Assessing the displacement of thoracic aortic aneurysms with magnetic resonance imaging for a biomimetic numerical modeling

Clinical monitoring of thoracic aortic aneurysms (TAA) to determine therapeutic intervention is based on morphological indicators, mainly the maximum diameter and its annual growth rate, which are not sufficiently discriminating. It is therefore necessary to propose studies to predict the evolution of this pathology at an early stage, to make the best decision on the timing of therapeutic intervention. Biomimetic numerical modeling of patients with TAA, coupled with longitudinal studies, would allow to analyse the relevance of certain hemodynamic markers in predicting adverse outcomes. The aim of this study is to develop such biomimetic modeling. To this end, i) the displacement of TAA is determined from magnetic resonance imaging (MRI) images with appropriate spatio-temporal resolutions, ii) then implemented in an advanced numerical model, the results of which iii) are compared with 4D flow MRI data. The results obtained show that i) the 3D patient-specific displacement of pathological aorta can be captured within the limits of the best available medical image spatial and temporal resolution, ii) the use of imposed displacements as boundary conditions allows the aortic heterogeneity of displacements and movements of the aortic root to be accounted while reducing the computational time compared to fluid-structure interaction modeling.