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Bayerl C, Safraou Y, Reiter R, Proß V, Lehmann K, Kühl AA, Shahryari M, Hamm B, Sack I, Makowski MR, Braun J, Asbach P. Investigation of hepatic inflammation via viscoelasticity at low and high mechanical frequencies - A magnetic resonance elastography study. J Mech Behav Biomed Mater 2024; 160:106711. [PMID: 39244991 DOI: 10.1016/j.jmbbm.2024.106711] [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: 12/04/2023] [Revised: 08/20/2024] [Accepted: 09/01/2024] [Indexed: 09/10/2024]
Abstract
PURPOSE To study the potential of viscoelastic parameters such as liver stiffness, loss tangent (marker of viscous properties) and viscoelastic dispersion to detect hepatic inflammation by in-vivo and ex-vivo MR elastography (MRE) at low and high vibration frequencies. METHODS 15 patients scheduled for liver tumor resection surgery were prospectively enrolled in this IRB-approved study and underwent multifrequency in-vivo MRE (30-60Hz) at 1.5-T prior to surgery. Immediately after liver resection, tumor-free tissue specimens were examined with ex-vivo MRE (0.8-2.8 kHz) at 0.5-T and histopathologic analysis including NAFLD activity score (NAS) and inflammation score (I-score) as sum of histological sub-features of inflammation. RESULTS In-vivo, in regions where tissue samples were obtained, the loss tangent correlated with the I-score (R = 0.728; p = 0.002) and c-dispersion (stiffness dispersion over frequency) correlated with lobular inflammation (R = -0.559; p = 0.030). In a subgroup of patients without prior chemotherapy, c-dispersion correlated with I-score also in the whole liver (R = -0.682; p = 0.043). ROC analysis of the loss tangent for predicting the I-score showed a high AUC for I ≥ 1 (0.944; p = 0.021), I ≥ 2 (0.804; p = 0.049) and I ≥ 3 (0.944; p = 0.021). Ex-vivo MRE was not sensitive to inflammation, whereas strong correlations were observed between fibrosis and stiffness (R = 0.589; p = 0.021), penetration rate (R = 0.589; p = 0.021), loss tangent (R = -0.629; p = 0.012), and viscoelastic model parameters (spring-pot powerlaw exponent, R = -0.528; p = 0.043; spring-pot shear modulus, R = 0.589; p = 0.021). CONCLUSION Our results suggest that c-dispersion of the liver is sensitive to inflammation when measured in-vivo in the low dynamic range (30-60Hz), while at higher frequencies (0.8-2.8 kHz) viscoelastic parameters are dominated by fibrosis.
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Affiliation(s)
- Christian Bayerl
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, Hindenburgdamm 30, 12203 Berlin, Germany.
| | - Yasmine Safraou
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Rolf Reiter
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, 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
| | - Vanessa Proß
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Kai Lehmann
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Surgery, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Anja A Kühl
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, iPATH.Berlin Core Unit, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Mehrgan Shahryari
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Bernd Hamm
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Ingolf Sack
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Marcus R Makowski
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, Hindenburgdamm 30, 12203 Berlin, Germany; Technical University of Munich (TUM), Germany; School of Medicine & Klinikum Rechts der Isar, Department of Diagnostic and Interventional Radiology, Germany
| | - Jürgen Braun
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, Hindenburgdamm 30, 12203 Berlin, Germany
| | - Patrick Asbach
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Radiology, Hindenburgdamm 30, 12203 Berlin, Germany
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Annio G, Holm S, Mangin G, Penney J, Bacquët R, Mustapha R, Darwish O, Wittgenstein AS, Schregel K, Vilgrain V, Paradis V, Sølna K, Nordsletten DA, Sinkus R. Making sense of scattering: Seeing microstructure through shear waves. SCIENCE ADVANCES 2024; 10:eadp3363. [PMID: 39083612 PMCID: PMC11290519 DOI: 10.1126/sciadv.adp3363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Accepted: 06/26/2024] [Indexed: 08/02/2024]
Abstract
The physics of shear waves traveling through matter carries fundamental insights into its structure, for instance, quantifying stiffness for disease characterization. However, the origin of shear wave attenuation in tissue is currently not properly understood. Attenuation is caused by two phenomena: absorption due to energy dissipation and scattering on structures such as vessels fundamentally tied to the material's microstructure. Here, we present a scattering theory in conjunction with magnetic resonance imaging, which enables the unraveling of a material's innate constitutive and scattering characteristics. By overcoming a three-order-of-magnitude scale difference between wavelength and average intervessel distance, we provide noninvasively a macroscopic measure of vascular architecture. The validity of the theory is demonstrated through simulations, phantoms, in vivo mice, and human experiments and compared against histology as gold standard. Our approach expands the field of imaging by using the dispersion properties of shear waves as macroscopic observable proxies for deciphering the underlying ultrastructures.
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Affiliation(s)
- Giacomo Annio
- Laboratory of Vascular Translation Science, LVTS, U1148, National Institute for Health and Medical Research (INSERM), Paris, France
- Department of Physics and Computational Radiology, Oslo University Hospital, Oslo, Norway
| | - Sverre Holm
- Department of Physics, University of Oslo, Oslo, Norway
| | - Gabrielle Mangin
- Laboratory of Vascular Translation Science, LVTS, U1148, National Institute for Health and Medical Research (INSERM), Paris, France
| | - Jake Penney
- Laboratory of Vascular Translation Science, LVTS, U1148, National Institute for Health and Medical Research (INSERM), Paris, France
| | | | - Rami Mustapha
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK
| | - Omar Darwish
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK
| | | | - Katharina Schregel
- Department of Neuroradiology, Heidelberg University Hospital, Heidelberg, Germany
| | - Valérie Vilgrain
- Department of Radiology, Beaujon Hospital, Clichy, France
- Inflammation Research Center, CRI, U1149, National Institute for Health and Medical Research (INSERM), Paris, France
| | - Valérie Paradis
- Inflammation Research Center, CRI, U1149, National Institute for Health and Medical Research (INSERM), Paris, France
- Department of Pathology, Beaujon Hospital, Clichy, France
| | - Knut Sølna
- Department of Mathematics, University of California at Irvine, Irvine, CA, USA
| | - David Alexander Nordsletten
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK
- Department of Biomedical Engineering and Cardiac Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Ralph Sinkus
- Laboratory of Vascular Translation Science, LVTS, U1148, National Institute for Health and Medical Research (INSERM), Paris, France
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, UK
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Yin M. Shear-Wave Dispersion for Detecting Hepatic Inflammation in Metabolic Dysfunction-associated Steatotic Liver Disease. Radiology 2024; 312:e241420. [PMID: 39162631 PMCID: PMC11366665 DOI: 10.1148/radiol.241420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Revised: 07/24/2024] [Accepted: 07/29/2024] [Indexed: 08/21/2024]
Affiliation(s)
- Meng Yin
- From the Department of Radiology, Center for Advanced Imaging Research, Opus Building, Mayo Clinic, 200 First St SW, Rochester, MN 55905
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Ro SR, Loch FN, Siegmund B, Kühl AA, Neumann GM, Hamm B, Braun J, Sack I, Reiter R. Effects of oral contrast agent on the viscoelastic properties of the terminal ileum investigated using magnetic resonance elastography. Quant Imaging Med Surg 2024; 14:5973-5982. [PMID: 39144032 PMCID: PMC11320487 DOI: 10.21037/qims-24-101] [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: 01/31/2024] [Accepted: 05/16/2024] [Indexed: 08/16/2024]
Abstract
Background While standard clinical magnetic resonance (MR) enterography can detect inflammatory bowel disease, it is of limited value in deciding between medical versus surgical treatment. Alternatively, intestinal MR elastography has the potential to contribute additional information to therapeutic decision-making; however, the influence of bowel distension by oral contrast agent on viscoelastic tissue properties remains elusive. Therefore, we aimed to investigate the influence of oral contrast agent-induced bowel distension on the viscoelastic properties of the terminal ileum in healthy volunteers. Methods In this prospective pilot study, 20 healthy volunteers (33.2±8.2 years; 10 men, 10 women) underwent multifrequency MR elastography using a single-shot spin-echo echo planar imaging sequence at 1.5 Tesla and drive frequencies of 40, 50, 60 and 70 Hz. Maps of shear wave speed (c in ms-1) and loss angle (φ in rad), representing stiffness and viscous properties, respectively, were generated using tomoelastography data processing. The volunteers were scanned before and after ingestion of 1,000 mL of 2% mannitol solution as oral contrast agent. Results There was no significant difference in terminal ileum biomechanical properties before vs. after ingestion of an oral contrast agent (mean c: 1.47±0.24 vs. 1.40±0.25 ms-1 with P=0.37; mean φ: 0.70±0.12 rad vs. 0.68±0.12 rad with P=0.61). Moreover, there was no statistically significant correlation between MR elastography parameters before and after the ingestion of oral contrast (c: r=0.22, P=0.36; φ: r=0.24, P=0.30). Conclusions The results of this study suggest that bowel distension for intestinal MR elastography has no systematic effect on the biomechanical tissue properties of the terminal ileum determined by MR elastography. Therefore, future study protocols appear feasible with or without oral contrast agents.
