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Braun J, Bernarding J, Snellings J, Meyer T, Dantas de Moraes PA, Safraou Y, Wells RG, Guo J, Tzschätzsch H, Zappe A, Pagel K, Sauer IM, Hillebrandt KH, Sack I. On the relationship between viscoelasticity and water diffusion in soft biological tissues. Acta Biomater 2024; 182:42-53. [PMID: 38729549 DOI: 10.1016/j.actbio.2024.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 04/10/2024] [Accepted: 05/03/2024] [Indexed: 05/12/2024]
Abstract
Magnetic resonance elastography (MRE) and diffusion-weighted imaging (DWI) are complementary imaging techniques that detect disease based on viscoelasticity and water mobility, respectively. However, the relationship between viscoelasticity and water diffusion is still poorly understood, hindering the clinical translation of combined DWI-MRE markers. We used DWI-MRE to study 129 biomaterial samples including native and cross-linked collagen, glycosaminoglycans (GAGs) with different sulfation levels, and decellularized specimens of pancreas and liver, all with different proportions of solid tissue, or solid fractions. We developed a theoretical framework of the relationship between mechanical loss and tissue-water mobility based on two parameters, solid and fluid viscosity. These parameters revealed distinct DWI-MRE property clusters characterizing weak, moderate, and strong water-network interactions. Sparse networks interacting weakly with water, such as collagen or diluted decellularized tissue, resulted in marginal changes in water diffusion over increasing solid viscosity. In contrast, dense networks with larger solid fractions exhibited both free and hindered water diffusion depending on the polarity of the solid components. For example, polar and highly sulfated GAGs as well as native soft tissues hindered water diffusion despite relatively low solid viscosity. Our results suggest that two fundamental properties of tissue networks, solid fraction and network polarity, critically influence solid and fluid viscosity in biological tissues. Since clinical DWI and MRE are sensitive to these viscosity parameters, the framework we present here can be used to detect tissue remodeling and architectural changes in the setting of diagnostic imaging. STATEMENT OF SIGNIFICANCE: The viscoelastic properties of biological tissues provide a wealth of information on the vital state of cells and host matrix. Combined measurement of viscoelasticity and water diffusion by medical imaging is sensitive to tissue microarchitecture. However, the relationship between viscoelasticity and water diffusion is still poorly understood, hindering full exploitation of these properties as a combined clinical biomarker. Therefore, we analyzed the parameter space accessible by diffusion-weighted imaging (DWI) and magnetic resonance elastography (MRE) and developed a theoretical framework for the relationship between water mobility and mechanical parameters in biomaterials. Our theory of solid material properties related to particle motion can be translated to clinical radiology using clinically established MRE and DWI.
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Affiliation(s)
- Jürgen Braun
- Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Germany
| | | | - Joachim Snellings
- Department of Radiology, Charité - Universitätsmedizin Berlin, Germany
| | - Tom Meyer
- Department of Radiology, Charité - Universitätsmedizin Berlin, Germany
| | | | - Yasmine Safraou
- Department of Radiology, Charité - Universitätsmedizin Berlin, Germany
| | - Rebecca G Wells
- Perelman School of Medicine, University of Pennsylvania, PA, USA
| | - Jing Guo
- Department of Radiology, Charité - Universitätsmedizin Berlin, Germany
| | - Heiko Tzschätzsch
- Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Germany
| | - Andreas Zappe
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Germany
| | - Kevin Pagel
- Department of Chemistry and Biochemistry, Freie Universität Berlin, Germany
| | - Igor M Sauer
- Department of Surgery, CCM | CVK, Experimental Surgery, Charité - Universitätsmedizin Berlin and Berlin Institute of Health, Berlin, Germany
| | - Karl H Hillebrandt
- Department of Surgery, CCM | CVK, Experimental Surgery, Charité - Universitätsmedizin Berlin and Berlin Institute of Health, Berlin, Germany; Berlin Institute of Health at Charité - Universitätsmedizin Berlin, BIH Biomedical Innovation Academy, BIH Charité Clinician Scientist Program, Charitéplatz 1, 10117 Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Germany.
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Kader A, Snellings J, Adams LC, Gottheil P, Mangarova DB, Heyl JL, Kaufmann JO, Moeckel J, Brangsch J, Auer TA, Collettini F, Sauer F, Hamm B, Käs J, Sack I, Makowski MR, Braun J. Sensitivity of magnetic resonance elastography to extracellular matrix and cell motility in human prostate cancer cell line-derived xenograft models. BIOMATERIALS ADVANCES 2024; 161:213884. [PMID: 38723432 DOI: 10.1016/j.bioadv.2024.213884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 04/05/2024] [Accepted: 04/26/2024] [Indexed: 06/04/2024]
Abstract
Prostate cancer (PCa) is a significant health problem in the male population of the Western world. Magnetic resonance elastography (MRE), an emerging medical imaging technique sensitive to mechanical properties of biological tissues, detects PCa based on abnormally high stiffness and viscosity values. Yet, the origin of these changes in tissue properties and how they correlate with histopathological markers and tumor aggressiveness are largely unknown, hindering the use of tumor biomechanical properties for establishing a noninvasive PCa staging system. To infer the contributions of extracellular matrix (ECM) components and cell motility, we investigated fresh tissue specimens from two PCa xenograft mouse models, PC3 and LNCaP, using magnetic resonance elastography (MRE), diffusion-weighted imaging (DWI), quantitative histology, and nuclear shape analysis. Increased tumor stiffness and impaired water diffusion were observed to be associated with collagen and elastin accumulation and decreased cell motility. Overall, LNCaP, while more representative of clinical PCa than PC3, accumulated fewer ECM components, induced less restriction of water diffusion, and exhibited increased cell motility, resulting in overall softer and less viscous properties. Taken together, our results suggest that prostate tumor stiffness increases with ECM accumulation and cell adhesion - characteristics that influence critical biological processes of cancer development. MRE paired with DWI provides a powerful set of imaging markers that can potentially predict prostate tumor development from benign masses to aggressive malignancies in patients. STATEMENT OF SIGNIFICANCE: Xenograft models of human prostate tumor cell lines, allowing correlation of microstructure-sensitive biophysical imaging parameters with quantitative histological methods, can be investigated to identify hallmarks of cancer.
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Affiliation(s)
- Avan Kader
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany; Department of Biology, Chemistry and Pharmacy, Institute of Biology, Freie Universität Berlin, Königin-Luise-Str. 1-3, 14195 Berlin, Germany; Technical University of Munich, Department of Diagnostic and Interventional Radiology, Ismaninger Str. 22, 81675 Munich, Germany.
| | - Joachim Snellings
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany.
| | - Lisa C Adams
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany; Technical University of Munich, Department of Diagnostic and Interventional Radiology, Ismaninger Str. 22, 81675 Munich, Germany.
| | - Pablo Gottheil
- Peter Debye Institute for Soft Matter Physics, Leipzig University, Linnéstraße 5, 04103 Leipzig, Germany
| | - Dilyana B Mangarova
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany.
| | - Jennifer L Heyl
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany.
| | - Jan O Kaufmann
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany; Bundesanstalt für Materialforschung und -prüfung (BAM), Division 1.5 Protein Analysis, Richard-Willstätter-Str. 11, 12489 Berlin, Germany.
| | - Jana Moeckel
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany.
| | - Julia Brangsch
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany; Technical University of Munich, Department of Diagnostic and Interventional Radiology, Ismaninger Str. 22, 81675 Munich, Germany.
| | - Timo A Auer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany; Berlin Insitute of Health (BIH), Berlin, Germany.
| | - Federico Collettini
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany; Berlin Insitute of Health (BIH), Berlin, Germany.
| | - Frank Sauer
- Peter Debye Institute for Soft Matter Physics, Leipzig University, Linnéstraße 5, 04103 Leipzig, Germany.
| | - Bernd Hamm
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany.
| | - Josef Käs
- Peter Debye Institute for Soft Matter Physics, Leipzig University, Linnéstraße 5, 04103 Leipzig, Germany.
| | - Ingolf Sack
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany.
| | - Marcus R Makowski
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany; Technical University of Munich, Department of Diagnostic and Interventional Radiology, Ismaninger Str. 22, 81675 Munich, Germany; King's College London, School of Biomedical Engineering and Imaging Sciences, St Thomas' Hospital, Westminster Bridge Road, London SE1 7EH, United Kingdom.
| | - Jürgen Braun
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Charitéplatz 1, 10117 Berlin, Germany.
