Patient-specific computational fluid dynamics: structured mesh generation from coronary angiography

Abstract

Patient-specific simulations are widely used to investigate the local hemodynamics within realistic morphologies. However, pre-processing and mesh generation are time consuming, operator dependent, and the quality of the resulting mesh is often suboptimal. Therefore, a semi-automatic methodology for patient-specific reconstruction and structured meshing of a left coronary tree from biplane angiography is presented. Seven hexahedral grids have been generated with the new method (50,000-3,200,000 cells) and compared to nine unstructured tetrahedral grids with prismatic boundary layer (150,000-3,100,000 cells). Steady-state blood flow simulation using Computational Fluid Dynamics (CFD) has been used to calculate the Wall Shear Stress (WSS). Our results (99 percentile, area-weighted and local WSS values along a line) demonstrate that hexahedral meshes with respect to tetrahedral/prismatic meshes converge better, and for the same accuracy of the result, six times less cells and 14 times less computational time are required. Hexahedral meshes are superior to tetrahedral/prismatic meshes and should be preferred for the calculation of the WSS.

Full-hexahedral structured meshing for image-based computational vascular modeling

“…As expected, tetrahedral (unstructured) meshes needed much higher resolution than structured meshes to reach mesh independency, with higher computational costs (computational time and memory). Interestingly, the wall shear stress did plateau with progressive refinement of structured meshes but not when unstructured meshes were used [12]. Such differences are also reported in other studies and are attributed to the high numerical diffusion error associated with unstructured meshes [13][14][15].…”

Simulated hemodynamics in human carotid bifurcation based on Doppler ultrasound data

“…The rheological behavior of blood was simulated considering a constant dynamic viscosity value of 0.0035 kg/(m.s), a reasonable assumption for bulk flow metrics [22,23]. Newtonian rheology is reasonable in the context of fluid precision and uncertainties related to boundary conditions [11,[23][24][25]. The volume-filling finite element meshes consisted of nearly 60000 quadratic hexahedral finite elements.…”

High-quality conforming hexahedral meshes of patient-specific abdominal aortic aneurysms including their intraluminal thrombi

“…De Santis et al [3][4][5][6] proposed several methods based on combinations of surface slicing, spline reconstruction and mapping. For example, these authors developed methods to generate conforming, structured hexahedral meshes from triangulated surfaces [5] or from centerline-based synthetic descriptors (centerlines, radii and centerline normals) in combination with block structures [6].…”