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Affiliation(s)
- Sa-Ra Ro
- Department of Radiology, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Institute for Diagnostic and Interventional Radiology, Nuclear Medicine and Molecular Imaging, HELIOS Emil von Behring, Academic Educational Hospital of Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Florian N. Loch
- Department of Surgery, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Britta Siegmund
- Department of Gastroenterology, Infectious Disease, Rheumatology, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Anja A. Kühl
- iPATH.Berlin-Immunopathology for Experimental Models, Core Facility, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | | | - Bernd Hamm
- Department of Radiology, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Jürgen Braun
- Department of Medical Informatics, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Ingolf Sack
- Department of Radiology, Charité – Universitätsmedizin Berlin, Berlin, Germany
| | - Rolf Reiter
- Department of Radiology, Charité – Universitätsmedizin Berlin, Berlin, Germany
- Berlin Institute of Health at Charité – Universitätsmedizin Berlin, BIH Biomedical Innovation Academy, BIH Charité Digital Clinician Scientist Program, Berlin, Germany
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Wolf M, Darwish O, Neji R, Eder M, Sunder-Plassmann G, Heinz G, Robinson SD, Schmid AI, Moser EV, Sinkus R, Meyerspeer M. Magnetic resonance elastography resolving all gross anatomical segments of the kidney during controlled hydration. Front Physiol 2024; 15:1327407. [PMID: 38384795 PMCID: PMC10880033 DOI: 10.3389/fphys.2024.1327407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 01/24/2024] [Indexed: 02/23/2024] Open
Abstract
Introduction: Magnetic resonance elastography (MRE) is a non-invasive method to quantify biomechanical properties of human tissues. It has potential in diagnosis and monitoring of kidney disease, if established in clinical practice. The interplay of flow and volume changes in renal vessels, tubule, urinary collection system and interstitium is complex, but physiological ranges of in vivo viscoelastic properties during fasting and hydration have never been investigated in all gross anatomical segments simultaneously. Method: Ten healthy volunteers underwent two imaging sessions, one following a 12-hour fasting period and the second after a drinking challenge of >10 mL per kg body weight (60-75 min before the second examination). High-resolution renal MRE was performed using a novel driver with rotating eccentric mass placed at the posterior-lateral wall to couple waves (50 Hz) to the kidney. The biomechanical parameters, shear wave speed (cs in m/s), storage modulus (Gd in kPa), loss modulus (Gl in kPa), phase angle ( Υ = 2 π atan G l G d ) and attenuation (α in 1/mm) were derived. Accurate separation of gross anatomical segments was applied in post-processing (whole kidney, cortex, medulla, sinus, vessel). Results: High-quality shear waves coupled into all gross anatomical segments of the kidney (mean shear wave displacement: 163 ± 47 μm, mean contamination of second upper harmonics <23%, curl/divergence: 4.3 ± 0.8). Regardless of the hydration state, median Gd of the cortex and medulla (0.68 ± 0.11 kPa) was significantly higher than that of the sinus and vessels (0.48 ± 0.06 kPa), and consistently, significant differences were found in cs, Υ , and Gl (all p < 0.001). The viscoelastic parameters of cortex and medulla were not significantly different. After hydration sinus exhibited a small but significant reduction in median Gd by -0.02 ± 0.04 kPa (p = 0.01), and, consequently, the cortico-sinusoidal-difference in Gd increased by 0.04 ± 0.07 kPa (p = 0.05). Only upon hydration, the attenuation in vessels became lower (0.084 ± 0.013 1/mm) and differed significantly from the whole kidney (0.095 ± 0.007 1/mm, p = 0.01). Conclusion: High-resolution renal MRE with an innovative driver and well-defined 3D segmentation can resolve all renal segments, especially when including the sinus in the analysis. Even after a prolonged hydration period the approach is sensitive to small hydration-related changes in the sinus and in the cortico-sinusoidal-difference.
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Affiliation(s)
- Marcos Wolf
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Omar Darwish
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom
| | - Radhouene Neji
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Michael Eder
- Department of Medicine III, Division of Nephrology and Dialysis, General Hospital and Medical University of Vienna, Vienna, Austria
| | - Gere Sunder-Plassmann
- Department of Medicine III, Division of Nephrology and Dialysis, General Hospital and Medical University of Vienna, Vienna, Austria
| | - Gertraud Heinz
- Institut für Diagnostische und Interventionelle Radiologie, Universitätsklinikum St. Pölten, Sankt Pölten, Austria
| | - Simon Daniel Robinson
- High Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
- Centre of Advanced Imaging, University of Queensland, Brisbane, QLD, Australia
| | - Albrecht Ingo Schmid
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Ewald V. Moser
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Ralph Sinkus
- Institut National de La Santé et de La Recherche Médicale, U1148, Laboratory for Vascular Translational Science, Paris, France
| | - Martin Meyerspeer
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
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van Schelt AS, Gottwald LM, Wassenaar NPM, Runge JH, Sinkus R, Stoker J, Nederveen AJ, Schrauben EM. Single Breath-Hold MR Elastography for Fast Biomechanical Probing of Pancreatic Stiffness. J Magn Reson Imaging 2024; 59:688-698. [PMID: 37194646 DOI: 10.1002/jmri.28773] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/25/2023] [Accepted: 04/26/2023] [Indexed: 05/18/2023] Open
Abstract
BACKGROUND Pancreatic ductal adenocarcinoma (PDAC) stromal disposition is thought to influence chemotherapy efficacy and increase tissue stiffness, which could be quantified noninvasively via MR elastography (MRE). Current methods cause position-based errors in pancreas location over time, hampering accuracy. It would be beneficial to have a single breath-hold acquisition. PURPOSE To develop and test a single breath-hold three-dimensional MRE technique utilizing prospective undersampling and a compressed sensing reconstruction (CS-MRE). STUDY TYPE Prospective. POPULATION A total of 30 healthy volunteers (HV) (31 ± 9 years; 33% male) and five patients with PDAC (69 ± 5 years; 80% male). FIELD STRENGTH/SEQUENCE 3-T, GRE Ristretto MRE. ASSESSMENT First, optimization of multi breath-hold MRE was done in 10 HV using four combinations of vibration frequency, number of measured wave-phase offsets, and TE and looking at MRE quality measures in the pancreas head. Second, viscoelastic parameters delineated in the pancreas head or tumor of CS-MRE were compared against (I) 2D and (II) 3D four breath-hold acquisitions in HV (N = 20) and PDAC patients. Intrasession repeatability was assessed for CS-MRE in a subgroup of healthy volunteers (N = 15). STATISTICAL TESTS Tests include repeated measures analysis of variance (ANOVA), Bland-Altman analysis, and coefficients of variation (CoVs). A P-value <.05 was considered statistically significant. RESULTS Optimization of the four breath-hold acquisitions resulted in 40 Hz vibration frequency, five wave-phases, and echo time (TE) = 6.9 msec as the preferred method (4BH-MRE). CS-MRE quantitative results did not differ from 4BH-MRE. Shear wave speed (SWS) and phase angle differed significantly between HV and PDAC patients using 4BH-MRE or CS-MRE. The limits of agreement for SWS were [-0.09, 0.10] m/second and the within-subject CoV was 4.8% for CS-MRE. DATA CONCLUSION CS-MRE might allow a single breath-hold MRE acquisition with comparable SWS and phase angle as 4BH-MRE, and it may still enable to differentiate between HV and PDAC. LEVEL OF EVIDENCE 2 Technical Efficacy Stage: 2.
