Patient-specific wall stress analysis in cerebral aneurysms using inverse shell model.

Area of Science:

• Biomedical Engineering
• Computational Mechanics
• Medical Imaging

Background:

• Patient-specific vascular structures are often analyzed assuming a stress-free state, which is inaccurate as they are pre-deformed in vivo.
• Traditional stress analysis methods for cerebral aneurysms may lead to inaccuracies due to this assumption.

Purpose of the Study:

• To introduce and demonstrate an inverse approach for stress analysis in patient-specific cerebral aneurysms.
• To improve the accuracy of stress estimations by accounting for the in vivo pre-deformed state.

Main Methods:

• Developed an inverse approach for stress analysis of cerebral aneurysms modeled as nonlinear thin shells.
• Utilized patient-specific lesion surface data from medical images as input, representing the deformed configuration under arterial pressure.
• Solved equilibrium equations to predict wall stress and the unstressed initial configuration.

Main Results:

• The inverse approach predicts wall stress in the deformed configuration and the unstressed initial configuration.
• This method enables wall stress prediction without precise knowledge of wall elastic properties for some lesions.
• In-plane wall stress was found to be insensitive to the material model.

Conclusions:

• The inverse approach offers a more accurate method for stress analysis in cerebral aneurysms compared to traditional methods.
• This technique can provide valuable insights into aneurysm mechanics, potentially without requiring detailed material property data.
• The findings highlight the robustness of in-plane stress estimations against variations in material models.