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Xie X, Sauer F, Grosser S, Lippoldt J, Warmt E, Das A, Bi D, Fuhs T, Käs JA. Effect of non-linear strain stiffening in eDAH and unjamming. SOFT MATTER 2024; 20:1996-2007. [PMID: 38323652 PMCID: PMC10900305 DOI: 10.1039/d3sm00630a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 01/02/2024] [Indexed: 02/08/2024]
Abstract
In cell clusters, the prominent factors at play encompass contractility-based enhanced tissue surface tension and cell unjamming transition. The former effect pertains to the boundary effect, while the latter constitutes a bulk effect. Both effects share outcomes of inducing significant elongation in cells. This elongation is so substantial that it surpasses the limits of linear elasticity, thereby giving rise to additional effects. To investigate these effects, we employ atomic force microscopy (AFM) to analyze how the mechanical properties of individual cells change under such considerable elongation. Our selection of cell lines includes MCF-10A, chosen for its pronounced demonstration of the extended differential adhesion hypothesis (eDAH), and MDA-MB-436, selected due to its manifestation of cell unjamming behavior. In the AFM analyses, we observe a common trend in both cases: as elongation increases, both cell lines exhibit strain stiffening. Notably, this effect is more prominent in MCF-10A compared to MDA-MB-436. Subsequently, we employ AFM on a dynamic range of 1-200 Hz to probe the mechanical characteristics of cell spheroids, focusing on both surface and bulk mechanics. Our findings align with the results from single cell investigations. Specifically, MCF-10A cells, characterized by strong contractile tissue tension, exhibit the greatest stiffness on their surface. Conversely, MDA-MB-436 cells, which experience significant elongation, showcase their highest stiffness within the bulk region. Consequently, the concept of single cell strain stiffening emerges as a crucial element in understanding the mechanics of multicellular spheroids (MCSs), even in the case of MDA-MB-436 cells, which are comparatively softer in nature.
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Affiliation(s)
- Xiaofan Xie
- Soft Matter Physics Division, Peter Debye Institute for Soft Matter Physics, University of Leipzig, Germany.
| | - Frank Sauer
- Soft Matter Physics Division, Peter Debye Institute for Soft Matter Physics, University of Leipzig, Germany.
| | - Steffen Grosser
- Soft Matter Physics Division, Peter Debye Institute for Soft Matter Physics, University of Leipzig, Germany.
| | - Jürgen Lippoldt
- Soft Matter Physics Division, Peter Debye Institute for Soft Matter Physics, University of Leipzig, Germany.
| | - Enrico Warmt
- Soft Matter Physics Division, Peter Debye Institute for Soft Matter Physics, University of Leipzig, Germany.
| | - Amit Das
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Dapeng Bi
- Department of Physics, Northeastern University, Boston, MA 02115, USA
| | - Thomas Fuhs
- Soft Matter Physics Division, Peter Debye Institute for Soft Matter Physics, University of Leipzig, Germany.
| | - Josef A Käs
- Soft Matter Physics Division, Peter Debye Institute for Soft Matter Physics, University of Leipzig, Germany.
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Sauer F, Grosser S, Shahryari M, Hayn A, Guo J, Braun J, Briest S, Wolf B, Aktas B, Horn L, Sack I, Käs JA. Changes in Tissue Fluidity Predict Tumor Aggressiveness In Vivo. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2303523. [PMID: 37553780 PMCID: PMC10502644 DOI: 10.1002/advs.202303523] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Indexed: 08/10/2023]
Abstract
Cancer progression is caused by genetic changes and associated with various alterations in cell properties, which also affect a tumor's mechanical state. While an increased stiffness has been well known for long for solid tumors, it has limited prognostic power. It is hypothesized that cancer progression is accompanied by tissue fluidization, where portions of the tissue can change position across different length scales. Supported by tabletop magnetic resonance elastography (MRE) on stroma mimicking collagen gels and microscopic analysis of live cells inside patient derived tumor explants, an overview is provided of how cancer associated mechanisms, including cellular unjamming, proliferation, microenvironment composition, and remodeling can alter a tissue's fluidity and stiffness. In vivo, state-of-the-art multifrequency MRE can distinguish tumors from their surrounding host tissue by their rheological fingerprints. Most importantly, a meta-analysis on the currently available clinical studies is conducted and universal trends are identified. The results and conclusions are condensed into a gedankenexperiment about how a tumor can grow and eventually metastasize into its environment from a physics perspective to deduce corresponding mechanical properties. Based on stiffness, fluidity, spatial heterogeneity, and texture of the tumor front a roadmap for a prognosis of a tumor's aggressiveness and metastatic potential is presented.
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Affiliation(s)
- Frank Sauer
- Soft Matter Physics DivisionPeter‐Debye‐Institute for Soft Matter Physics04103LeipzigGermany
| | - Steffen Grosser
- Soft Matter Physics DivisionPeter‐Debye‐Institute for Soft Matter Physics04103LeipzigGermany
- Institute for Bioengineering of CataloniaThe Barcelona Institute for Science and Technology (BIST)Barcelona08028Spain
| | - Mehrgan Shahryari
- Department of RadiologyCharité‐Universitätsmedizin10117BerlinGermany
| | - Alexander Hayn
- Department of HepatologyLeipzig University Hospital04103LeipzigGermany
| | - Jing Guo
- Department of RadiologyCharité‐Universitätsmedizin10117BerlinGermany
| | - Jürgen Braun
- Institute of Medical InformaticsCharité‐Universitätsmedizin10117BerlinGermany
| | - Susanne Briest
- Department of GynecologyLeipzig University Hospital04103LeipzigGermany
| | - Benjamin Wolf
- Department of GynecologyLeipzig University Hospital04103LeipzigGermany
| | - Bahriye Aktas
- Department of GynecologyLeipzig University Hospital04103LeipzigGermany
| | - Lars‐Christian Horn
- Division of Breast, Urogenital and Perinatal PathologyLeipzig University Hospital04103LeipzigGermany
| | - Ingolf Sack
- Department of RadiologyCharité‐Universitätsmedizin10117BerlinGermany
| | - Josef A. Käs
- Soft Matter Physics DivisionPeter‐Debye‐Institute for Soft Matter Physics04103LeipzigGermany
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Jugé L, Foley P, Hatt A, Yeung J, Bilston LE. Ex vivo bovine liver nonlinear viscoelastic properties: MR elastography and rheological measurements. J Mech Behav Biomed Mater 2023; 138:105638. [PMID: 36623403 DOI: 10.1016/j.jmbbm.2022.105638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/28/2022] [Accepted: 12/19/2022] [Indexed: 12/29/2022]
Abstract
INTRODUCTION Knowledge of the nonlinear viscoelastic properties of the liver is important, but the complex tissue behavior outside the linear viscoelastic regime has impeded their characterization, particularly in vivo. Combining static compression with magnetic resonance (MR) elastography has the potential to be a useful imaging method for assessing large deformation mechanical properties of soft tissues in vivo. However, this remains to be verified. Therefore this study aims first to determine whether MR elastography can measure the nonlinear mechanical properties of ex vivo bovine liver tissue under varying levels of uniform and focal preloads (up to 30%), and second to compare MR elastography-derived complex shear modulus with standard rheological measurements. METHOD Nine fresh bovine livers were collected from a local abattoir, and experiments were conducted within 12hr of death. Two cubic samples (∼10 × 10 × 10 cm3) were dissected from each liver and imaged using MR elastography (60 Hz) under 4 levels of uniform and focal preload (1, 10, 20, and 30% of sample width) to investigate the relationship between MR elastography-derived complex shear modulus (G∗) and the maximum principal Right Cauchy Green Strain (C11). Three tissue samples from each of the same 9 livers underwent oscillatory rheometry under the same 4 preloads (1, 10, 20, and 30% strain). MR elastography-derived complex shear modulus (G∗) from the uniform preload was validated against rheometry by fitting the frequency dependence of G∗ with a power-law and extrapolating rheometry-derived G∗ to 60 Hz. RESULTS MR elastography-derived G∗ increased with increasing compressive large deformation strain, and followed a power-law curve (G∗ = 1.73 × C11-0.38, R2 = 0.96). Similarly, rheometry-derived G∗ at 1 Hz, increasing from 0.66 ± 1.03 kPa (1% strain) to 1.84 ± 1.65 kPa (30% strain, RM one-way ANOVA, P < 0.001), and the frequency dependence of G∗ followed a power-law with the exponent decreasing from 0.13 to 0.06 with increasing preload. MR elastography-derived G∗ was 1.4-3.1 times higher than the extrapolated rheometry-derived G∗ at 60 Hz, but the strain dependence was consistent between rheometry and MR elastography measurements. CONCLUSIONS This study demonstrates that MR elastography can detect changes in ex vivo bovine liver complex shear modulus due to either uniform or focal preload and therefore can be a useful technique to characterize nonlinear viscoelastic properties of soft tissue, provided that strains applied to the tissue can be quantified. Although MR elastography could reliably characterize the strain dependence of the ex vivo bovine liver, MR elastography overestimated the complex shear modulus of the tissue compared to rheological measurements, particularly at lower preload (<10%). That is likely to be important in clinical hepatic MR elastography diagnosis studies if preload is not carefully considered. A limitation is the absence of overlapping frequency between rheometry and MR elastography for formal validation.
