Non-identifiability of the Rayleigh damping material model in magnetic resonance elastography

Type of content
Journal Article
Thesis discipline
Degree name
Publisher
University of Canterbury. Mechanical Engineering
Journal Title
Journal ISSN
Volume Title
Language
Date
2013
Authors
Petrov, A.
Chase, Geoff
Sellier, M.
Docherty, P.D.
Abstract

Magnetic Resonance Elastography (MRE) is an emerging imaging modality for quantifying soft tissue elasticity deduced from displacement measurements within the tissue obtained by phase sensitive Magnetic Resonance Imaging (MRI) techniques. MRE has potential to detect a range of pathologies, diseases and cancer formations, especially tumors. The mechanical model commonly used in MRE is linear viscoelasticity (VE). An alternative Rayleigh damping (RD) model for soft tissue attenuation is used with a subspace-based nonlinear inversion (SNLI) algorithm to reconstruct viscoelastic properties, energy attenuation mechanisms and concomitant damping behavior of the tissue-simulating phantoms. This research performs a thorough evaluation of the RD model in MRE focusing on unique identification of RD parameters, μIμI and ρIρI.

Results show the non-identifiability of the RD model at a single input frequency based on a structural analysis with a series of supporting experimental phantom results. The estimated real shear modulus values (μRμR) were substantially correct in characterising various material types and correlated well with the expected stiffness contrast of the physical phantoms. However, estimated RD parameters displayed consistent poor reconstruction accuracy leading to unpredictable trends in parameter behaviour. To overcome this issue, two alternative approaches were developed: (1) simultaneous multi-frequency inversion; and (2) parametric-based reconstruction. Overall, the RD model estimates the real shear shear modulus (μRμR) well, but identifying damping parameters (μIμI and ρIρI) is not possible without an alternative approach.

Description
Citation
Petrov, A., Chase, J.G., Sellier, M., Docherty, P.D. (2013) Non-identifiability of the Rayleigh damping material model in magnetic resonance elastography. Mathematical Biosciences, 246(1), pp. 191-201.
Keywords
magnetic resonance elastography, nonlinear inversion, Rayleigh damping, model identifiability, mechanical properties, medical imaging
Ngā upoko tukutuku/Māori subject headings
ANZSRC fields of research
Field of Research::09 - Engineering::0913 - Mechanical Engineering::091399 - Mechanical Engineering not elsewhere classified
Fields of Research::40 - Engineering::4003 - Biomedical engineering::400308 - Medical devices
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