The biomechanical effects of different membrane layer structures and material constitutive modeling on patient-specific cerebral aneurysms

Abstract

The prevention, control and treatment of cerebral aneurysm (CA) has become a common concern of human society, and by simulating the biomechanical environment of CA using finite element analysis (FEA), the risk of aneurysm rupture can be predicted and evaluated. The target models of the current study are mainly idealized single-layer linear elastic cerebral aneurysm models, which do not take into account the effects of the vessel wall structure, material constitution, and structure of the real CA model on the mechanical parameters. This study proposes a reconstruction method for patient-specific trilaminar CA structural modeling. Using two-way fluid-structure interaction (FSI), we comparatively analyzed the effects of the differences between linear and hyperelastic materials and three-layer and single-layer membrane structures on various hemodynamic parameters of the CA model. It was found that the numerical effects of the different CA membrane structures and material constitution on the stresses and wall deformations were obvious, but does not affect the change in its distribution pattern and had little effect on the blood flow patterns. For the same material constitution, the stress of the three-layer membrane structure were more than 10.1% larger than that of the single-layer membrane structure. For the same membrane structure, the stress of the hyperelastic material were more than 5.4% larger than that of the linear elastic material, and the displacement of the hyperelastic material is smaller than that of the linear elastic material by about 20%. And the maximum value of stress occurred in the media, and the maximum displacement occurred in the intima. In addition, the upper region of the tumor is the maximum rupture risk region for CA, and the neck of the tumor and the bifurcation of the artery are also the sub-rupture risk regions to focus on. This study can provide data support for the selection of model materials for CA simulation and analysis, as well as a theoretical basis for clinical studies and subsequent research methods.

AnXplore: a comprehensive fluid-structure interaction study of 101 intracranial aneurysms

“…Essentially, having both a symmetric parent vessel and inlet profile restrains the complexity of developing aneurysmal flow when compared to the intricate nature of real tortuous arteries. Furthermore, arterial behaviour could be refined both by pre-loading the vessel structure (Bazilevs et al, 2010;Bols et al, 2013) and by employing more sophisticated constitutive modelling, such as the HGO model (Holzapfel et al, 2000) or a multi-layered hyperelastic wall treatment as presented recently by Fan et al (2024). However, the lack of patient-specific data and general guidelines regarding pathological vascular tissue modelling impedes the meaningful prescription of precise wall properties, motivating the use of a Neo-Hookean model in our idealized setting.…”