Fast interactive CFD evaluation of hemodynamics assisted by RBF mesh morphing and reduced order models: the case of aTAA modelling

Abstract

The medical digital twin is emerging as a viable opportunity to provide patient-specific information useful for treatment, prevention and surgical planning. A bottleneck toward its effective use when computational fluid dynamics (CFD) techniques and tools are adopted for the high fidelity prediction of blood flow, is the significant computing cost required. Reduced order models (ROM) looks to be a promising solution for facing the aforementioned limit. In fact, once ROM data processing is accomplished, the consumption stage can be performed outside the computer-aided engineering software adopted for simulation and, in addition, it could be also implemented on interactive software visualization interfaces that are commonly employed in the medical context. In this paper we demonstrate the soundness of such a concept by numerically investigating the effect of the bulge shape for the ascending thoracic aorta aneurysm case. Radial basis functions (RBF) based mesh morphing enables the implementation of a parametric shape, which is used to build up the ROM framework and data. The final result is an inspection tool capable to visualize, interactively and almost in real-time, the effect of shape parameters on the entire flow field. The approach is first verified considering a morphing action representing the progression from an average healthy patient to an average aneurismatic one (Capellini et al. in Proceedings VII Meeting Italian Chapter of the European Society of Biomechanics (ESB-ITA 2017), 2017; Capellini et al. in J. Biomech. Eng. 140(11):111007-1–111007-10, 2018). Then, a set of shape parameters, suitable to consistently represent a widespread number of possible bulge configurations, are defined and accordingly generated. The concept is showcased taking into account the steady flow field at systolic peak conditions, using ANSYS®Fluent®and its ROM environment for CFD and ROM calculations respectively, and the RBF MorphTM software for shape parametrization.

On the Role and Effects of Uncertainties in Cardiovascular in silico Analyses

“…Additionally, the FSI approach only partially accounts for the vessel movement caused by the heart contraction. To overcome the FSI limitations and to reduce the computation weight, more recently, CFD based on morphing with radial basis functions (RBF) ( 47 – 49 ) were proposed. Another point of discussion is given by the boundary conditions definition.…”

The health digital twin to tackle cardiovascular disease—a review of an emerging interdisciplinary field

“… Compared pre-operative patient-specific simulation of the implant of a custom-made endograft prediction with post-operative outcomes. Numerical analyses; FEA Proof of concept; Precursor of a DT Biancolini et al 2020 Italy 52 High-fidelity surgical planning tool for thoracic aortic aneurysm repair to visualise, interactively and almost in real-time, the effect of various bulge shape parameters. ROM framework to overcome the computing costs required in CFD techniques that are needed for blood flow prediction.…”

A novel formulation for the study of the ascending aortic fluid dynamics with in vivo data

“…Moreover, despite the time discrepancy, the CFD RBF can be considered affordable, as the physiological relevance increases considerably also considering that the mesh motion subroutine used in the simulation software are scripted and can be reused. Probably the routine be optimized even further, decreasing the additional computational effort even more to make more feasible the adoption of this technique in a clinical environment [72]. In summary, a comprehensive evaluation of a novel RBF mesh morphing technique demonstrated that morphing with CT gated dataset can be applied to study patient specific hemodynamics.…”