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Affiliation(s)
- Anne-Sophie van Schelt
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Imaging and Biomarkers, Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Lukas M Gottwald
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Nienke P M Wassenaar
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Imaging and Biomarkers, Cancer Center Amsterdam, Amsterdam, The Netherlands
| | - Jurgen H Runge
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Department of Radiology, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Ralph Sinkus
- Imaging Sciences and Biomedical Engineering, Kings College London, London, UK
- Department of Radiology, Université de Paris, Paris, France
| | - Jaap Stoker
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Endocrinology, Amsterdam Gastroenterology, Amsterdam, The Netherlands
| | - Aart J Nederveen
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Eric M Schrauben
- Department of Radiology and Nuclear Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
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Darwish OI, Gharib AM, Jeljeli S, Metwalli NS, Feeley J, Rotman Y, Brown RJ, Ouwerkerk R, Kleiner DE, Stäb D, Speier P, Sinkus R, Neji R. Single Breath-Hold 3-Dimensional Magnetic Resonance Elastography Depicts Liver Fibrosis and Inflammation in Obese Patients. Invest Radiol 2023; 58:413-419. [PMID: 36719974 PMCID: PMC10735168 DOI: 10.1097/rli.0000000000000952] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVES Three-dimensional (3D) magnetic resonance elastography (MRE) measures liver fibrosis and inflammation but requires several breath-holds that hamper clinical acceptance. The aim of this study was to evaluate the technical and clinical feasibility of a single breath-hold 3D MRE sequence as a means of measuring liver fibrosis and inflammation in obese patients. METHODS From November 2020 to December 2021, subjects were prospectively enrolled and divided into 2 groups. Group 1 included healthy volunteers (n = 10) who served as controls to compare the single breath-hold 3D MRE sequence with a multiple-breath-hold 3D MRE sequence. Group 2 included liver patients (n = 10) who served as participants to evaluate the clinical feasibility of the single breath-hold 3D MRE sequence in measuring liver fibrosis and inflammation. Controls and participants were scanned at 60 Hz mechanical excitation with the single breath-hold 3D MRE sequence to retrieve the magnitude of the complex-valued shear modulus (|G*| [kPa]), the shear wave speed (Cs [m/s]), and the loss modulus (G" [kPa]). The controls were also scanned with a multiple-breath-hold 3D MRE sequence for comparison, and the participants had histopathology (Ishak scores) for correlation with Cs and G". RESULTS For the 10 controls, 5 were female, and the mean age and body mass index were 33.1 ± 9.5 years and 23.0 ± 2.1 kg/m 2 , respectively. For the 10 participants, 8 were female, and the mean age and body mass index were 45.1 ± 16.5 years and 33.1 ± 4.0 kg/m 2 (obese range), respectively. All participants were suspected of having nonalcoholic fatty liver disease. Bland-Altman analysis of the comparison in controls shows there are nonsignificant differences in |G*|, Cs, and G" below 6.5%, suggesting good consensus between the 2 sequences. For the participants, Cs and G" correlated significantly with Ishak fibrosis and inflammation grades, respectively ( ρ = 0.95, P < 0.001, and ρ = 0.84, P = 0.002). CONCLUSION The single breath-hold 3D MRE sequence may be effective in measuring liver fibrosis and inflammation in obese patients.
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Affiliation(s)
- Omar Isam Darwish
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- INSERM U1148, LVTS, University Paris Diderot, Paris, France
- MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom
| | - Ahmed M. Gharib
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
| | - Sami Jeljeli
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Nader S. Metwalli
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
| | - Jenna Feeley
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
| | - Yaron Rotman
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
| | - Rebecca J. Brown
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
| | - Ronald Ouwerkerk
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
| | | | - Daniel Stäb
- MR Research Collaborations, Siemens Healthcare Limited, Melbourne, Australia
| | - Peter Speier
- MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany
| | - Ralph Sinkus
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- INSERM U1148, LVTS, University Paris Diderot, Paris, France
| | - Radhouene Neji
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom
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8
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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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9
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Mierke CT. Viscoelasticity, Like Forces, Plays a Role in Mechanotransduction. Front Cell Dev Biol 2022; 10:789841. [PMID: 35223831 PMCID: PMC8864183 DOI: 10.3389/fcell.2022.789841] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 01/11/2022] [Indexed: 12/13/2022] Open
Abstract
Viscoelasticity and its alteration in time and space has turned out to act as a key element in fundamental biological processes in living systems, such as morphogenesis and motility. Based on experimental and theoretical findings it can be proposed that viscoelasticity of cells, spheroids and tissues seems to be a collective characteristic that demands macromolecular, intracellular component and intercellular interactions. A major challenge is to couple the alterations in the macroscopic structural or material characteristics of cells, spheroids and tissues, such as cell and tissue phase transitions, to the microscopic interferences of their elements. Therefore, the biophysical technologies need to be improved, advanced and connected to classical biological assays. In this review, the viscoelastic nature of cytoskeletal, extracellular and cellular networks is presented and discussed. Viscoelasticity is conceptualized as a major contributor to cell migration and invasion and it is discussed whether it can serve as a biomarker for the cells' migratory capacity in several biological contexts. It can be hypothesized that the statistical mechanics of intra- and extracellular networks may be applied in the future as a powerful tool to explore quantitatively the biomechanical foundation of viscoelasticity over a broad range of time and length scales. Finally, the importance of the cellular viscoelasticity is illustrated in identifying and characterizing multiple disorders, such as cancer, tissue injuries, acute or chronic inflammations or fibrotic diseases.
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Affiliation(s)
- Claudia Tanja Mierke
- Faculty of Physics and Earth Science, Peter Debye Institute of Soft Matter Physics, Biological Physics Division, University of Leipzig, Leipzig, Germany
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10
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Aryeetey OJ, Frank M, Lorenz A, Estermann SJ, Reisinger AG, Pahr DH. A parameter reduced adaptive quasi-linear viscoelastic model for soft biological tissue in uniaxial tension. J Mech Behav Biomed Mater 2022; 126:104999. [PMID: 34999491 DOI: 10.1016/j.jmbbm.2021.104999] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/04/2021] [Accepted: 11/24/2021] [Indexed: 11/15/2022]
Abstract
Mechanical characterisation of soft viscous materials is essential for many applications including aerospace industries, material models for surgical simulation, and tissue mimicking materials for anatomical models. Constitutive material models are, therefore, necessary to describe soft biological tissues in physiologically relevant strain ranges. Hereby, the adaptive quasi-linear viscoelastic (AQLV) model enables accurate modelling of the strain-dependent non-linear viscoelastic behaviour of soft tissues with a high flexibility. However, the higher flexibility produces a large number of model parameters. In this study, porcine muscle and liver tissue samples were modelled in the framework of the originally published AQLV (3-layers of Maxwell elements) model using four incremental ramp-hold experiments in uniaxial tension. AQLV model parameters were reduced by decreasing model layers (M) as well as the number of experimental ramp-hold steps (N). Leave One out cross validation tests show that the original AQLV model (3M4N) with 19 parameters, accurately describes porcine muscle tissue with an average R2 of 0.90 and porcine liver tissue, R2 of 0.86. Reducing the number of layers (N) in the model produced acceptable model fits for 1-layer (R2 of 0.83) and 2-layer models (R2 of 0.89) for porcine muscle tissue and 1-layer (R2 of 0.84) and 2-layer model (R2 of 0.85) for porcine liver tissue. Additionally, a 2 step (2N) ramp-hold experiment was performed on additional samples of porcine muscle tissue only to further reduce model parameters. Calibrated spring constant values for 2N ramp-hold tests parameters k1 and k2 had a 16.8% and 38.0% deviation from those calibrated for a 4 step (4N) ramp hold experiment. This enables further reduction of material parameters by means of step reduction, effectively reducing the number of parameters required to calibrate the AQLV model from 19 for a 3M4N model to 8 for a 2M2N model, with the added advantage of reducing the time per experiment by 50%. This study proposes a 'reduced-parameter' AQLV model (2M2N) for the modelling of soft biological tissues at finite strain ranges. Sequentially, the comparison of model parameters of soft tissues is easier and the experimental burden is reduced.
