A pointwise method for identifying biomechanical heterogeneity of the human gallbladder

Li, W., Bird, N. C. and Luo, X. (2017) A pointwise method for identifying biomechanical heterogeneity of the human gallbladder. Frontiers in Physiology, 8, 176. (doi: 10.3389/fphys.2017.00176) (PMID:28408886) (PMCID:PMC5374253)

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Identifying the heterogeneous biomechanical property of human gallbladder (GB) walls from non-invasive measurements can have clinical significance in patient-specific modelling and acalculous biliary pain diagnosis. In this article, a pointwise method was proposed to measure the heterogeneity of ten samples of human GB during refilling. Three different points, two on the equator of GB body 90o apart and one on the apex of GB fundus, were chosen to represent the typical regions of interest. The stretches at these points were estimated from ultrasound images of the GB during the bile emptying phase based on an analytical model. The model was validated against the experimental data of a lamb GB. The material parameters at the different points were determined inversely by making use of a structure-based anisotropic constitutive model. This anisotropic model yielded much better accuracy when compared to a number of phenomenologically-based constitutive laws, as demonstrated by its significantly reduced least-square errors in stress curve fitting. The results confirmed that the human GB wall material was heterogeneous, particularly towards the apex region. Our study also suggested that non-uniform wall thickness of the GB was important in determining the material parameters, in particular, on the parameters associated with the properties of the matrix and the longitudinal fibres - the difference could be as large as 20-30% compared to that of the uniform thickness model.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Luo, Professor Xiaoyu and Li, Dr Wenguang
Authors: Li, W., Bird, N. C., and Luo, X.
College/School:College of Science and Engineering > School of Engineering > Systems Power and Energy
College of Science and Engineering > School of Mathematics and Statistics > Mathematics
Journal Name:Frontiers in Physiology
Publisher:Frontiers Media
ISSN (Online):1664-042X
Published Online:07 March 2017
Copyright Holders:Copyright © 2017 Li, Bird and Luo
First Published:First published in Frontiers in Physiology 8: 176
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
489101Exploring the Mechanisms of Human Gallbladder PainXiaoyu LuoEngineering & Physical Sciences Research Council (EPSRC)EP/G015651/1M&S - MATHEMATICS
694461EPSRC Centre for Multiscale soft tissue mechanics with application to heart & cancerRaymond OgdenEngineering & Physical Sciences Research Council (EPSRC)EP/N014642/1M&S - MATHEMATICS