Viscoelastic properties of liver measured by oscillatory rheometry and multifrequency magnetic resonance elastography

Klatt, Dieter; Friedrich, Christian; Korth, Yasmin; Vogt, Robert; Braun, Jürgen; Sack, Ingolf

doi:10.3233/bir-2010-0565

Cited by 91 publications

(77 citation statements)

References 14 publications

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“…Given the metabolic nature of liver tissues, it is expected that the mechanical and structural properties of the samples postmortem not only varied across the tissue samples, but was also different from the liver tissue in vivo . Nevertheless, ex vivo findings on mechanical and structural properties of liver under healthy and pathological conditions have widely been used to better understand the disease mechanisms and in vivo findings (Brunon et al 2010; Gao et al 2010; Klatt et al 2010; Chatelin et al 2011; Huang et al 2011; DeWall et al 2012). The primary objective of this study was to obtain the tissue mechanical property contrast between the lesion and the background.…”

Section: Discussionmentioning

confidence: 99%

“…Gao et al have performed shear, compression and tensile mechanical testing on porcine livers ex vivo and used the experimental data to develop energy-based constitutive models of liver tissue (Gao et al 2010). An advanced shear rheometry instrument has been used to measure the shear and loss moduli of bovine liver ex vivo under a high frequency range of 25-62.5 Hz , and have been compared against those obtained on human liver using MRE in vivo (Klatt et al 2010). Brunon et al has tested the failure of porcine and post-mortem human livers using tensile testing ex vivo (Brunon et al 2010).…”

Section: Introductionmentioning

confidence: 99%

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Ex Vivo Characterization of Canine Liver Tissue Viscoelasticity after High-Intensity Focused Ultrasound Ablation

Shahmirzadi

Hou

Chen

et al. 2014

Ultrasound in Medicine & Biology

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Elasticity imaging has shown great promise in detecting High Intensity Focused Ultrasound (HIFU) lesions based on their distinct biomechanical properties. However, quantitative mechanical properties of the tissue and the optimal intensity for obtaining the best contrast parameters remain scarce. In this study, fresh canine livers were ablated using combinations of ISPTA intensities of 5.55, 7.16 and 9.07 kW/cm2 and time durations of 10 and 30 s ex vivo; leading to six groups of ablated tissues. Biopsy samples were then interrogated using dynamic shear mechanical testing within the range of 0.1-10 Hz to characterize the post-ablation tissue viscoelastic properties. All mechanical parameters were found to be frequency dependent. Compared to the unablated cases, all six groups of ablated tissues showed statistically-significant higher complex shear modulus and shear viscosity. However, among the ablated groups, both complex shear modulus and shear viscosity were found to monotonically increase in groups 1-4 (5.55 kW/cm2 for 10 s, 7.16 kW/cm2 for 10 s, 9.07 kW/cm2 & 10 s, and 5.55 kW/cm2 & 30 s, respectively), but decrease in groups 5 and 6 (7.16 kW/cm2 for 30 s, and 9.07 kW/cm2 for 30 s, respectively). For groups 5 and 6, the temperature was expected to exceed the boiling point, and therefore, the decreased stiffening could be due to the compromised integrity of the tissue microstructure. Future studies are needed to estimate the tissue mechanical properties in vivo and perform real-time monitoring of tissue alterations during ablation.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ex Vivo Characterization of Canine Liver Tissue Viscoelasticity after High-Intensity Focused Ultrasound Ablation

Shahmirzadi

Hou

Chen

et al. 2014

Ultrasound in Medicine & Biology

View full text Add to dashboard Cite

show abstract

“…Investigators have used MRE to quantify the components of the viscoelastic shear modulus of porcine brain tissue (93) and bovine liver tissue (94) and directly compared results with those yielded by oscillatory rheometry. Both studies showed qualitative agreement of trends in the values of G ′ ( ω ) and G ″ ( ω ) with frequency, but rheological tests of porcine brain tissue were performed at a much lower frequency (0.1 to 10 Hz) than that offered by MRE (80–140 Hz), making interpretation of results inconclusive.…”

Section: Measurement Of Human Brain Motion By Phase-contrast Imagimentioning

confidence: 99%

Quantitative Imaging Methods for the Development and Validation of Brain Biomechanics Models

Bayly

Clayton

Genin

2012

Annu. Rev. Biomed. Eng.

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Rapid deformation of brain tissue in response to head impact or acceleration can lead to numerous pathological changes, both immediate and delayed. Modeling and simulation hold promise for illuminating the mechanisms of traumatic brain injury (TBI) and for developing preventive devices and strategies. However, mathematical models have predictive value only if they satisfy two conditions. First, they must capture the biomechanics of the brain as both a material and a structure, including the mechanics of brain tissue and its interactions with the skull. Second, they must be validated by direct comparison with experimental data. Emerging imaging technologies and recent imaging studies provide important data for these purposes. This review describes these techniques and data, with an emphasis on magnetic resonance imaging approaches. In combination, these imaging tools promise to extend our understanding of brain biomechanics and improve our ability to study TBI in silico.

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“…Thus, carefully selecting an appropriate model for the biological organ became more important. Many studies has shown fractional viscoelastic models capture the dynamic viscoelasticity of a biological tissue more precisely than integer order models [10, 12, 29]. From the results in Figure 7, Figure 8, Table 4, and Table 5, it can also be clearly observed that even the two-parameter Springpot model outperforms the five-parameter Generalized Maxwell model.…”

Section: Discussionmentioning

confidence: 84%

Ultra wideband (0.5–16 kHz) MR elastography for robust shear viscoelasticity model identification

2014

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Changes in the viscoelastic parameters of soft biological tissues often correlate with progression of disease, trauma or injury, and response to treatment. Identifying the most appropriate viscoelastic model, then estimating and monitoring the corresponding parameters of that model can improve insight into the underlying tissue structural changes. MR Elastography (MRE) provides a quantitative method of measuring tissue viscoelasticity. In a previous study of the authors [Mag. Res. Med. 70:479-89;2013. doi: 10.1002/mrm.24495], a silicone-based phantom material was examined over the frequency range of 200 Hz to 7.75 kHz using MRE, an unprecedented bandwidth at that time. Six viscoelastic models including four integer order models and two fractional order models, were fit to the wideband viscoelastic data (measured storage and loss moduli as a function of frequency). The "fractional Voigt" model (spring and springpot in parallel) exhibited the best fit and was even able to fit the entire frequency band well when it was identified based only on a small portion of the band. This paper is an extension of that study with a wider frequency range from 500 Hz to 16 kHz. Furthermore, more fractional order viscoelastic models are added to the comparison pool. It is found that added complexity of the viscoelastic model provides only marginal improvement over the "fractional Voigt" model. And, again, the fractional order models show significant improvement over integer order viscoelastic models that have as many or more fitting parameters.

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Viscoelastic properties of liver measured by oscillatory rheometry and multifrequency magnetic resonance elastography

Cited by 91 publications

References 14 publications

Ex Vivo Characterization of Canine Liver Tissue Viscoelasticity after High-Intensity Focused Ultrasound Ablation

Ex Vivo Characterization of Canine Liver Tissue Viscoelasticity after High-Intensity Focused Ultrasound Ablation

Quantitative Imaging Methods for the Development and Validation of Brain Biomechanics Models

Ultra wideband (0.5–16 kHz) MR elastography for robust shear viscoelasticity model identification

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