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Affiliation(s)
- Lauriane Jugé
- Neuroscience Research Australia, PO Box 1165, Randwick NSW 2031, Australia; University of New South Wales, Faculty of Medicine & Health, UNSW Sydney, 18 High St, Kensington NSW 2052, Australia
| | - Patrick Foley
- Neuroscience Research Australia, PO Box 1165, Randwick NSW 2031, Australia
| | - Alice Hatt
- Neuroscience Research Australia, PO Box 1165, Randwick NSW 2031, Australia
| | - Jade Yeung
- Neuroscience Research Australia, PO Box 1165, Randwick NSW 2031, Australia
| | - Lynne E Bilston
- Neuroscience Research Australia, PO Box 1165, Randwick NSW 2031, Australia; University of New South Wales, Faculty of Medicine & Health, UNSW Sydney, 18 High St, Kensington NSW 2052, Australia.
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Reiter R, Zampini MA, Guidetti M, Majumdar S, Royston TJ, Klatt D. Tabletop MR elastography for investigating effects of the freeze-thaw cycle on the mechanical properties of biological tissues. J Mech Behav Biomed Mater 2022; 135:105458. [PMID: 36116341 DOI: 10.1016/j.jmbbm.2022.105458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 08/23/2022] [Accepted: 09/08/2022] [Indexed: 11/26/2022]
Abstract
PURPOSE We aimed at characterizing the effects of the freeze-thaw cycle (FTC) on ex vivo specimens of porcine muscle, liver, kidney, and brain using tabletop magnetic resonance elastography (MRE) combined with rheological modeling. While frozen tissue banks potentially facilitate access to large amounts of well-preserved biospecimens, the impact of the FTC on their viscoelastic properties remains elusive. METHODS In this proof-of-concept study, fresh specimens from porcine lumbar muscle (n = 6), liver (n = 6), kidney (n = 6), and brain (n = 6) were examined before and after the FTC using 0.5T tabletop MRE at 500 Hz, 1000 Hz, 1500 Hz, and 2000 Hz. Seven standard rheological models (Maxwell, Springpot, Voigt, Zener, Jeffrey, fractional Voigt, fractional Zener) were employed to calculate frequency independent viscoelastic parameters. RESULTS The Zener rheological model showed the best fit quality for tissues before and after FTC in the investigated frequency range. Global rheological behavior after the FTC was softer for all tissues. Differences in mechanical parameters between tissues were preserved after the FTC and showed similar trends as before the FTC. Moreover, rheological fit quality improved after the FTC - a result that will be beneficial in investigating frozen tissue bank samples. CONCLUSION Multifrequency tabletop MRE allows rheological characterization of tissue samples before and after the FTC. Our results encourage further biomechanical characterization of frozen tissue bank samples, which may provide valuable information on the diagnostic potential of elastographic methods.
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Affiliation(s)
- Rolf Reiter
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois Chicago, 830 South Wood Street, Chicago, IL, 60612, United States; Department of Radiology, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Hindenburgdamm 30, 12203, Berlin, Germany; Berlin Institute of Health at Charité - Universitätsmedizin Berlin, BIH Biomedical Innovation Academy, BIH Charité Digital Clinician Scientist Program, Charitéplatz 1, 10117, Berlin, Germany.
| | - Marco A Zampini
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois Chicago, 830 South Wood Street, Chicago, IL, 60612, United States; MR Solutions Ltd, Ashbourne House, Old Portsmouth Road, Guildford, Surrey, GU3 1LR, United Kingdom.
| | - Martina Guidetti
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois Chicago, 830 South Wood Street, Chicago, IL, 60612, United States; Department of Orthopedic Surgery, Rush University, 1611 West Harrison Street, Chicago, IL, 60612, United States.
| | - Shreyan Majumdar
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois Chicago, 830 South Wood Street, Chicago, IL, 60612, United States.
| | - Thomas J Royston
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois Chicago, 830 South Wood Street, Chicago, IL, 60612, United States.
| | - Dieter Klatt
- Richard and Loan Hill Department of Biomedical Engineering, University of Illinois Chicago, 830 South Wood Street, Chicago, IL, 60612, United States.
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Yushchenko M, Sarracanie M, Salameh N. Fast acquisition of propagating waves in humans with low-field MRI: Toward accessible MR elastography. SCIENCE ADVANCES 2022; 8:eabo5739. [PMID: 36083901 PMCID: PMC9462689 DOI: 10.1126/sciadv.abo5739] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 07/22/2022] [Indexed: 05/29/2023]
Abstract
Most commonly used at clinical magnetic fields (1.5 to 3 T), magnetic resonance elastography (MRE) captures mechanical wave propagation to reconstruct the mechanical properties of soft tissue with MRI. However, in terms of noninvasively assessing disease progression in a broad range of organs (e.g., liver, breast, skeletal muscle, and brain), its accessibility is limited and its robustness is challenged when magnetic susceptibility differences are encountered. Low-field MRE offers an opportunity to overcome these issues, and yet it has never been demonstrated in vivo in humans with magnetic fields <1.5 T mainly because of the long acquisition times required to achieve a sufficient signal-to-noise ratio. Here, we describe a method to accelerate 3D motion-sensitized MR scans at 0.1 T using only 10% k-space sampling combined with a high-performance detector and an efficient encoding acquisition strategy. Its application is demonstrated in vivo in the human forearm for a single motion-encoding direction in less than 1 min.
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Snellings J, Keshi E, Tang P, Daneshgar A, Willma EC, Haderer L, Klein O, Krenzien F, Malinka T, Asbach P, Pratschke J, Sauer IM, Braun J, Sack I, Hillebrandt K. Solid fraction determines stiffness and viscosity in decellularized pancreatic tissues. BIOMATERIALS ADVANCES 2022; 139:212999. [PMID: 35882147 DOI: 10.1016/j.bioadv.2022.212999] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 06/05/2022] [Accepted: 06/20/2022] [Indexed: 05/29/2023]
Abstract
The role of extracellular matrix (ECM) composition and turnover in mechano-signaling and the metamorphic fate of cells seeded into decellularized tissue can be elucidated by recent developments in non-invasive imaging and biotechnological analysis methods. Because these methods allow accurate quantification of the composition and structural integrity of the ECM, they can be critical in establishing standardized decellularization protocols. This study proposes quantification of the solid fraction, the single-component fraction and the viscoelasticity of decellularized pancreatic tissues using compact multifrequency magnetic resonance elastography (MRE) to assess the efficiency and quality of decellularization protocols. MRE of native and decellularized pancreatic tissues showed that viscoelasticity parameters depend according to a power law on the solid fraction of the decellularized matrix. The parameters can thus be used as highly sensitive markers of the mechanical integrity of soft tissues. Compact MRE allows consistent and noninvasive quantification of the viscoelastic properties of decellularized tissue. Such a method is urgently needed for the standardized monitoring of decellularization processes, evaluation of mechanical ECM properties, and quantification of the integrity of solid structural elements remaining in the decellularized tissue matrix.