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Affiliation(s)
- Othniel J Aryeetey
- TU Wien, Institute of Lightweight Design and Structural Biomechanics, Gumpendorfer Straße 7, 1060, Vienna, Austria; Karl Landsteiner University of Health Sciences, Department of Anatomy and Biomechanics, Division Biomechanics, Dr. Karl-Dorrek-Straße 30, 3500, Krems, Austria
| | - Martin Frank
- Karl Landsteiner University of Health Sciences, Department of Anatomy and Biomechanics, Division Biomechanics, Dr. Karl-Dorrek-Straße 30, 3500, Krems, Austria
| | - Andrea Lorenz
- Austrian Center for Medical Innovation & Technology (ACMIT), Viktor Kaplan-Straße 2/1, 2700, Wiener Neustadt, Austria
| | - Sarah-Jane Estermann
- TU Wien, Institute of Lightweight Design and Structural Biomechanics, Gumpendorfer Straße 7, 1060, Vienna, Austria; Karl Landsteiner University of Health Sciences, Department of Anatomy and Biomechanics, Division Biomechanics, Dr. Karl-Dorrek-Straße 30, 3500, Krems, Austria; Austrian Center for Medical Innovation & Technology (ACMIT), Viktor Kaplan-Straße 2/1, 2700, Wiener Neustadt, Austria
| | - Andreas G Reisinger
- TU Wien, Institute of Lightweight Design and Structural Biomechanics, Gumpendorfer Straße 7, 1060, Vienna, Austria; Karl Landsteiner University of Health Sciences, Department of Anatomy and Biomechanics, Division Biomechanics, Dr. Karl-Dorrek-Straße 30, 3500, Krems, Austria
| | - Dieter H Pahr
- TU Wien, Institute of Lightweight Design and Structural Biomechanics, Gumpendorfer Straße 7, 1060, Vienna, Austria; Karl Landsteiner University of Health Sciences, Department of Anatomy and Biomechanics, Division Biomechanics, Dr. Karl-Dorrek-Straße 30, 3500, Krems, Austria.
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11
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McGrath DM, Bradley CR, Francis ST. In silicoevaluation and optimisation of magnetic resonance elastography of the liver. Phys Med Biol 2021; 66. [PMID: 34678798 DOI: 10.1088/1361-6560/ac3263] [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: 05/12/2021] [Accepted: 10/22/2021] [Indexed: 11/11/2022]
Abstract
Objective.Magnetic resonance elastography (MRE) is widely adopted as a biomarker of liver fibrosis. However,in vivoMRE accuracy is difficult to assess.Approach.Finite element model (FEM) simulation was employed to evaluate liver MRE accuracy and inform methodological optimisation. MRE data was simulated in a 3D FEM of the human torso including the liver, and compared with spin-echo echo-planar imaging MRE acquisitions. The simulated MRE results were compared with the ground truth magnitude of the complex shear modulus (∣G*∣) for varying: (1) ground truth liver ∣G*∣; (2) simulated imaging resolution; (3) added noise; (4) data smoothing. Motion and strain-based signal-to-noise (SNR) metrics were evaluated on the simulated data as a means to select higher-quality voxels for preparation of acquired MRE summary statistics of ∣G*∣.Main results.The simulated MRE accuracy for a given ground truth ∣G*∣ was found to be a function of imaging resolution, motion-SNR and smoothing. At typical imaging resolutions, it was found that due to under-sampling of the MRE wave-field, combined with motion-related noise, the reconstructed simulated ∣G*∣ could contain errors on the scale of the difference between liver fibrosis stages, e.g. 54% error for ground truth ∣G*∣ = 1 kPa. Optimum imaging resolutions were identified for given ground truth ∣G*∣ and motion-SNR levels.Significance.This study provides important knowledge on the accuracy and optimisation of liver MRE. For example, for motion-SNR ≤ 5, to distinguish between liver ∣G*∣ of 2 and 3 kPa (i.e. early-stage liver fibrosis) it was predicted that the optimum isotropic voxel size is 4-6 mm.
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Affiliation(s)
- Deirdre M McGrath
- Sir Peter Mansfield Imaging Centre, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.,NIHR Nottingham Biomedical Research Centre, Radiological Sciences, Division of Clinical Neuroscience, Queens Medical Centre, Nottingham, NG7 2UH, United Kingdom
| | - Christopher R Bradley
- Sir Peter Mansfield Imaging Centre, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.,NIHR Nottingham Biomedical Research Centre, Radiological Sciences, Division of Clinical Neuroscience, Queens Medical Centre, Nottingham, NG7 2UH, United Kingdom
| | - Susan T Francis
- Sir Peter Mansfield Imaging Centre, University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom.,NIHR Nottingham Biomedical Research Centre, Radiological Sciences, Division of Clinical Neuroscience, Queens Medical Centre, Nottingham, NG7 2UH, United Kingdom
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12
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Qu Y, Middleton MS, Loomba R, Glaser KJ, Chen J, Hooker JC, Wolfson T, Covarrubias Y, Valasek MA, Fowler KJ, Zhang YN, Sy E, Gamst AC, Wang K, Mamidipalli A, Schwimmer JB, Song B, Reeder SB, Yin M, Ehman RL, Sirlin CB. Magnetic resonance elastography biomarkers for detection of histologic alterations in nonalcoholic fatty liver disease in the absence of fibrosis. Eur Radiol 2021; 31:8408-8419. [PMID: 33899143 PMCID: PMC8530863 DOI: 10.1007/s00330-021-07988-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 03/25/2021] [Accepted: 04/02/2021] [Indexed: 02/05/2023]
Abstract
OBJECTIVES To investigate associations between histology and hepatic mechanical properties measured using multiparametric magnetic resonance elastography (MRE) in adults with known or suspected nonalcoholic fatty liver disease (NAFLD) without histologic fibrosis. METHODS This was a retrospective analysis of 88 adults who underwent 3T MR exams including hepatic MRE and MR imaging to estimate proton density fat fraction (MRI-PDFF) within 180 days of liver biopsy. Associations between MRE mechanical properties (mean shear stiffness (|G*|) by 2D and 3D MRE, and storage modulus (G'), loss modulus (G″), wave attenuation (α), and damping ratio (ζ) by 3D MRE) and histologic, demographic and anthropometric data were assessed. RESULTS In univariate analyses, patients with lobular inflammation grade ≥ 2 had higher 2D |G*| and 3D G″ than those with grade ≤ 1 (p = 0.04). |G*| (both 2D and 3D), G', and G″ increased with age (rho = 0.25 to 0.31; p ≤ 0.03). In multivariable regression analyses, the association between inflammation grade ≥ 2 remained significant for 2D |G*| (p = 0.01) but not for 3D G″ (p = 0.06); age, sex, or BMI did not affect the MRE-inflammation relationship (p > 0.20). CONCLUSIONS 2D |G*| and 3D G″ were weakly associated with moderate or severe lobular inflammation in patients with known or suspected NAFLD without fibrosis. With further validation and refinement, these properties might become useful biomarkers of inflammation. Age adjustment may help MRE interpretation, at least in patients with early-stage disease. KEY POINTS • Moderate to severe lobular inflammation was associated with hepatic elevated shear stiffness and elevated loss modulus (p =0.04) in patients with known or suspected NAFLD without liver fibrosis; this suggests that with further technical refinement these MRE-assessed mechanical properties may permit detection of inflammation before the onset of fibrosis in NAFLD. • Increasing age is associated with higher hepatic shear stiffness, and storage and loss moduli (rho = 0.25 to 0.31; p ≤ 0.03); this suggests that age adjustment may help interpret MRE results, at least in patients with early-stage NAFLD.
