A Methodology for Verifying Abdominal Aortic Aneurysm Wall Stress

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Computational Mechanics

Background:

• Abdominal aortic aneurysm (AAA) diagnosis relies on diameter, but geometric factors influence rupture risk.
• Numerical studies predict AAA wall stress but require experimental validation.
• Current validation methods for AAA numerical models are limited.

Purpose of the Study:

• To present and validate a novel methodology for experimentally verifying numerical wall stress predictions in AAA.
• To assess the accuracy of finite-element analysis (FEA) based wall stress calculations against phantom testing.
• To investigate the statistical correlation between AAA geometric factors and wall stress distribution.

Main Methods:

• Manufactured four AAA phantoms using vacuum casting.
• Acquired phantom geometries via microcomputed tomography (μCT) scanning at various pressures (0, 80, 100, 120 mm Hg).
• Calculated experimental wall stress using a zero-pressure geometry algorithm and numerical wall stress via FEA.

Main Results:

• The proposed methodology demonstrated moderate accuracy with a small average wall stress difference (1.14%).
• Statistically significant correlations were found between wall thickness, mean curvature (MC), and wall stress distribution.
• FEA predictions showed good agreement with experimental wall stress measurements.

Conclusions:

• The developed methodology provides a reliable approach for validating AAA numerical models experimentally.
• Geometric factors, specifically wall thickness and mean curvature, are critical determinants of AAA wall stress.
• This research contributes to improving the clinical application of numerical simulations for AAA management.