Characterizing heterogeneous properties of cerebral aneurysms with unknown stress-free geometry – a precursor to in vivo identification

Xuefeng Zhao; Madhavan L Raghavan; Jia Lu

doi:10.1115/1.4003872

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Characterizing heterogeneous properties of cerebral aneurysms with unknown stress-free geometry – a precursor to in vivo identification

Journal article

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Characterizing heterogeneous properties of cerebral aneurysms with unknown stress-free geometry – a precursor to in vivo identification

Xuefeng Zhao, Madhavan L Raghavan and Jia Lu

Journal of biomechanical engineering, Vol.133(5), pp.051008-051008

05/2011

DOI: 10.1115/1.4003872

PMCID: PMC4271810

PMID: 21599099

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Abstract

Knowledge of elastic properties of cerebral aneurysm is crucial for understanding the biomechanical behavior of the lesion. However, characterizing tissue properties using in vivo motion data presents a tremendous challenge. Aside from the limitation of data accuracy, a pressing issue is that the in vivo motion does not expose the stress-free geometry. This is compounded by the nonlinearity, anisotropy, and heterogeneity of the tissue behavior. This article introduces a method for identifying the heterogeneous properties of aneurysm wall tissue under unknown stress-free configuration. In the proposed approach, an accessible configuration is taken as the reference, the unknown stress-free configuration is represented locally by a metric tensor describing the pre-strain from the stress-free configuration to the reference configuration. Material parameters are identified together with the metric tensor point-wisely. The paradigm is tested numerically using a forward-inverse analysis loop. An image-derived sac is considered. The aneurysm tissue is modeled as an eight-ply laminate whose constitutive behavior is described by an anisotropic hyperelastic strain-energy function containing four material parameters. The parameters are assumed to vary continuously in two assigned patterns to represent two types of material heterogeneity. Nine configurations between the diastolic and systolic pressures are generated by forward quasi-static finite element analyses. These configurations are fed to the inverse analysis to delineate the material parameters and the metric tensor. The recovered and the assigned distributions are in good agreement. A forward verification is conducted by comparing the displacement solutions obtained from the recovered and the assigned material parameters at a different pressure. The nodal displacements are found in excellent agreement.

tissue property

Cerebral aneurysms

pointwise identification method

in vivo identification

Details

Title: Subtitle: Characterizing heterogeneous properties of cerebral aneurysms with unknown stress-free geometry – a precursor to in vivo identification
Creators: Xuefeng Zhao - Department of Mechanical and Industrial Engineering, Center for Computer Aided Design The University of Iowa, Iowa City, IA 52242-1527, USA
Madhavan L Raghavan - Department of Biomedical Engineering The University of Iowa, Iowa City, IA 52242, USA
Jia Lu - Department of Mechanical and Industrial Engineering, Center for Computer Aided Design The University of Iowa, Iowa City, IA 52242-1527, USA
Resource Type: Journal article
Publication Details: Journal of biomechanical engineering, Vol.133(5), pp.051008-051008
DOI: 10.1115/1.4003872
PMID: 21599099
PMCID: PMC4271810
NLM abbreviation: J Biomech Eng
ISSN: 0148-0731
eISSN: 1528-8951
Language: English
Date published: 05/2011
Academic Unit: Roy J. Carver Department of Biomedical Engineering; Mechanical Engineering
Record Identifier: 9984064599102771

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