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Affiliation(s)
- Yali Qu
- Department of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China
- Liver Imaging Group, Department of Radiology, University of California at San Diego, La Jolla, CA, 92093-0888, USA
| | - Michael S Middleton
- Liver Imaging Group, Department of Radiology, University of California at San Diego, La Jolla, CA, 92093-0888, USA
| | - Rohit Loomba
- NAFLD Research Center, Division of Gastroenterology, Department of Medicine, University of California at San Diego, La Jolla, CA, USA
- Department of Family Medicine and Public Health, University of California at San Diego, La Jolla, CA, USA
| | - Kevin J Glaser
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Jun Chen
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Jonathan C Hooker
- Liver Imaging Group, Department of Radiology, University of California at San Diego, La Jolla, CA, 92093-0888, USA
| | - Tanya Wolfson
- Computational and Applied Statistics Laboratory, the San Diego Supercomputer Center, University of California at San Diego, La Jolla, CA, USA
| | - Yesenia Covarrubias
- Liver Imaging Group, Department of Radiology, University of California at San Diego, La Jolla, CA, 92093-0888, USA
| | - Mark A Valasek
- Department of Pathology, University of California San Diego, La Jolla, CA, USA
| | - Kathryn J Fowler
- Liver Imaging Group, Department of Radiology, University of California at San Diego, La Jolla, CA, 92093-0888, USA
| | - Yingzhen N Zhang
- Liver Imaging Group, Department of Radiology, University of California at San Diego, La Jolla, CA, 92093-0888, USA
| | - Ethan Sy
- Liver Imaging Group, Department of Radiology, University of California at San Diego, La Jolla, CA, 92093-0888, USA
| | - Anthony C Gamst
- Computational and Applied Statistics Laboratory, the San Diego Supercomputer Center, University of California at San Diego, La Jolla, CA, USA
| | - Kang Wang
- Liver Imaging Group, Department of Radiology, University of California at San Diego, La Jolla, CA, 92093-0888, USA
| | - Adrija Mamidipalli
- Liver Imaging Group, Department of Radiology, University of California at San Diego, La Jolla, CA, 92093-0888, USA
| | - Jeffrey B Schwimmer
- Division of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, University of California at San Diego, La Jolla, CA, USA
- Department of Gastroenterology, Rady Children's Hospital San Diego, San Diego, CA, USA
| | - Bin Song
- Department of Radiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Scott B Reeder
- Departments of Radiology, Medical Physics, Biomedical Engineering, Medicine, and Emergency Medicine, University of Wisconsin, Madison, WI, USA
| | - Meng Yin
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | | | - Claude B Sirlin
- Liver Imaging Group, Department of Radiology, University of California at San Diego, La Jolla, CA, 92093-0888, USA.
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13
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Garteiser P, Pagé G, d'Assignies G, Leitao HS, Vilgrain V, Sinkus R, Van Beers BE. Necro-inflammatory activity grading in chronic viral hepatitis with three-dimensional multifrequency MR elastography. Sci Rep 2021; 11:19386. [PMID: 34588519 PMCID: PMC8481240 DOI: 10.1038/s41598-021-98726-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 09/14/2021] [Indexed: 12/19/2022] Open
Abstract
The purpose of this study was to assess the diagnostic value of multifrequency MR elastography for grading necro-inflammation in the liver. Fifty participants with chronic hepatitis B or C were recruited for this institutional review board-approved study. Their liver was examined with multifrequency MR elastography. The storage, shear and loss moduli, and the damping ratio were measured at 56 Hz. The multifrequency wave dispersion coefficient of the shear modulus was calculated. The measurements were compared to reference markers of necro-inflammation and fibrosis with Spearman correlations and multiple regression analysis. Diagnostic accuracy was assessed. At multiple regression analysis, necro-inflammation was the only determinant of the multifrequency dispersion coefficient, whereas fibrosis was the only determinant of the storage, loss and shear moduli. The multifrequency dispersion coefficient had the largest AUC for necro-inflammatory activity A ≥ 2 [0.84 (0.71-0.93) vs. storage modulus AUC: 0.65 (0.50-0.79), p = 0.03], whereas the storage modulus had the largest AUC for fibrosis F ≥ 2 [AUC (95% confidence intervals) 0.91 (0.79-0.98)] and cirrhosis F4 [0.97 (0.88-1.00)]. The measurement of the multifrequency dispersion coefficient at three-dimensional MR elastography has the potential to grade liver necro-inflammation in patients with chronic vial hepatitis.
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Affiliation(s)
- Philippe Garteiser
- Laboratory of Imaging Biomarkers, Center for Research on Inflammation, UMR 1149 Inserm, Université de Paris, 75018, Paris, France.
