Key result
Moderate geometric perturbations in patient-specific aorta models cause single-digit percentage errors in hemodynamic biomarkers.
Why the study?
In numerical simulations of the vascular system, local geometric uncertainties resulting from computed tomography imaging, segmentation, and meshing have not been examined in sufficient detail due to model complexity and computational effort.
Minor geometric variations in patient-specific aortic models have little impact on hemodynamic biomarkers, yielding reasonable engineering accuracy.
Minor geometric variations yield acceptable errors in aortic hemodynamic models; leaves open clinical translation without prospective outcome validation.
In the context of numerical simulations of the vascular system, local geometric uncertainties have not yet been examined in sufficient detail due to model complexity and the associated large numerical effort. Such uncertainties are related to geometric modeling errors resulting from computed tomography imaging, segmentation and meshing. This work presents a methodology to systematically induce local modifications and perform a sufficient number of blood flow simulations to draw statistically relevant conclusions on the most commonly employed quantities of interest, such as flow rates or wall shear stress. The surface of a structured hexahedral mesh of a patient-specific aorta is perturbed by displacement maps defined via Gaussian random fields to stochastically model the local uncertainty of the boundary. Three different cases are studied, with the perturbation magnitude of 0.25, 0.5 and 1 . 0 mm . Valid, locally perturbed meshes are constructed via an elasticity operator that extends surface perturbations into the interior. Otherwise, identical incompressible flow problems are solved on these meshes, taking physiological boundary conditions and Carreau fluid parameters into account. Roughly 300 000 three-dimensional non-stationary blood flow simulations are performed for the three different perturbation cases to estimate the probability distributions of the quantities of interest. Convergence studies justify the spatial resolution of the employed meshes. Overall, the results suggest that moderate geometric perturbations result in reasonable engineering accuracy (relative errors in single-digit percentage range) of the quantities of interest, with higher sensitivity for gradient-related measures, noting that the observed errors are not negligible. • Investigation of the impact of geometric modeling errors on hemodynamic biomarkers. • Structured, hexahedral, higher-order meshes with a Gaussian random field approach for surface perturbation. • Realistic hemodynamics including a patient-specific geometry, boundary conditions and a fluid model. • Analysis of uncertainty in shear-stress-based biomarkers, such as mean pressures and flow rates. • Minor geometric variations have little impact on biomarkers depending on application and desired accuracy.
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Bošnjak et al. (2025) studied Aortic hemodynamics. Geometric perturbations (0.25, 0.5, and 1.0 mm) was evaluated on Hemodynamic biomarkers (flow rates, wall shear stress). Moderate geometric perturbations of patient-specific aorta models resulted in relative errors in the single-digit percentage range for hemodynamic biomarkers.
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