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Affiliation(s)
- Joachim Snellings
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Eriselda Keshi
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany
| | - Peter Tang
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany
| | - Assal Daneshgar
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany
| | - Esther C Willma
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany
| | - Luna Haderer
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany
| | - Oliver Klein
- Berlin Institute of Health at Charité - Universitätsmedizin Berlin, BIH Center for Regenerative Therapies, Charitéplatz 1, 10117 Berlin, Germany
| | - Felix Krenzien
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany; Berlin Institute of Health, Germany at Charité - Universitätsmedizin Berlin, BIH Acadamy, Clinician Scientist Program, Charitéplatz 1, 10117 Berlin, Germany
| | - Thomas Malinka
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany
| | - Patrick Asbach
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Johann Pratschke
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany; Cluster of Excellence "Matters of Activity. Image Space Material" funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy - E.XC 2025, Germany
| | - Igor M Sauer
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany; Cluster of Excellence "Matters of Activity. Image Space Material" funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy - E.XC 2025, Germany
| | - Jürgen Braun
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute for Medical Informatics, Charitéplatz 1, 10117 Berlin, Germany
| | - Ingolf Sack
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, Charitéplatz 1, 10117 Berlin, Germany; Cluster of Excellence "Matters of Activity. Image Space Material" funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy - E.XC 2025, Germany.
| | - Karl Hillebrandt
- Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Campus Charité Mitte|Campus Virchow-Klinikum, Charitéplatz 1, 10117 Berlin, Germany; Berlin Institute of Health, Germany at Charité - Universitätsmedizin Berlin, BIH Acadamy, Clinician Scientist Program, Charitéplatz 1, 10117 Berlin, Germany; Cluster of Excellence "Matters of Activity. Image Space Material" funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy - E.XC 2025, Germany
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9
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Abuhattum S, Kotzbeck P, Schlüßler R, Harger A, Ariza de Schellenberger A, Kim K, Escolano JC, Müller T, Braun J, Wabitsch M, Tschöp M, Sack I, Brankatschk M, Guck J, Stemmer K, Taubenberger AV. Adipose cells and tissues soften with lipid accumulation while in diabetes adipose tissue stiffens. Sci Rep 2022; 12:10325. [PMID: 35725987 PMCID: PMC9209483 DOI: 10.1038/s41598-022-13324-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 05/23/2022] [Indexed: 12/14/2022] Open
Abstract
Adipose tissue expansion involves both differentiation of new precursors and size increase of mature adipocytes. While the two processes are well balanced in healthy tissues, obesity and diabetes type II are associated with abnormally enlarged adipocytes and excess lipid accumulation. Previous studies suggested a link between cell stiffness, volume and stem cell differentiation, although in the context of preadipocytes, there have been contradictory results regarding stiffness changes with differentiation. Thus, we set out to quantitatively monitor adipocyte shape and size changes with differentiation and lipid accumulation. We quantified by optical diffraction tomography that differentiating preadipocytes increased their volumes drastically. Atomic force microscopy (AFM)-indentation and -microrheology revealed that during the early phase of differentiation, human preadipocytes became more compliant and more fluid-like, concomitant with ROCK-mediated F-actin remodelling. Adipocytes that had accumulated large lipid droplets were more compliant, and further promoting lipid accumulation led to an even more compliant phenotype. In line with that, high fat diet-induced obesity was associated with more compliant adipose tissue compared to lean animals, both for drosophila fat bodies and murine gonadal adipose tissue. In contrast, adipose tissue of diabetic mice became significantly stiffer as shown not only by AFM but also magnetic resonance elastography. Altogether, we dissect relative contributions of the cytoskeleton and lipid droplets to cell and tissue mechanical changes across different functional states, such as differentiation, nutritional state and disease. Our work therefore sets the basis for future explorations on how tissue mechanical changes influence the behaviour of mechanosensitive tissue-resident cells in metabolic disorders.
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Affiliation(s)
- Shada Abuhattum
- Biotechnology Center, Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47-51, 01307, Dresden, Germany
- Max Planck Institute for the Science of Light and Max-Planck-Zentrum Für Physik Und Medizin, Staudtstr. 2, 91058, Erlangen, Germany
| | - Petra Kotzbeck
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, Deutsches Forschungszentrum Für Gesundheit Und Umwelt GmbH, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
- Division of Plastic, Aesthetic and Reconstructive Surgery, Department of Surgery, Medical University of Graz, Auenbruggerplatz 2, 8036, Graz, Austria
| | - Raimund Schlüßler
- Biotechnology Center, Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47-51, 01307, Dresden, Germany
| | - Alexandra Harger
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, Deutsches Forschungszentrum Für Gesundheit Und Umwelt GmbH, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Angela Ariza de Schellenberger
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Kyoohyun Kim
- Biotechnology Center, Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47-51, 01307, Dresden, Germany
- Max Planck Institute for the Science of Light and Max-Planck-Zentrum Für Physik Und Medizin, Staudtstr. 2, 91058, Erlangen, Germany
| | - Joan-Carles Escolano
- Biotechnology Center, Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47-51, 01307, Dresden, Germany
- Max Planck Institute for the Science of Light and Max-Planck-Zentrum Für Physik Und Medizin, Staudtstr. 2, 91058, Erlangen, Germany
| | - Torsten Müller
- JPK Instruments/Bruker, Colditzstr. 34-36, 12099, Berlin, Germany
| | - Jürgen Braun
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Martin Wabitsch
- Pediatric Endocrinology and Diabetes, Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Eythstr. 24, 89075, Ulm, Germany
| | - Matthias Tschöp
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, Deutsches Forschungszentrum Für Gesundheit Und Umwelt GmbH, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Marko Brankatschk
- Biotechnology Center, Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47-51, 01307, Dresden, Germany
| | - Jochen Guck
- Biotechnology Center, Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47-51, 01307, Dresden, Germany
- Max Planck Institute for the Science of Light and Max-Planck-Zentrum Für Physik Und Medizin, Staudtstr. 2, 91058, Erlangen, Germany
| | - Kerstin Stemmer
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, Deutsches Forschungszentrum Für Gesundheit Und Umwelt GmbH, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany
- Molecular Cell Biology, Institute of Theoretical Medicine, Medical Faculty, University of Augsburg, Universitätsstrasse 2, 86159, Augsburg, Germany
| | - Anna V Taubenberger
- Biotechnology Center, Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47-51, 01307, Dresden, Germany.
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10
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Liquid-Liver Phantom: Mimicking the Viscoelastic Dispersion of Human Liver for Ultrasound- and MRI-Based Elastography. Invest Radiol 2022; 57:502-509. [PMID: 35195086 DOI: 10.1097/rli.0000000000000862] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Tissue stiffness can guide medical diagnoses and is exploited as an imaging contrast in elastography. However, different elastography devices show different liver stiffness values in the same subject, hindering comparison of values and establishment of system-independent thresholds for disease detection. There is a need for standardized phantoms that specifically address the viscosity-related dispersion of stiffness over frequency. To improve standardization of clinical elastography across devices and platforms including ultrasound and magnetic resonance imaging (MRI), a comprehensively characterized phantom is introduced that mimics the dispersion of stiffness of the human liver and can be generated reproducibly. MATERIALS AND METHODS The phantom was made of linear polymerized polyacrylamide (PAAm) calibrated to the viscoelastic properties of healthy human liver in vivo as reported in the literature. Stiffness dispersion was analyzed using the 2-parameter springpot model fitted to the dispersion of shear wave speed of PAAm, which was measured by shear rheometry, ultrasound-based time-harmonic elastography, clinical magnetic resonance elastography (MRE), and tabletop MRE in the frequency range of 5 to 3000 Hz. Imaging parameters for ultrasound and MRI, reproducibility, aging behavior, and temperature dependency were assessed. In addition, the frequency bandwidth of shear wave speed of clinical elastography methods (Aplio i900, Canon; Acuson Sequoia, Siemens; FibroScan, EchoSense) was characterized. RESULTS Within the entire frequency range analyzed in this study, the PAAm phantom reproduced well the stiffness dispersion of human liver in vivo despite its fluid properties under static loading (springpot stiffness parameter, 2.14 [95% confidence interval, 2.08-2.19] kPa; springpot powerlaw exponent, 0.367 [95% confidence interval, 0.362-0.373]). Imaging parameters were close to those of liver in vivo with only slight variability in stiffness values of 0.5% (0.4%, 0.6%), 4.1% (3.9%, 4.5%), and -0.63% (-0.67%, -0.58%), respectively, between batches, over a 6-month period, and per °C increase in temperature. CONCLUSIONS The liquid-liver phantom has useful properties for standardization and development of liver elastography. First, it can be used across clinical and experimental elastography devices in ultrasound and MRI. Second, being a liquid, it can easily be adapted in size and shape to specific technical requirements, and by adding inclusions and scatterers. Finally, because the phantom is based on noncrosslinked linear PAAm constituents, it is easy to produce, indicating potential widespread use among researchers and vendors to standardize liver stiffness measurements.
