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

Thoracic aortic aneurysms (TAA) are pathological diseases whose biomechanical behavior is often studied through complex computational models to improve clinical diagnosis and decision-making. We explore an approach based on the use of MRI imaging data that enables the implementation of wall displacement, thereby allowing us to propose a patient-specific model while limiting the computational cost of fluid-structure interaction modeling. To this end, i) the displacement of TAA walls is determined using magnetic resonance imaging (MRI) with the appropriate spatio-temporal resolution; ii) this is then implemented in an advanced numerical model; and iii) quantitative velocity comparisons are performed against MRI data. The results show that the 3D displacement of a pathological aorta can be captured within the limits of the best available spatial and temporal resolutions of medical images. Quantitative comparisons on velocity exhibit a mean error deviation that ranges from 7% to 21% for a transverse plane and 26% to 46% for a pseudosagittal plane. Thus using imposed displacements as boundary conditions enables heterogeneity in aortic displacements and root movements to be accounted for the first time in the literature, while reducing computational time compared to fluid-structure interaction modeling and leading to a biomimetic patient-specific model.