gms | German Medical Science

Objective: Computational fluid dynamics (CFD) is a powerful tool to investigate aneurysm initiation, growth and rupture. Originating from biomechanical engineering sciences the software solutions are still time consuming and demanding regarding ease of handling. This prevents CFD to come into clinics, where it could promptly provide valuable information for individual treatment decision-making and planning. The goal of this study was to develop a CFD software which is easy to use and provides high-quality results in less than 30 minutes.

Method: A fast semi-automated workflow was developed and established using AMIRA (FEI Visualization Sciences, France) and ANSYS ICEM and CFX (Ansys Inc., USA) for aneurysm preprocessing and visualization. 3D-rotational angiographies of 20 intracranial aneurysms were used. We assumed rigid walls, pulsatile flow and modeled blood as a non-Newtonian fluid and a shear-dependent dynamic viscosity following a Power Law model. The key advantages of the new method are an intuitive 3D-cropping and segmentation tool and a batch-script semi-automated workflow, which makes it easy to handle even for unexperienced users. The results were intensively validated to yield consistent high-quality calculations of streamlines, pressure, wallshear (WSS) and oscillating shear index (OSI).

Results: Using the newly developed workflow, we could gain stable and reliable results in less than half an hour per aneurysm even in complicated anatomies. There was no significant change of hemodynamic parameters like streamlines, pressure, WSS and OSI compared to extensive calculations using high-resolution meshes. The workflow was robust and easy to use even for unexperienced users. Results could be exported to planning and navigation software.

Conclusions: This new method to perform patient-specific CFD-calculations in less than half an hour enables the neurosurgeon to benefit from hemodynamic aspects in the preoperative evaluation of aneurysms. Prospectively this will influence treatment decision-making and planning for the individual patient even in acute cases.