Impact of workflow variability on image-based intracranial aneurysm hemodynamics

The interplay between intracranial aneurysm progression and hemodynamics motivates the application of image-based blood flow quantification, providing potential for the identification of high-risk aneurysms, treatment planning, and implant optimization. However, uncertainties arise throughout the interdisciplinary process, from medical imaging to parameter evaluation. This study systematically analyzes uncertainty globally, at individual workflow steps and for potential interactions. Eight factors affecting hemodynamic simulation accuracy - image reconstruction, lumen segmentation, surface smoothing, rheological modeling, inlet/outlet boundary condition, ostium/parent vessel definition - are varied for four representative patient-specific intracranial aneurysms. A total of 1024 transient simulations are evaluated considering twelve hemodynamic parameters to assess marginal and interaction effects. Global uncertainty analysis reveals median absolute deviations of 20.8-25.9 % for maximum velocity (Vmax), 6.8-19.2 % for inflow concentration index (ICI), 10.8-40.8 % for normalized wall shear stress (WSSnorm) and 2.8-48.9 % for low shear area (LSA). Isolated variation demonstrates the highest median deviations for the reconstruction algorithm (Vmax: 4.0-7.0 %, ICI: 6.8-18.9 %, WSSnorm: 13.3-25.1 %, LSA: 2.4-16.0 %), inlet (Vmax: 41.5-52.4 %, ICI: 1.4-8.6 %, WSSnorm: 14.6-28.5 %, LSA: 5.5-93.5 %) and outlet boundary condition (Vmax: 2.0-36.5 %, ICI: 0.6-39.9 %, WSSnorm: 2.4-83.2 %, LSA: 1.9-53.5 %). Lowest median deviations are found for rheological modeling and surface smoothing. Only minor interaction effects are observed between the reconstruction algorithm and inlet definition, as well as between inlet and outlet definitions. This study identifies pivotal variables essential for consistent hemodynamic quantification of intracranial aneurysms. Minimal interaction effects validate the isolated analysis of influencing factors in the majority of cases.