| | - Gwenaël Pagé
- Laboratory of Imaging Biomarkers, Center for Research on Inflammation, UMR 1149 Inserm, Université de Paris, 75018, Paris, France
| | - Gaspard d'Assignies
- Laboratory of Imaging Biomarkers, Center for Research on Inflammation, UMR 1149 Inserm, Université de Paris, 75018, Paris, France
- Department of Radiology, Beaujon University Hospital Paris Nord, AP-HP, 92110, Clichy, France
| | - Helena S Leitao
- Laboratory of Imaging Biomarkers, Center for Research on Inflammation, UMR 1149 Inserm, Université de Paris, 75018, Paris, France
- Department of Radiology, Beaujon University Hospital Paris Nord, AP-HP, 92110, Clichy, France
| | - Valérie Vilgrain
- Laboratory of Imaging Biomarkers, Center for Research on Inflammation, UMR 1149 Inserm, Université de Paris, 75018, Paris, France
- Department of Radiology, Beaujon University Hospital Paris Nord, AP-HP, 92110, Clichy, France
| | - Ralph Sinkus
- Laboratory for Vascular Translational Science, UMR 1148 Inserm, Université de Paris, 75018, Paris, France
| | - Bernard E Van Beers
- Laboratory of Imaging Biomarkers, Center for Research on Inflammation, UMR 1149 Inserm, Université de Paris, 75018, Paris, France
- Department of Radiology, Beaujon University Hospital Paris Nord, AP-HP, 92110, Clichy, France
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14
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Reiter R, Loch FN, Kamphues C, Bayerl C, Marticorena Garcia SR, Siegmund B, Kühl AA, Hamm B, Braun J, Sack I, Asbach P. Feasibility of Intestinal MR Elastography in Inflammatory Bowel Disease. J Magn Reson Imaging 2021; 55:815-822. [PMID: 34254389 DOI: 10.1002/jmri.27833] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND While MR enterography allows detection of inflammatory bowel disease (IBD), the findings continue to be of limited use in guiding treatment-medication vs. surgery. PURPOSE To test the feasibility of MR elastography of the gut in healthy volunteers and IBD patients. STUDY TYPE Prospective pilot. POPULATION Forty subjects (healthy volunteers: n = 20, 37 ± 14 years, 10 women; IBD patients: n = 20 (ulcerative colitis n = 9, Crohn's disease n = 11), 41 ± 15 years, 11 women). FIELD STRENGTH/SEQUENCE Multifrequency MR elastography using a single-shot spin-echo echo planar imaging sequence at 1.5 T with drive frequencies of 40, 50, 60, and 70 Hz. ASSESSMENT Maps of shear-wave speed (SWS, in m/s) and loss angle (φ, in rad), representing stiffness and solid-fluid behavior, respectively, were generated using tomoelastography data processing. Histopathological analysis of surgical specimens was used as reference standard in patients. STATISTICAL TESTS Unpaired t-test, one-way analysis of variance followed by Tukey post hoc analysis, Pearson's correlation coefficient and area under the receiver operating characteristic curve (AUC) with 95%-confidence interval (CI). Significance level of 5%. RESULTS MR elastography was feasible in all 40 subjects (100% technical success rate). SWS and φ were significantly increased in IBD by 21% and 20% (IBD: 1.45 ± 0.14 m/s and 0.78 ± 0.12 rad; healthy volunteers: 1.20 ± 0.14 m/s and 0.65 ± 0.06 rad), whereas no significant differences were found between ulcerative colitis and Crohn's disease (P = 0.74 and 0.90, respectively). In a preliminary assessment, a high diagnostic accuracy in detecting IBD was suggested by an AUC of 0.90 (CI: 0.81-0.96) for SWS and 0.84 (CI: 0.71-0.95) for φ. DATA CONCLUSION In this pilot study, our results demonstrated the feasibility of MR elastography of the gut and showed an excellent diagnostic performance in predicting IBD. EVIDENCE LEVEL 1 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Rolf Reiter
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Hindenburgdamm 30, Berlin, 12203, Germany.,Berlin Institute of Health (BIH), Anna-Louisa-Karsch-Str. 2, Berlin, 10178, Germany
| | - Florian N Loch
- Department of Surgery, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Hindenburgdamm 30, Berlin, 12203, Germany
| | - Carsten Kamphues
- Department of Surgery, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Hindenburgdamm 30, Berlin, 12203, Germany
| | - Christian Bayerl
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Hindenburgdamm 30, Berlin, 12203, Germany
| | - Stephan R Marticorena Garcia
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Hindenburgdamm 30, Berlin, 12203, Germany
| | - Britta Siegmund
- Department of Gastroenterology, Infectious Disease, Rheumatology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Hindenburgdamm 30, Berlin, 12203, Germany
| | - Anja A Kühl
- iPATH.Berlin-Immunopathology for Experimental Models, Core Facility, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Hindenburgdamm 30, Berlin, 12203, Germany
| | - Bernd Hamm
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Hindenburgdamm 30, Berlin, 12203, Germany
| | - Jürgen Braun
- Department of Medical Informatics, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Hindenburgdamm 30, Berlin, 12203, Germany
| | - Ingolf Sack
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Hindenburgdamm 30, Berlin, 12203, Germany
| | - Patrick Asbach
- Department of Radiology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Hindenburgdamm 30, Berlin, 12203, Germany
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15
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Influence of fibrosis progression on the viscous properties of in vivo liver tissue elucidated by shear wave dispersion in multifrequency MR elastography. J Mech Behav Biomed Mater 2021; 121:104645. [PMID: 34166871 DOI: 10.1016/j.jmbbm.2021.104645] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 05/14/2021] [Accepted: 06/09/2021] [Indexed: 12/19/2022]
Abstract
PURPOSE Many elastography studies have shown that liver stiffness increases with fibrosis and thus can be used as a reliable marker for noninvasively staging fibrosis. However, the sensitivity of viscosity-related mechanical parameters, such as shear wave dispersion, to liver fibrosis is less well understood. METHODS In this proof-of-concept study, 15 healthy volunteers and 37 patients with chronic liver disease and biopsy-proven fibrosis were prospectively investigated by MR elastography at six drive frequencies of 35-60 Hz. Maps of shear wave speed (SWS, in m/s) and loss angle (φ, in rad), as a marker of stiffness and viscous properties, respectively, were generated using tomoelastography data processing. The Child-Pugh score was used to assess cirrhosis severity. RESULTS While SWS increased with fibrosis (F0: 1.53 ± 0.11 m/s, F1-F3: 1.71 ± 0.17 m/s, F4: 2.50 ± 0.39 m/s; P < 0.001), φ remained unchanged during mild to severe fibrosis (F0: 0.63 ± 0.05 rad, F1-F3: 0.60 ± 0.05 rad, P = 0.21) but increased in cirrhosis (F4: 0.81 ± 0.16 rad; P < 0.001). Correspondingly, the slope of SWS-dispersion within the investigated range of vibration frequencies increased from insignificant (F0-F3: 0.010 ± 0.007 m/s/Hz) to significant (F4: 0.038 ± 0.025 m/s/Hz; P = 0.005). Significant correlation with the Child-Pugh score was found for φ (R = 0.60, P = 0.01) but not for SWS. CONCLUSION Although cirrhosis is associated with liver stiffening and, intuitively, transition towards more rigid material properties, the observed increases in φ and slope of SWS-dispersion indicate abnormally high mechanical friction in cirrhotic livers. This biophysical signature might provide a prognostic imaging marker for the detection of pathological processes associated with fibrosis independent of stiffness.
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16
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Troelstra MA, Witjes JJ, van Dijk AM, Mak AL, Gurney-Champion O, Runge JH, Zwirs D, Stols-Gonçalves D, Zwinderman AH, Ten Wolde M, Monajemi H, Ramsoekh S, Sinkus R, van Delden OM, Beuers UH, Verheij J, Nieuwdorp M, Nederveen AJ, Holleboom AG. Assessment of Imaging Modalities Against Liver Biopsy in Nonalcoholic Fatty Liver Disease: The Amsterdam NAFLD-NASH Cohort. J Magn Reson Imaging 2021; 54:1937-1949. [PMID: 33991378 PMCID: PMC9290703 DOI: 10.1002/jmri.27703] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 05/04/2021] [Accepted: 05/06/2021] [Indexed: 12/17/2022] Open
Abstract
