Abstract

Criteria for rupture prediction of Abdominal Aortic Aneurysm (AAA) are based only on the diameter of AAA. This method does not consider complex hemodynamic forces exerted on AAA wall. The methodology used in our study combines Computer-Aided Design (CAD) with Computational Fluid Dynamics (CFD). Three-dimensional vascular structures reconstructions were based on Computed Tomography (CT) images and CAD. CFD theory was used for mathematical modeling and simulations. In this way, dynamic behavior of blood flow in bounded three-dimensional space was described. Doppler Ultrasonography (US) was used for model results validation. All simulations were based on medical investigation of 4 patients (male older than 65years) with diagnosed AAA. Good correspondence between computed velocities in AAA and measured values with Doppler US (Patient 1 0.60m·s^-1 versus 0.61m·s^-1, Patient 2 0.80m·s^-1 versus 0.80m·s^-1, Patient 3 0.75m·s^-1 versus 0.78m·s^-1, Patient 4 0.50m·s^-1 versus 0.49m·s^-1) was noticed. The good agreement between measured and simulated velocities validates our methodology and the other data available from simulations (eg. von Misses stress) could be used to provide useful information about the possibility of AAA rupture.

Keywords: Abdominal Aortic Aneurysm (AAA); Blood flow; Computational Fluid Dynamics; Computer Aided Design.