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11
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Jordan JEL, Bertalan G, Meyer T, Tzschätzsch H, Gauert A, Bramè L, Herthum H, Safraou Y, Schröder L, Braun J, Hagemann AIH, Sack I. Microscopic multifrequency MR elastography for mapping viscoelasticity in zebrafish. Magn Reson Med 2021; 87:1435-1445. [PMID: 34752638 DOI: 10.1002/mrm.29066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 10/12/2021] [Accepted: 10/14/2021] [Indexed: 12/17/2022]
Abstract
PURPOSE The zebrafish (Danio rerio) has become an important animal model in a wide range of biomedical research disciplines. Growing awareness of the role of biomechanical properties in tumor progression and neuronal development has led to an increasing interest in the noninvasive mapping of the viscoelastic properties of zebrafish by elastography methods applicable to bulky and nontranslucent tissues. METHODS Microscopic multifrequency MR elastography is introduced for mapping shear wave speed (SWS) and loss angle (φ) as markers of stiffness and viscosity of muscle, brain, and neuroblastoma tumors in postmortem zebrafish with 60 µm in-plane resolution. Experiments were performed in a 7 Tesla MR scanner at 1, 1.2, and 1.4 kHz driving frequencies. RESULTS Detailed zebrafish viscoelasticity maps revealed that the midbrain region (SWS = 3.1 ± 0.7 m/s, φ = 1.2 ± 0.3 radian [rad]) was stiffer and less viscous than telencephalon (SWS = 2.6 ± 0. 5 m/s, φ = 1.4 ± 0.2 rad) and optic tectum (SWS = 2.6 ± 0.5 m/s, φ = 1.3 ± 0.4 rad), whereas the cerebellum (SWS = 2.9 ± 0.6 m/s, φ = 0.9 ± 0.4 rad) was stiffer but less viscous than both (all p < .05). Overall, brain tissue (SWS = 2.9 ± 0.4 m/s, φ = 1.2 ± 0.2 rad) had similar stiffness but lower viscosity values than muscle tissue (SWS = 2.9 ± 0.5 m/s, φ = 1.4 ± 0.2 rad), whereas neuroblastoma (SWS = 2.4 ± 0.3 m/s, φ = 0.7 ± 0.1 rad, all p < .05) was the softest and least viscous tissue. CONCLUSION Microscopic multifrequency MR elastography-generated maps of zebrafish show many details of viscoelasticity and resolve tissue regions, of great interest in neuromechanical and oncological research and for which our study provides first reference values.
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Affiliation(s)
| | - Gergely Bertalan
- Department of Radiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Tom Meyer
- Department of Radiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Heiko Tzschätzsch
- Department of Radiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Anton Gauert
- Department of Hematology/Oncology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Luca Bramè
- Department of Hematology/Oncology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Helge Herthum
- Institute of Medical Informatics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Yasmine Safraou
- Department of Radiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Leif Schröder
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Anja I H Hagemann
- Department of Hematology/Oncology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
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12
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Garczyńska K, Tzschätzsch H, Assili S, Kühl AA, Häckel A, Schellenberger E, Berndt N, Holzhütter HG, Braun J, Sack I, Guo J. Effect of Post-mortem Interval and Perfusion on the Biophysical Properties of ex vivo Liver Tissue Investigated Longitudinally by MRE and DWI. Front Physiol 2021; 12:696304. [PMID: 34413787 PMCID: PMC8369239 DOI: 10.3389/fphys.2021.696304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 07/12/2021] [Indexed: 11/21/2022] Open
Abstract
Structural changes of soft tissues on the cellular level can be characterized by histopathology, but not longitudinally in the same tissue. Alterations of cellular structures and tissue matrix are associated with changes in biophysical properties which can be monitored longitudinally by quantitative diffusion-weighted imaging (DWI) and magnetic resonance elastography (MRE). In this work, DWI and MRE examinations were performed in a 0.5-Tesla compact scanner to investigate longitudinal changes in water diffusivity, stiffness and viscosity of ex-vivo rat livers for up to 20 h post-mortem (pm). The effect of blood on biophysical parameters was examined in 13 non-perfused livers (containing blood, NPLs) and 14 perfused livers (blood washed out, PLs). Changes in cell shape, cell packing and cell wall integrity were characterized histologically. In all acquisitions, NPLs presented with higher shear-wave speed (c), higher shear-wave penetration rate (a) and smaller apparent-diffusion-coefficients (ADCs) than PL. Time-resolved analysis revealed three distinct phases: (i) an initial phase (up to 2 h pm) with markedly increased c and a and reduced ADCs; (ii) an extended phase with relatively stable values; and (iii) a degradation phase characterized by significant increases in a (10 h pm in NPLs and PLs) and ADCs (10 h pm in NPLs, 13 h pm in PLs). Histology revealed changes in cell shape and packing along with decreased cell wall integrity, indicating tissue degradation in NPLs and PLs 10 h pm. Taken together, our results demonstrate that the biophysical properties of fresh liver tissue rapidly change within 2 h pm, which seems to be an effect of both cytotoxic edema and vascular blood content. Several hours later, disruption of cell walls resulted in higher water diffusivity and wave penetration. These results reveal the individual contributions of vascular components and cellular integrity to liver elastography and provide a biophysical, imaging-based fingerprint of liver tissue degradation.
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Affiliation(s)
- Karolina Garczyńska
- Department of Radiology, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Veterinary Pathology, College of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Heiko Tzschätzsch
- Department of Radiology, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Sanam Assili
- Department of Radiology, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Biology, SUNY Albany, Albany, NY, United States
| | - Anja A. Kühl
- iPATH.Berlin - Core Unit of Charité, Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Akvile Häckel
- Department of Radiology, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Eyk Schellenberger
- Department of Radiology, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Nikolaus Berndt
- Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Berlin Institute of Health (BIH), Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Computational Systems Biochemistry Group, Institute of Biochemistry, Berlin Institute of Health (BIH), Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Hermann-Georg Holzhütter
- Computational Systems Biochemistry Group, Institute of Biochemistry, Berlin Institute of Health (BIH), Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Jing Guo
- Department of Radiology, Berlin Institute of Health, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
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13
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Guidetti M, Zampini MA, Jiang Y, Gambacorta C, Smejkal JP, Crutison J, Pan Y, Klatt D, Royston TJ. Axially- and torsionally-polarized radially converging shear wave MRE in an anisotropic phantom made via Embedded Direct Ink Writing. J Mech Behav Biomed Mater 2021; 119:104483. [PMID: 33838445 PMCID: PMC8137604 DOI: 10.1016/j.jmbbm.2021.104483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/09/2021] [Accepted: 03/15/2021] [Indexed: 11/28/2022]
Abstract
Magnetic Resonance Elastography (MRE) is a non-invasive imaging method to quantitatively map the shear viscoelastic properties of soft tissues. In this study, Embedded Direct Ink Writing is used to fabricate a muscle mimicking anisotropic phantom that may serve as a standard for imaging studies of anisotropic materials. The technique allowed us to obtain a long shelf life silicone-based phantom expressing transverse isotropic mechanical properties. Another goal of the present investigation is to introduce a torsionally-polarized, radially-converging shear wave actuation method for MRE. The implemented design for this novel setup was first validated via its application to isotropic and homogeneous gelatin phantoms. Then, a comparison of the resulting complex wave images from axially- and torsionally-polarized MRE on the developed anisotropic phantom and on a skeletal muscle murine sample is presented, highlighting the value of using multiple actuation and motion encoding polarization directions when studying anisotropic materials.
