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image/svg+xml Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Closed Access logo, derived from PLoS Open Access logo. This version with transparent background. http://commons.wikimedia.org/wiki/File:Closed_Access_logo_transparent.svg Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Biomedical Signal Pr...arrow_drop_down
image/svg+xml Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao Closed Access logo, derived from PLoS Open Access logo. This version with transparent background. http://commons.wikimedia.org/wiki/File:Closed_Access_logo_transparent.svg Jakob Voss, based on art designer at PLoS, modified by Wikipedia users Nina and Beao
Biomedical Signal Processing and Control
Article . 2014 . Peer-reviewed
License: Elsevier TDM
Data sources: Crossref
DBLP
Article . 2021
Data sources: DBLP
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Multi-frequency inversion in Rayleigh damped Magnetic Resonance Elastography

Authors: Andrii Y. Petrov; Paul David Docherty; Mathieu Sellier; J. Geoffrey Chase;

Multi-frequency inversion in Rayleigh damped Magnetic Resonance Elastography

Abstract

Abstract Magnetic Resonance Elastography (MRE) is able to identify mechanical properties of biological tissues in vivo based on underlying assumptions of the model used for inversion. Models, such as the linearly elastic or viscoelastic (VE), can be used with a single input frequency data and can produce a reasonable estimate of identified parameters associated with mechanical properties. However, more complex models, such as the Rayleigh damping (RD) model, are not identifiable given single frequency data without significant a priori information under certain conditions, thus limiting diagnostic potential. To overcome this limitation, two approaches have been postulated: simultaneous inversion across multiple input frequencies and a parametric approach, when only single frequency data is available. This research compares simultaneous multi-frequency (MF) RD reconstructions using both zero-order and power-law (PL) models with parametric reconstructions for a series of tissue-simulating phantoms, made of tofu and gelatine materials, tested at 4 frequencies (50 Hz, 75 Hz, 100 Hz and 125 Hz) that are commonly applied in clinical MRE examinations. Results indicate that accurate delineation of RD based properties and concomitant damping ratio ( ξ d ) using MF inversion is still a challenging task. Specific results showed that the real shear modulus ( μ R ) can be reconstructed well, while imaginary components representing attenuation ( μ I and ρ I ) had much lower quality. However, overall trends correlate well with the expected higher damping levels within the saturated tofu material compared to stiff gelatine in both phantoms. Depending on the phantom configuration, measured μ R values within the tofu and gelatine materials ranged from 4.77 to 7 kPa and 15.5 to 16.3 kPa, respectively, while damping levels were 11–19% and 3.1–4.3%, as expected. Correlation of the μ R and ξ d values with previously reported result measured by independent mechanical testing and VE based MRE is acceptable, ranging from 48 to 60%. Both PL and zero-order models produced similar qualitative and quantitate results, thus no significant advantage of the PL model was noted to account for dispersion characteristics of these types of materials. The relatively narrow range of frequencies used in this study limited practical identifiability and can thus produce a potentially false assurance of identifiability of the model parameters. We conclude that application of multiple input frequencies over a wide range, as well as selection of an appropriate model that can accurately account for dispersion characteristics of given materials are required for achieving robust practical identifiability of the RD model in time-harmonic MRE.

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
8
Average
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