Complex wall modeling for hemodynamic simulations of intracranial aneurysms based on histologic images

Abstract

Purpose For the evaluation and rupture risk assessment of intracranial aneurysms, clinical, morphological and hemodynamic parameters are analyzed. The reliability of intracranial hemodynamic simulations strongly depends on the underlying models. Due to the missing information about the intracranial vessel wall, the patient-specific wall thickness is often neglected as well as the specific physiological and pathological properties of the vessel wall. Methods In this work, we present a model for structural simulations with patient-specific wall thickness including different tissue types based on postmortem histologic image data. Images of histologic 2D slices from intracranial aneurysms were manually segmented in nine tissue classes. After virtual inflation, they were combined into 3D models. This approach yields multiple 3D models of the inner and outer wall and different tissue parts as a prerequisite for subsequent simulations. Result We presented a pipeline to generate 3D models of aneurysms with respect to the different tissue textures occurring in the wall. First experiments show that including the variance of the tissue in the structural simulation affect the simulation result. Especially at the interfaces between neighboring tissue classes, the larger influence of stiffer components on the stability equilibrium became obvious. Conclusion The presented approach enables the creation of a geometric model with differentiated wall tissue. This information can be used for different applications, like hemodynamic simulations, to increase the modeling accuracy.

Analysis of Cerebral Aneurysm Wall Tension and Enhancement Using Finite Element Analysis and High-Resolution Vessel Wall Imaging

“…However, this focus on wall tension obviated our ability to study important associations between regional variations in wall stress and wall structure (13,42). Using advanced imaging techniques, Niemann et al (43) have made great advances in using histological samples to create patient specific 3D models of aneurysm walls with heterogeneous structure. Incorporating heterogenous wall properties into a patient specific FEA model noninvasively remains a challenge.…”

Multimodal exploration of the intracranial aneurysm wall

“…Future work could aim at phantom studies, as carried out for validation of the virtual inflation [15]. However, different parts of the aneurysm wall exhibit different elastic properties [33] which might not be realized with a phantom.…”

Rational choice of modelling assumptions for simulation of blood vessel end-to-side anastomosis

“…Still, a number of techniques is available for an approximate study of individual mechanical properties of these layers[9,38,42]. Moreover, for a patient-specific modelling, the angioarchitectonics of the patient's Wilisian circle can be taken into account[31].…”