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Affiliation(s)
- Martina Guidetti
- University of Illinois at Chicago, Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA.
| | | | - Yizhou Jiang
- University of Illinois at Chicago, Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Chiara Gambacorta
- University of Illinois at Chicago, Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Joshua P Smejkal
- University of Illinois at Chicago, Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Joseph Crutison
- University of Illinois at Chicago, Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Yayue Pan
- University of Illinois at Chicago, Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Dieter Klatt
- University of Illinois at Chicago, Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Thomas J Royston
- University of Illinois at Chicago, Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, Chicago, IL 60607, USA
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14
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Zampini MA, Guidetti M, Royston TJ, Klatt D. Measuring viscoelastic parameters in Magnetic Resonance Elastography: a comparison at high and low magnetic field intensity. J Mech Behav Biomed Mater 2021; 120:104587. [PMID: 34034077 DOI: 10.1016/j.jmbbm.2021.104587] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 04/21/2021] [Accepted: 05/08/2021] [Indexed: 12/21/2022]
Abstract
Magnetic Resonance Elastography (MRE) is a non-invasive imaging technique which involves motion-encoding MRI for the estimation of the shear viscoelastic properties of soft tissues through the study of shear wave propagation. The technique has been found informative for disease diagnosis, as well as for monitoring of the effects of therapies. The development of MRE and its validation have been supported by the use of tissue-mimicking phantoms. In this paper we present our new MRE protocol using a low magnetic field tabletop MRI device at 0.5 T and sinusoidal uniaxial excitation in a geometrical focusing condition. Results obtained for gelatin are compared to those previously obtained using high magnetic field MRE at 11.7 T. A multi-frequency investigation is also provided via a comparison of commonly used rheological models: Maxwell, Springpot, Voigt, Zener, Jeffrey, fractional Voigt and fractional Zener. Complex shear modulus values were comparable when processed from images acquired with the tabletop low field scanner and the high field scanner. This study serves as a validation of the presented tabletop MRE protocol and paves the way for MRE experiments on ex-vivo tissue samples in both normal and pathological conditions.
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Affiliation(s)
- Marco Andrea Zampini
- University of Illinois at Chicago, Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, 60607, USA; MR Solutions Ltd, Ashbourne House, Old Portsmouth Rd, Guildford, United Kingdom; Bio-Imaging Lab, Department of Biomedical Sciences, University of Antwerp, Universiteitsplein 1, Wilrijk, Belgium.
| | - Martina Guidetti
- University of Illinois at Chicago, Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Thomas J Royston
- University of Illinois at Chicago, Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
| | - Dieter Klatt
- University of Illinois at Chicago, Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, 60607, USA
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15
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Garczyńska K, Tzschätzsch H, Kühl AA, Morr AS, Lilaj L, Häckel A, Schellenberger E, Berndt N, Holzhütter HG, Braun J, Sack I, Guo J. Changes in Liver Mechanical Properties and Water Diffusivity During Normal Pregnancy Are Driven by Cellular Hypertrophy. Front Physiol 2020; 11:605205. [PMID: 33329058 PMCID: PMC7719759 DOI: 10.3389/fphys.2020.605205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/29/2020] [Indexed: 12/27/2022] Open
Abstract
During pregnancy, the body’s hyperestrogenic state alters hepatic metabolism and synthesis. While biochemical changes related to liver function during normal pregnancy are well understood, pregnancy-associated alterations in biophysical properties of the liver remain elusive. In this study, we investigated 26 ex vivo fresh liver specimens harvested from pregnant and non-pregnant rats by diffusion-weighted imaging (DWI) and magnetic resonance elastography (MRE) in a 0.5-Tesla compact magnetic resonance imaging (MRI) scanner. Water diffusivity and viscoelastic parameters were compared with histological data and blood markers. We found livers from pregnant rats to have (i) significantly enlarged hepatocytes (26 ± 15%, p < 0.001), (ii) increased liver stiffness (12 ± 15%, p = 0.012), (iii) decreased viscosity (−23 ± 14%, p < 0.001), and (iv) increased water diffusivity (12 ± 11%, p < 0.001). In conclusion, increased stiffness and reduced viscosity of the liver during pregnancy are mainly attributable to hepatocyte enlargement. Hypertrophy of liver cells imposes fewer restrictions on intracellular water mobility, resulting in a higher hepatic water diffusion coefficient. Collectively, MRE and DWI have the potential to inform on structural liver changes associated with pregnancy in a clinical context.
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Affiliation(s)
- Karolina Garczyńska
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Heiko Tzschätzsch
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Anja A Kühl
- iPATH.Berlin Core Unit, Charitá - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Anna Sophie Morr
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Ledia Lilaj
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Akvile Häckel
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Eyk Schellenberger
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Nikolaus Berndt
- Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Computational Systems Biochemistry Group, Institute of Biochemistry, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Hermann-Georg Holzhütter
- Computational Systems Biochemistry Group, Institute of Biochemistry, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Jürgen Braun
- Institute of Medical Informatics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Jing Guo
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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16
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Abstract
Wireless power transmission (WPT) is a critical technology that provides an alternative for wireless power and communication with implantable medical devices (IMDs). This article provides a study concentrating on popular WPT techniques for IMDs including inductive coupling, microwave, ultrasound, and hybrid wireless power transmission (HWPT) systems. Moreover, an overview of the major works is analyzed with a comparison of the symmetric and asymmetric design elements, operating frequency, distance, efficiency, and harvested power. In general, with respect to the operating frequency, it is concluded that the ultrasound-based and inductive-based WPTs have a low operating frequency of less than 50 MHz, whereas the microwave-based WPT works at a higher frequency. Moreover, it can be seen that most of the implanted receiver’s dimension is less than 30 mm for all the WPT-based methods. Furthermore, the HWPT system has a larger receiver size compared to the other methods used. In terms of efficiency, the maximum power transfer efficiency is conducted via inductive-based WPT at 95%, compared to the achievable frequencies of 78%, 50%, and 17% for microwave-based, ultrasound-based, and hybrid WPT, respectively. In general, the inductive coupling tactic is mostly employed for transmission of energy to neuro-stimulators, and the ultrasonic method is used for deep-seated implants.
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17
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Manduca A, Bayly PJ, Ehman RL, Kolipaka A, Royston TJ, Sack I, Sinkus R, Van Beers BE. MR elastography: Principles, guidelines, and terminology. Magn Reson Med 2020; 85:2377-2390. [PMID: 33296103 DOI: 10.1002/mrm.28627] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 10/20/2020] [Accepted: 11/09/2020] [Indexed: 12/13/2022]
Abstract
Magnetic resonance elastography (MRE) is a phase contrast-based MRI technique that can measure displacement due to propagating mechanical waves, from which material properties such as shear modulus can be calculated. Magnetic resonance elastography can be thought of as quantitative, noninvasive palpation. It is increasing in clinical importance, has become widespread in the diagnosis and staging of liver fibrosis, and additional clinical applications are being explored. However, publications have reported MRE results using many different parameters, acquisition techniques, processing methods, and varied nomenclature. The diversity of terminology can lead to confusion (particularly among clinicians) about the meaning of and interpretation of MRE results. This paper was written by the MRE Guidelines Committee, a group formalized at the first meeting of the ISMRM MRE Study Group, to clarify and move toward standardization of MRE nomenclature. The purpose of this paper is to (1) explain MRE terminology and concepts to those not familiar with them, (2) define "good practices" for practitioners of MRE, and (3) identify opportunities to standardize terminology, to avoid confusion.