Background Noninvasive diagnostic methods are urgently required in disease stratification and monitoring in nonalcoholic fatty liver disease (NAFLD). Multiparametric magnetic resonance imaging (MRI) is a promising technique to assess hepatic steatosis, inflammation, and fibrosis, potentially enabling noninvasive identification of individuals with active and advanced stages of NAFLD. Purpose To examine the diagnostic performance of multiparametric MRI for the assessment of disease severity along the NAFLD disease spectrum with comparison to histological scores. Study Type Prospective, cohort. Population Thirty‐seven patients with NAFLD. Field Strength/Sequence Multiparametric MRI at 3.0 T consisted of magnetic resonance (MR) spectroscopy (MRS) with multi‐echo stimulated‐echo acquisition mode, magnitude‐based and three‐point Dixon using a two‐dimensional multi‐echo gradient echo, MR elastography (MRE) using a generalized multishot gradient‐recalled echo sequence and intravoxel incoherent motion (IVIM) using a multislice diffusion weighted single‐shot echo‐planar sequence. Assessment Histological steatosis grades were compared to proton density fat fraction measured by MRS (PDFFMRS), magnitude‐based MRI (PDFFMRI‐M), and three‐point Dixon (PDFFDixon), as well as FibroScan® controlled attenuation parameter (CAP). Fibrosis and disease activity were compared to IVIM and MRE. FibroScan® liver stiffness measurements were compared to fibrosis levels. Diagnostic performance of all imaging parameters was determined for distinction between simple steatosis and nonalcoholic steatohepatitis (NASH). Statistical Tests Spearman's rank test, Kruskal–Wallis test, Dunn's post‐hoc test with Holm‐Bonferroni P‐value adjustment, receiver operating characteristic curve analysis. A P‐value <0.05 was considered statistically significant. Results Histological steatosis grade correlated significantly with PDFFMRS (rs = 0.66, P < 0.001), PDFFMRI‐M (rs = 0.68, P < 0.001), and PDFFDixon (rs = 0.67, P < 0.001), whereas no correlation was found with CAP. MRE and IVIM diffusion and perfusion significantly correlated with disease activity (rs = 0.55, P < 0.001, rs = −0.40, P = 0.016, rs = −0.37, P = 0.027, respectively) and fibrosis (rs = 0.55, P < 0.001, rs = −0.46, P = 0.0051; rs = −0.53, P < 0.001, respectively). MRE and IVIM diffusion had the highest area‐under‐the‐curve for distinction between simple steatosis and NASH (0.79 and 0.73, respectively). Data Conclusion Multiparametric MRI is a promising method for noninvasive, accurate, and sensitive distinction between simple hepatic steatosis and NASH, as well as for the assessment of steatosis and fibrosis severity. Level of Evidence 2 Technical Efficacy 2
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Affiliation(s)
- Marian A Troelstra
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Julia J Witjes
- Department of Internal and Vascular Medicine, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Anne-Marieke van Dijk
- Department of Internal and Vascular Medicine, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Anne L Mak
- Department of Internal and Vascular Medicine, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Oliver Gurney-Champion
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Jurgen H Runge
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Diona Zwirs
- Department of Internal and Vascular Medicine, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Daniela Stols-Gonçalves
- Department of Internal and Vascular Medicine, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Aelko H Zwinderman
- Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Marije Ten Wolde
- Department of Internal Medicine, Flevoziekenhuis, Almere, The Netherlands
| | - Houshang Monajemi
- Department of Internal Medicine, Rijnstate Ziekenhuis, Arnhem, The Netherlands
| | - Sandjai Ramsoekh
- Department of Gastroenterology and Hepatology, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Ralph Sinkus
- Inserm U1148, LVTS, University Paris Diderot, University Paris 13, Paris, France.,School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Otto M van Delden
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Ulrich H Beuers
- Department of Gastroenterology and Hepatology, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Joanne Verheij
- Department of Pathology, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Max Nieuwdorp
- Department of Internal and Vascular Medicine, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Aart J Nederveen
- Department of Radiology and Nuclear Medicine, Amsterdam University Medical Centres, Amsterdam, The Netherlands
| | - Adriaan G Holleboom
- Department of Internal and Vascular Medicine, Amsterdam University Medical Centres, Amsterdam, The Netherlands
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17
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Gomez A, Rus G, Saffari N. Wave Propagation in a Fractional Viscoelastic Tissue Model: Application to Transluminal Procedures. SENSORS (BASEL, SWITZERLAND) 2021; 21:2778. [PMID: 33920801 PMCID: PMC8071186 DOI: 10.3390/s21082778] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/07/2021] [Accepted: 04/13/2021] [Indexed: 12/27/2022]
Abstract
In this article, a wave propagation model is presented as the first step in the development of a new type of transluminal procedure for performing elastography. Elastography is a medical imaging modality for mapping the elastic properties of soft tissue. The wave propagation model is based on a Kelvin Voigt Fractional Derivative (KVFD) viscoelastic wave equation, and is numerically solved using a Finite Difference Time Domain (FDTD) method. Fractional rheological models, such as the KVFD, are particularly well suited to model the viscoelastic response of soft tissue in elastography. The transluminal procedure is based on the transmission and detection of shear waves through the luminal wall. Shear waves travelling through the tissue are perturbed after encountering areas of altered elasticity. These perturbations carry information of medical interest that can be extracted by solving the inverse problem. Scattering from prostate tumours is used as an example application to test the model. In silico results demonstrate that shear waves are satisfactorily transmitted through the luminal wall and that echoes, coming from reflected energy at the edges of an area of altered elasticity, which are feasibly detectable by using the transluminal approach. The model here presented provides a useful tool to establish the feasibility of transluminal procedures based on wave propagation and its interaction with the mechanical properties of the tissue outside the lumen.
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Affiliation(s)
- Antonio Gomez
- UCL Mechanical Engineering, University College London, London WC1E 7JE, UK;
- Instituto de Investigación Biosanitaria, ibs.GRANADA, 18012 Granada, Spain
| | - Guillermo Rus
- Instituto de Investigación Biosanitaria, ibs.GRANADA, 18012 Granada, Spain
- Structural Mechanics Department, University of Granada, 18071 Granada, Spain;
- Excellence Research Unit “ModelingNature” (MNat), University of Granada, 18071 Granada, Spain
| | - Nader Saffari
- UCL Mechanical Engineering, University College London, London WC1E 7JE, UK;
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18
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Gomez A, Hurtado M, Callejas A, Torres J, Saffari N, Rus G. Experimental Evidence of Generation and Reception by a Transluminal Axisymmetric Shear Wave Elastography Prototype. Diagnostics (Basel) 2021; 11:diagnostics11040645. [PMID: 33918357 PMCID: PMC8067333 DOI: 10.3390/diagnostics11040645] [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: 12/11/2020] [Revised: 03/20/2021] [Accepted: 03/30/2021] [Indexed: 01/30/2023] Open
Abstract
Experimental evidence on testing a non-ultrasonic-based probe for a new approach in transluminal elastography was presented. The proposed modality generated shear waves by inducing oscillatory rotation on the lumen wall. Detection of the propagated waves was achieved at a set of receivers in mechanical contact with the lumen wall. The excitation element of the probe was an electromagnetic rotational actuator whilst the sensing element was comprised by a uniform anglewise arrangement of four piezoelectric receivers. The prototype was tested in two soft-tissue-mimicking phantoms that contained lumenlike conduits and stiffer inclusions. The shear wave speed of the different components of the phantoms was characterized using shear wave elastography. These values were used to estimate the time-of-flight of the expected reflections. Ultrafast ultrasound imaging, based on Loupas’ algorithm, was used to estimate the displacement field in transversal planes to the lumenlike conduit and to compare against the readouts from the transluminal transmission–reception tests. Experimental observations between ultrafast imaging and the transluminal probe were in good agreement, and reflections due to the stiffer inclusions were detected by the transluminal probe. The obtained experimental evidence provided proof-of-concept for the transluminal elastography probe and encouraged further exploration of clinical applications.
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Affiliation(s)
- Antonio Gomez
- Department of Mechanical Engineering, University College London, London WC1E 6BT, UK; (A.G.); (N.S.)
| | - Manuel Hurtado
- Department of Structural Mechanics, University of Granada, 18071 Granada, Spain; (M.H.); (J.T.); (G.R.)
| | - Antonio Callejas
- Department of Structural Mechanics, University of Granada, 18071 Granada, Spain; (M.H.); (J.T.); (G.R.)
- Instituto de Investigación Biosanitaria, ibs.GRANADA, 18012 Granada, Spain
- Correspondence:
| | - Jorge Torres
- Department of Structural Mechanics, University of Granada, 18071 Granada, Spain; (M.H.); (J.T.); (G.R.)
- Instituto de Investigación Biosanitaria, ibs.GRANADA, 18012 Granada, Spain
| | - Nader Saffari
- Department of Mechanical Engineering, University College London, London WC1E 6BT, UK; (A.G.); (N.S.)
| | - Guillermo Rus
- Department of Structural Mechanics, University of Granada, 18071 Granada, Spain; (M.H.); (J.T.); (G.R.)
