Towards patient-specific hemodynamics of the aorta: A comprehensive CT-guided approach for moving boundary CFD simulations.

Abstract

Numerical simulations play a key role in evaluating the hemodynamics of the thoracic aorta (TA). Common computational fluid dynamics (CFD) methods apply the rigid wall hypothesis, thus disregarding vessel deformation during the cardiac cycle; Fluid-Structure Interaction (FSI) approaches, while accounting for vessel compliance, demand extensive computational resources and rely on assumptions about wall mechanical properties. This study aims to develop a digital twin model of the aorta by implementing an AI-based framework for patient-specific moving boundaries, to be applied in CFD simulations (CFD_MB) of the entire aorta. Starting from multi-phase ECG-gated CT scans, we built models of the TA and left ventricle (LV) at different phases of the cardiac cycle. An in-house non rigid-registration coupled with radial basis functions interpolation, was used to get iso-topological and mapped surface meshes at each phase. From the analysis of the LV volume changes during the cardiac cycle, patient-specific inlet condition was also applied. Results from CFD_MB simulations were compared with those obtained from CFD. The CFD_MB approach accurately captured TA morphological changes during the cardiac cycle, without compromising mesh quality. Differences in the main hemodynamic results were found between the two performed simulations strategies. The CFD_MB approach also modeled the flow waveform shift that occurs along the TA lumen, enabling pulse wave velocity estimation. The implemented pipeline represents a promising method for patient-specific hemodynamic studies, overcoming the limitations of both conventional CFD and FSI simulations.