AneuPy: An open source Python tool for creating simulation-ready geometries of abdominal aortic aneurysms

TL;DR

Abdominal aortic aneurysms (AAAs) present a substantial rupture risk, and accurate biomechanical risk predictions rely on realistic geometry. The authors introduce AneuPy, an open-source Python tool built on the SALOME geometry module that can generate both idealized and patient-specific, simulation-ready AAA geometries, including wall layers and intraluminal thrombus (ILT). The workflow provides automation from minimal input data with parametric descriptors such as $\beta = r/R$, $\gamma = D_{max}/L_{AAA}$, and $\chi = D_{max}/D_{proximal neck}$, enabling ready export to formats like IGES, STEP, and VTK for FEA/CFD/FSI analyses. By delivering a scriptable, reproducible pipeline from centerline data to fully defined geometries, AneuPy aims to enhance the efficiency and fidelity of biomechanical studies and patient-specific rupture risk predictions in AAAs.

Abstract

Abdominal aortic aneurysms (AAAs) are localized dilatations of the abdominal aorta that can lead to life-threatening rupture if left untreated. AAAs primarily affect older individuals, with high mortality rates following rupture, so early diagnosis and risk assessment are critical. The geometrical characteristics of an AAA, such as its maximum diameter, asymmetry, and wall thickness, are extremely significant in biomechanical models for the assessment of rupture risk. Despite the growing use of computational modeling for AAA investigation, there is a notable gap in accessible, open-source software capable of generating simulation-ready geometries for biomechanical and hemodynamic simulations. To address this gap, we introduce \textbf{AneuPy}, an open-source Python-based tool designed to create both idealized and patient-specific AAA geometric models. \textbf{AneuPy} is a fast and automated approach for generating aneurysm geometries from minimal input data, allowing for extensive parameter customization. By automating the creation of simulation-ready geometries for finite element analysis (FEA), computational fluid dynamics (CFD), or fluid-structure interaction (FSI) models, \textbf{AneuPy} can facilitate research in AAA and improve patient-specific risk prediction.

Figures (5)

• Figure 1: Typical workflow for generating AAA Geometries using AneuPy'sPatient_specific.py module. The process begins with the importation of the aneurysm's centerline as XYZ coordinates. This raw centerline data is then smoothed using cubic B-splines to reduce noise. Points of interest (POIs) are extracted from the smoothed centerline for detailed analysis. Using SALOME's MakeInterpol() function, a B-spline curve is created. At each POI, a cross-sectional plane is established using the Section class. Subsequently, local radius and ILT thickness are interpolated from the data, and a circle is constructed on each cross-sectional plane. NURBS are interpolated over these circle sections to create a continuous shell along the aneurysm with the Shell class. This shell is then converted into a solid model using add_solid_from_shell(). Finally, boolean operations are performed with add_solid_from_cut() to subtract the ILT volume from the AAA model, generating the final geometries.
• Figure 2: Parameterization of an abdominal aortic aneurysm. Here, $L_{\text{AAA}}$ represents the aneurysm length, $D_{\text{max}}$ is the maximum diameter of the aneurysm, and $D_{\text{proximal neck}}$ and $D_{\text{distal neck}}$ are the diameters of the non-dilated aorta at the proximal and distal necks, respectively. On the right, we show a schematic illustration of the midsection at the location of the maximum diameter, where $r$ and $R$ are the radii measured from the center of the undilated portion to the posterior and anterior walls, respectively.
• Figure 3: Idealized geometries generated with AneuPy's Idealized_automatic.py module. (A) Healthy aorta. (B) Fusiform aneurysm. (C) Saccular aneurysm. (D) Cross sections of a saccular aneurysm without Intra Luminal Thrombus (ILT). (D) Cross sections of a saccular aneurysm with ILT, where the false and true lumen are clearly differentiated. The dotted lines superimposed on the circular cross sections indicate the non-dilated lumen.
• Figure 4: Patient-specific geometries generated with AneuPy's Patient_specific.py module. (A-B) Wall radius and ILT thickness vs. normalized length taken from kontopodis2013changeskontopodis2020aneurysm. (C-D) 3D view of generated aneurysms. (E-F) 3D view of cross sections aligned along centerline used to interpolate the outer surfaces. (G-H) Vertical cross section of the aneurysms, where the lumen and the ILT are clearly differentiated. We also show the centerline with a dotted line.
• Figure 5: Screenshot of SALOME's Geometry module user-friendly interface, where users can open the .hdf study files to inspect the generated geometric entities. This feature allows users to visually verify the created geometries before proceeding with further processing or simulations.