- Instituto de Investigación Biosanitaria, ibs.GRANADA, 18012 Granada, Spain
- Excellence Research Unit “ModelingNature” (MNat), Universidad de Granada, 18071 Granada, Spain
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19
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Runge JH. Editorial for “Dual‐Frequency MR Elastography to Differentiate Between Inflammation and Fibrosis of the Liver: Comparison With Histopathology”. J Magn Reson Imaging 2020; 51:1594-1595. [DOI: 10.1002/jmri.26967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 09/25/2019] [Indexed: 11/06/2022] Open
Affiliation(s)
- Jurgen Henk Runge
- Department of Radiology and Nuclear MedicineAmsterdam UMC, location AMC Amsterdam Netherlands
- King's College London, School of Biomedical Engineering & Imaging Sciences London UK
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20
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Capilnasiu A, Bilston L, Sinkus R, Nordsletten D. Nonlinear viscoelastic constitutive model for bovine liver tissue. Biomech Model Mechanobiol 2020; 19:1641-1662. [PMID: 32040652 PMCID: PMC7502455 DOI: 10.1007/s10237-020-01297-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 01/21/2020] [Indexed: 12/26/2022]
Abstract
Soft tissue mechanical characterisation is important in many areas of medical research. Examples span from surgery training, device design and testing, sudden injury and disease diagnosis. The liver is of particular interest, as it is the most commonly injured organ in frontal and side motor vehicle crashes, and also assessed for inflammation and fibrosis in chronic liver diseases. Hence, an extensive rheological characterisation of liver tissue would contribute to advancements in these areas, which are dependent upon underlying biomechanical models. The aim of this paper is to define a liver constitutive equation that is able to characterise the nonlinear viscoelastic behaviour of liver tissue under a range of deformations and frequencies. The tissue response to large amplitude oscillatory shear (1–50%) under varying preloads (1–20%) and frequencies (0.5–2 Hz) is modelled using viscoelastic-adapted forms of the Mooney–Rivlin, Ogden and exponential models. These models are fit to the data using classical or modified objective norms. The results show that all three models are suitable for capturing the initial nonlinear regime, with the latter two being capable of capturing, simultaneously, the whole deformation range tested. The work presented here provides a comprehensive analysis across several material models and norms, leading to an identifiable constitutive equation that describes the nonlinear viscoelastic behaviour of the liver.
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Affiliation(s)
- Adela Capilnasiu
- Division of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.
| | - Lynne Bilston
- Prince of Wales Clinical School, University of New South Wales, Sydney, Australia.,Neuroscience Research Australia, Sydney, Australia
| | - Ralph Sinkus
- Division of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.,Inserm U1148, LVTS, University Paris Diderot, University Paris 13, 75018, Paris, France
| | - David Nordsletten
- Division of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.,Department of Biomedical Engineering and Cardiac Surgery, University of Michigan, Ann Arbor, USA
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21
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Bigot M, Chauveau F, Amaz C, Sinkus R, Beuf O, Lambert SA. The apparent mechanical effect of isolated amyloid-β and α-synuclein aggregates revealed by multi-frequency MRE. NMR IN BIOMEDICINE 2020; 33:e4174. [PMID: 31696585 DOI: 10.1002/nbm.4174] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 08/11/2019] [Accepted: 08/13/2019] [Indexed: 06/10/2023]
Abstract
Several biological processes are involved in dementia, and fibrillar aggregation of misshaped endogenous proteins appears to be an early hallmark of neurodegenerative disease. A recently developed means of studying neurodegenerative diseases is magnetic resonance elastography (MRE), an imaging technique investigating the mechanical properties of tissues. Although mechanical changes associated with these diseases have been detected, the specific signal of fibrils has not yet been isolated in clinical or preclinical studies. The current study aims to exploit the fractal-like properties of fibrils to separate them from nonaggregated proteins using a multi-frequency MRE power law exponent in a phantom study. Two types of fibril, α-synuclein (α-Syn) and amyloid-β (Aβ), and a nonaggregated protein, bovine serum albumin, used as control, were incorporated in a dedicated nondispersive agarose phantom. Elastography was performed at multiple frequencies between 400 and 1200 Hz. After 3D-direct inversion, storage modulus (G'), phase angle (ϕ), wave speed and the power law exponent (y) were computed. No significant changes in G' and ϕ were detected. Both α-Syn and Aβ inclusions showed significantly higher y values than control inclusions (P = 0.005) but did not differ between each other. The current phantom study highlighted a specific biomechanical effect of α-Syn and Aβ aggregates, which was better captured with the power law exponent derived from multi-frequency MRE than with single frequency-derived parameters.
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Affiliation(s)
- Mathilde Bigot
- Université de Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, Lyon, France
| | - Fabien Chauveau
- Université de Lyon, Lyon Neuroscience Research Center, CNRS UMR 5292, INSERM U1028, Université Claude Bernard Lyon 1, Lyon, France
| | - Camille Amaz
- Centre D'Investigation Clinique de Lyon, Hôpital Louis Pradel, Hospices Civils de Lyon, Lyon, France
| | - Ralph Sinkus
- INSERM U 1148, Laboratory of Vascular Translational Science, X. Bichat Hospital University Paris Diderot, Paris, France
| | - Olivier Beuf
- Université de Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, Lyon, France
| | - Simon A Lambert
- Université de Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, UJM-Saint Etienne, CNRS, Inserm, CREATIS UMR 5220, U1206, Lyon, France
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22
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Abstract
A rising wave of technologies and instruments are enabling more labs and clinics to make a variety of measurements related to tissue viscoelastic properties. These instruments include elastography imaging scanners, rheological shear viscometers, and a variety of calibrated stress-strain analyzers. From these many sources of disparate data, a common step in analyzing results is to fit the measurements of tissue response to some viscoelastic model. In the best scenario, this places the measurements within a theoretical framework and enables meaningful comparisons of the parameters against other types of tissues. However, there is a large set of established rheological models, even within the class of linear, causal, viscoelastic solid models, so which of these should be chosen? Is it simply a matter of best fit to a minimum mean squared error of the model to several data points? We argue that the long history of biomechanics, including the concept of the extended relaxation spectrum, along with data collected from viscoelastic soft tissues over an extended range of times and frequencies, and the theoretical framework of multiple relaxation models which model the multi-scale nature of physical tissues, all lead to the conclusion that fractional derivative models represent the most succinct and meaningful models of soft tissue viscoelastic behavior. These arguments are presented with the goal of clarifying some distinctions between, and consequences of, some of the most commonly used models, and with the longer term goal of reaching a consensus among different sub-fields in acoustics, biomechanics, and elastography that have common interests in comparing tissue measurements.
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Affiliation(s)
- K J Parker
- Department of Electrical and Computer Engineering, University of Rochester, 724 Computer Studies Building, Box 270231, Rochester, NY 14627, United States of America. Author to whom any correspondence should be addressed
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23
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Holm S. Spring-damper equivalents of the fractional, poroelastic, and poroviscoelastic models for elastography. NMR IN BIOMEDICINE 2018; 31:e3854. [PMID: 29178340 PMCID: PMC6175325 DOI: 10.1002/nbm.3854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 09/05/2017] [Accepted: 09/29/2017] [Indexed: 06/07/2023]
Abstract
In MR elastography, it is common to use an elastic model for the tissue's response in order to interpret the results properly. More complex models, such as viscoelastic, fractional viscoelastic, poroelastic, or poroviscoelastic ones, are also used. These models appear at first sight to be very different, but here it is shown that they may all be expressed in terms of elementary viscoelastic models. For a medium expressed with fractional models, many elementary spring-damper combinations are added, each of them weighted according to a long-tailed distribution of time constants or relaxation frequencies. This may open up a more physical interpretation of fractional models. The shear-wave component of the poroelastic model is shown to be modeled exactly by a three-component Zener model. The extended poroviscoelastic model is found to be equivalent to what is called a non-standard four-parameter model. Accordingly, the large number of parameters in the porous models can be reduced to the same number as in their viscoelastic equivalents. While the individual displacements from the solid and fluid parts cannot be measured individually, the main use of the poro(visco)elastic models is therefore as a physics-based method for determining parameters in a viscoelastic model.
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Affiliation(s)
- Sverre Holm
- Department of InformaticsUniversity of OsloOsloNorway
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