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Affiliation(s)
- Armando Manduca
- Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Philip J Bayly
- Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Richard L Ehman
- Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Arunark Kolipaka
- Department of Radiology, Ohio State University, Columbus, Ohio, USA
| | - Thomas J Royston
- Department of Bioengineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Ingolf Sack
- Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ralph Sinkus
- Imaging Sciences & Biomedical Engineering, Kings College London, London, United Kingdom
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18
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Everwien H, Ariza de Schellenberger A, Haep N, Tzschätzsch H, Pratschke J, Sauer IM, Braun J, Hillebrandt KH, Sack I. Magnetic resonance elastography quantification of the solid-to-fluid transition of liver tissue due to decellularization. J Mech Behav Biomed Mater 2020; 104:103640. [DOI: 10.1016/j.jmbbm.2020.103640] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 01/13/2020] [Accepted: 01/13/2020] [Indexed: 12/12/2022]
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19
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Mura J, Schrank F, Sack I. An analytical solution to the dispersion‐by‐inversion problem in magnetic resonance elastography. Magn Reson Med 2020; 84:61-71. [DOI: 10.1002/mrm.28247] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/16/2020] [Accepted: 02/17/2020] [Indexed: 12/13/2022]
Affiliation(s)
- Joaquin Mura
- Department of Mechanical Engineering Universidad Técnica Federico Santa María Santiago Chile
| | - Felix Schrank
- Department of Radiology Charité ‐ Universitätsmedizin Berlin Germany
| | - Ingolf Sack
- Department of Radiology Charité ‐ Universitätsmedizin Berlin Germany
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20
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Cooley CZ, Stockmann JP, Witzel T, LaPierre C, Mareyam A, Jia F, Zaitsev M, Wenhui Y, Zheng W, Stang P, Scott G, Adalsteinsson E, White JK, Wald LL. Design and implementation of a low-cost, tabletop MRI scanner for education and research prototyping. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 310:106625. [PMID: 31765969 DOI: 10.1016/j.jmr.2019.106625] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/19/2019] [Accepted: 10/20/2019] [Indexed: 06/10/2023]
Abstract
While access to a laboratory MRI system is ideal for teaching MR physics as well as many aspects of signal processing, providing multiple MRI scanners can be prohibitively expensive for educational settings. To address this need, we developed a small, low-cost, open-interface tabletop MRI scanner for academic use. We constructed and tested 20 of these scanners for parallel use by teams of 2-3 students in a teaching laboratory. With simplification and down-scaling to a 1 cm FOV, fully-functional scanners were achieved within a budget of $10,000 USD each. The design was successful for teaching MR principles and basic signal processing skills and serves as an accessible testbed for more advanced MR research projects. Customizable GUIs, pulse sequences, and reconstruction code accessible to the students facilitated tailoring the scanner to the needs of laboratory exercise. The scanners have been used by >800 students in 6 different courses and all designs, schematics, sequences, GUIs, and reconstruction code is open-source.
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Affiliation(s)
- Clarissa Zimmerman Cooley
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA.
| | - Jason P Stockmann
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Thomas Witzel
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Cris LaPierre
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Azma Mareyam
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Feng Jia
- Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Maxim Zaitsev
- Dept. of Radiology, Medical Physics, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Yang Wenhui
- Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
| | - Wang Zheng
- Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
| | - Pascal Stang
- Procyon Engineering, San Jose, CA, USA; Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Greig Scott
- Department of Electrical Engineering, Stanford University, Stanford, CA, USA
| | - Elfar Adalsteinsson
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA; Harvard-MIT Division of Health Sciences Technology, Cambridge, MA, USA
| | - Jacob K White
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Lawrence L Wald
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA; Harvard-MIT Division of Health Sciences Technology, Cambridge, MA, USA
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21
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Guidetti M, Caratelli D, Royston TJ. Converging super-elliptic torsional shear waves in a bounded transverse isotropic viscoelastic material with nonhomogeneous outer boundary. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019. [PMID: 31795656 PMCID: PMC7043840 DOI: 10.1121/1.5134657#suppl] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A theoretical approach was recently introduced [Guidetti and Royston, J. Acoust. Soc. Am. 144, 2312-2323 (2018)] for the radially converging slow shear wave pattern in transverse isotropic materials subjected to axisymmetric excitation normal to the axis of isotropy at the outer boundary of the material. This approach is enabled via transformation to an elliptic coordinate system with isotropic properties. The approach is extended to converging fast shear waves driven by axisymmetric torsional motion polarized in a plane containing the axis of isotropy. The approach involves transformation to a super-elliptic shape with isotropic properties and use of a numerically efficient boundary value approximation.
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Affiliation(s)
- Martina Guidetti
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, 851 South Morgan Street, MC 063, Chicago, Illinois 60607, USA
| | - Diego Caratelli
- The Antenna Company, High Tech Campus 41, 5656 AE, Eindhoven, The , ,
| | - Thomas J Royston
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, 851 South Morgan Street, MC 063, Chicago, Illinois 60607, USA
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22
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Guidetti M, Caratelli D, Royston TJ. Converging super-elliptic torsional shear waves in a bounded transverse isotropic viscoelastic material with nonhomogeneous outer boundary. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:EL451. [PMID: 31795656 PMCID: PMC7043840 DOI: 10.1121/1.5134657] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A theoretical approach was recently introduced [Guidetti and Royston, J. Acoust. Soc. Am. 144, 2312-2323 (2018)] for the radially converging slow shear wave pattern in transverse isotropic materials subjected to axisymmetric excitation normal to the axis of isotropy at the outer boundary of the material. This approach is enabled via transformation to an elliptic coordinate system with isotropic properties. The approach is extended to converging fast shear waves driven by axisymmetric torsional motion polarized in a plane containing the axis of isotropy. The approach involves transformation to a super-elliptic shape with isotropic properties and use of a numerically efficient boundary value approximation.
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Affiliation(s)
- Martina Guidetti
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, 851 South Morgan Street, MC 063, Chicago, Illinois 60607, USA
| | - Diego Caratelli
- The Antenna Company, High Tech Campus 41, 5656 AE, Eindhoven, The , ,
| | - Thomas J Royston
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, 851 South Morgan Street, MC 063, Chicago, Illinois 60607, USA
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23
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Sensitivity of multifrequency magnetic resonance elastography and diffusion-weighted imaging to cellular and stromal integrity of liver tissue. J Biomech 2019; 88:201-208. [DOI: 10.1016/j.jbiomech.2019.03.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 03/27/2019] [Accepted: 03/27/2019] [Indexed: 12/16/2022]
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24
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Sauer F, Oswald L, Ariza de Schellenberger A, Tzschätzsch H, Schrank F, Fischer T, Braun J, Mierke CT, Valiullin R, Sack I, Käs JA. Collagen networks determine viscoelastic properties of connective tissues yet do not hinder diffusion of the aqueous solvent. SOFT MATTER 2019; 15:3055-3064. [PMID: 30912548 DOI: 10.1039/c8sm02264j] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Collagen accounts for the major extracellular matrix (ECM) component in many tissues and provides mechanical support for cells. Magnetic Resonance (MR) Imaging, MR based diffusion measurements and MR Elastography (MRE) are considered sensitive to the microstructure of tissues including collagen networks of the ECM. However, little is known whether water diffusion interacts with viscoelastic properties of tissues. This study combines highfield MR based diffusion measurements, novel compact tabletop MRE and confocal microscopy in collagen networks of different cross-linking states (untreated collagen gels versus additional treatment with glutaraldehyde). The consistency of bulk rheology and MRE within a wide dynamic range is demonstrated in heparin gels, a viscoelastic standard for MRE. Additional crosslinking of collagen led to an 8-fold increased storage modulus, a 4-fold increased loss modulus and a significantly decreased power law exponent, describing multi-relaxational behavior, corresponding to a pronounced transition from viscous-soft to elastic-rigid properties. Collagen network changes were not detectable by MR based diffusion measurements and microscopy which are sensitive to the micrometer scale. The MRE-measured shear modulus is sensitive to collagen fiber interactions which take place on the intrafiber level such as fiber stiffness. The insensitivity of MR based diffusion measurements to collagen hydrogels of different cross-linking states alludes that congeneric collagen structures in connective tissues do not hinder extracellular diffusive water transport. Furthermore, the glutaraldehyde induced rigorous changes in viscoelastic properties indicate that intrafibrillar dissipation is the dominant mode of viscous dissipation in collagen-dominated connective tissue.
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Affiliation(s)
- Frank Sauer
- Soft Matter Physics Division, Peter Debye Institute for Soft Matter Physics, Linnestr. 5, Leipzig, Germany.
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25
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Bigot M, Chauveau F, Beuf O, Lambert SA. Magnetic Resonance Elastography of Rodent Brain. Front Neurol 2018; 9:1010. [PMID: 30538670 PMCID: PMC6277573 DOI: 10.3389/fneur.2018.01010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 11/08/2018] [Indexed: 12/28/2022] Open
Abstract
Magnetic resonance elastography (MRE) is a non-invasive imaging technique, using the propagation of mechanical waves as a probe to palpate biological tissues. It consists in three main steps: production of shear waves within the tissue; encoding subsequent tissue displacement in magnetic resonance images; and extraction of mechanical parameters based on dedicated reconstruction methods. These three steps require an acoustic-frequency mechanical actuator, magnetic resonance imaging acquisition, and a post-processing tool for which no turnkey technology is available. The aim of the present review is to outline the state of the art of reported set-ups to investigate rodent brain mechanical properties. The impact of experimental conditions in dimensioning the set-up (wavelength and amplitude of the propagated wave, spatial resolution, and signal-to-noise ratio of the acquisition) on the accuracy and precision of the extracted parameters is discussed, as well as the influence of different imaging sequences, scanners, electromagnetic coils, and reconstruction algorithms. Finally, the performance of MRE in demonstrating viscoelastic differences between structures constituting the physiological rodent brain, and the changes in brain parameters under pathological conditions, are summarized. The recently established link between biomechanical properties of the brain as obtained on MRE and structural factors assessed by histology is also studied. This review intends to give an accessible outline on how to conduct an elastography experiment, and on the potential of the technique in providing valuable information for neuroscientists.
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Affiliation(s)
- Mathilde Bigot
- Univ. Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, Lyon, France
| | - Fabien Chauveau
- Univ. Lyon, Lyon Neuroscience Research Center, CNRS UMR 5292, INSERM U1028, Univ. Lyon 1, Lyon, France
| | - Olivier Beuf
- Univ. Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, Lyon, France
| | - Simon A Lambert
- Univ. Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, Lyon, France
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26
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Bertalan G, Guo J, Tzschätzsch H, Klein C, Barnhill E, Sack I, Braun J. Fast tomoelastography of the mouse brain by multifrequency single‐shot MR elastography. Magn Reson Med 2018; 81:2676-2687. [DOI: 10.1002/mrm.27586] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 10/04/2018] [Accepted: 10/07/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Gergely Bertalan
- Department of Radiology Charité–Universitätsmedizin Berlin, Campus Charité MitteBerlin Germany
| | - Jing Guo
- Department of Radiology Charité–Universitätsmedizin Berlin, Campus Charité MitteBerlin Germany
| | - Heiko Tzschätzsch
- Department of Radiology Charité–Universitätsmedizin Berlin, Campus Charité MitteBerlin Germany
| | - Charlotte Klein
- Department of Neurology Charité–Universitätsmedizin Berlin, Campus Charité MitteBerlin Germany
| | - Eric Barnhill
- Department of Radiology Charité–Universitätsmedizin Berlin, Campus Charité MitteBerlin Germany
| | - Ingolf Sack
- Department of Radiology Charité–Universitätsmedizin Berlin, Campus Charité MitteBerlin Germany
| | - Jürgen Braun
- Institute of Medical Informatics Charité–Universitätsmedizin Berlin, Campus Benjamin FranklinBerlin Germany
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27
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Garteiser P, Doblas S, Van Beers BE. Magnetic resonance elastography of liver and spleen: Methods and applications. NMR IN BIOMEDICINE 2018; 31:e3891. [PMID: 29369503 DOI: 10.1002/nbm.3891] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 11/16/2017] [Accepted: 12/04/2017] [Indexed: 05/06/2023]
Abstract
The viscoelastic properties of the liver and spleen can be assessed with magnetic resonance elastography (MRE). Several actuators, MRI acquisition sequences and reconstruction algorithms have been proposed for this purpose. Reproducible results are obtained, especially when the examination is performed in standard conditions with the patient fasting. Accurate staging of liver fibrosis can be obtained by measuring liver stiffness or elasticity with MRE. Moreover, emerging evidence shows that assessing the tissue viscous parameters with MRE is useful for characterizing liver inflammation, non-alcoholic steatohepatitis, hepatic congestion, portal hypertension, and hepatic tumors. Further advances such as multifrequency acquisitions and compression-sensitive MRE may provide novel quantitative markers of hepatic and splenic mechanical properties that may improve the diagnosis of hepatic and splenic diseases.
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Affiliation(s)
- Philippe Garteiser
- Laboratory of Imaging Biomarkers, Center of Research on Inflammation, UMR 1149 INSERM-University Paris Diderot, Paris, France
| | - Sabrina Doblas
- Laboratory of Imaging Biomarkers, Center of Research on Inflammation, UMR 1149 INSERM-University Paris Diderot, Paris, France
| | - Bernard E Van Beers
- Laboratory of Imaging Biomarkers, Center of Research on Inflammation, UMR 1149 INSERM-University Paris Diderot, Paris, France
- Department of Radiology, Beaujon University Hospital Paris Nord, Clichy, France
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28
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Guidetti M, Royston TJ. Analytical solution for converging elliptic shear wave in a bounded transverse isotropic viscoelastic material with nonhomogeneous outer boundary. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 144:2312. [PMID: 30404507 PMCID: PMC6197985 DOI: 10.1121/1.5064372] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 08/25/2018] [Accepted: 09/28/2018] [Indexed: 05/17/2023]
Abstract
Dynamic elastography methods-based on optical, ultrasonic, or magnetic resonance imaging-are being developed for quantitatively mapping the shear viscoelastic properties of biological tissues, which are often altered by disease and injury. These diagnostic imaging methods involve analysis of shear wave motion in order to estimate or reconstruct the tissue's shear viscoelastic properties. Most reconstruction methods to date have assumed isotropic tissue properties. However, application to tissues like skeletal muscle and brain white matter with aligned fibrous structure resulting in local transverse isotropic mechanical properties would benefit from analysis that takes into consideration anisotropy. A theoretical approach is developed for the elliptic shear wave pattern observed in transverse isotropic materials subjected to axisymmetric excitation creating radially converging shear waves normal to the fiber axis. This approach, utilizing Mathieu functions, is enabled via a transformation to an elliptic coordinate system with isotropic properties and a ratio of minor and major axes matching the ratio of shear wavelengths perpendicular and parallel to the plane of isotropy in the transverse isotropic material. The approach is validated via numerical finite element analysis case studies. This strategy of coordinate transformation to equivalent isotropic systems could aid in analysis of other anisotropic tissue structures.
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Affiliation(s)
- Martina Guidetti
- Richard and Loan Hill Department of Bioengineering, 851 South Morgan Street, MC 063, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | - Thomas J Royston
- Richard and Loan Hill Department of Bioengineering, 851 South Morgan Street, MC 063, University of Illinois at Chicago, Chicago, Illinois 60607, USA
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29
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Bader KB. The influence of medium elasticity on the prediction of histotripsy-induced bubble expansion and erythrocyte viability. Phys Med Biol 2018; 63:095010. [PMID: 29553049 PMCID: PMC5959013 DOI: 10.1088/1361-6560/aab79b] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Histotripsy is a form of therapeutic ultrasound that liquefies tissue mechanically via acoustic cavitation. Bubble expansion is paramount in the efficacy of histotripsy therapy, and the cavitation dynamics are strongly influenced by the medium elasticity. In this study, an analytic model to predict histotripsy-induced bubble expansion in a fluid was extended to include the effects of medium elasticity. Good agreement was observed between the predictions of the analytic model and numerical computations utilizing highly nonlinear excitations (shock-scattering histotripsy) and purely tensile pulses (microtripsy). No bubble expansion was computed for either form of histotripsy when the elastic modulus was greater than 20 MPa and the peak negative pressure was less than 50 MPa. Strain in the medium due to the expansion of a single bubble was also tabulated. The viability of red blood cells was calculated as a function of distance from the bubble wall based on empirical data of impulsive stretching of erythrocytes. Red blood cells remained viable at distances further than 44 µm from the bubble wall. As the medium elasticity increased, the distance over which bubble expansion-induced strain influenced red blood cells was found to decrease sigmoidally. These results highlight the relationship between tissue elasticity and the efficacy of histotripsy. In addition, an upper medium elasticity limit was identified, above which histotripsy may not be effective for tissue liquefaction.
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Affiliation(s)
- Kenneth B Bader
- Department of Radiology and the Committee on Medical Physics, University of Chicago, Chicago, IL, United States of America
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