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Wang R, Wang Y, Qiu S, Ma S, Yan F, Yang GZ, Li R, Feng Y. A Comparative Study of Three Systems for Liver Magnetic Resonance Elastography. J Magn Reson Imaging 2024. [PMID: 38449389 DOI: 10.1002/jmri.29335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 02/21/2024] [Accepted: 02/21/2024] [Indexed: 03/08/2024] Open
Abstract
BACKGROUND Different MR elastography (MRE) systems may produce different stiffness measurements, making direct comparison difficult in multi-center investigations. PURPOSE To assess the repeatability and reproducibility of liver stiffness measured by three typical MRE systems. STUDY TYPE Prospective. POPULATION/PHANTOMS Thirty volunteers without liver disease history (20 males, aged 21-28)/5 gel phantoms. FIELD STRENGTH/SEQUENCE 3.0 T United Imaging Healthcare (UIH), 1.5 T Siemens Healthcare, 3.0 T General Electric Healthcare (GE)/Echo planar imaging-based MRE sequence. ASSESSMENT Wave images of volunteers and phantoms were acquired by three MRE systems. Tissue stiffness was evaluated by two observers, while phantom stiffness was assessed automatically by code. The reproducibility across three MRE systems was quantified based on the mean stiffness of each volunteer and phantom. STATISTICAL TESTS Intraclass correlation coefficients (ICC), coefficients of variation (CV), and Bland-Altman analyses were used to assess the interobserver reproducibility, the interscan repeatability, and the intersystem reproducibility. Paired t-tests were performed to assess the interobserver and interscan variation. Friedman tests with Dunn's multiple comparison correction were performed to assess the intersystem variation. P values less than 0.05 indicated significant difference. RESULTS The reproducibility of stiffness measured by the two observers demonstrated consistency with ICC > 0.92, CV < 4.32%, Mean bias < 2.23%, and P > 0.06. The repeatability of measurements obtained using the electromagnetic system for the liver revealed ICC > 0.96, CV < 3.86%, Mean bias < 0.19%, P > 0.90. When considering the range of reproducibility across the three systems for liver evaluations, results ranged with ICCs from 0.70 to 0.87, CVs from 6.46% to 10.99%, and Mean biases between 1.89% and 6.30%. Phantom studies showed similar results. The values of measured stiffness differed across all three systems significantly. DATA CONCLUSION Liver stiffness values measured from different MRE systems can be different, but the measurements across the three MRE systems produced consistent results with excellent reproducibility. EVIDENCE LEVEL 1 TECHNICAL EFFICACY: Stage 2.
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Affiliation(s)
- Runke Wang
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai, China
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy (NERC-AMRT), Shanghai Jiao Tong University, Shanghai, China
| | - Yikun Wang
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Faculty of Medical Imaging Technology, College of Health Science and Technology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Suhao Qiu
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai, China
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy (NERC-AMRT), Shanghai Jiao Tong University, Shanghai, China
| | - Shengyuan Ma
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai, China
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy (NERC-AMRT), Shanghai Jiao Tong University, Shanghai, China
| | - Fuhua Yan
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Faculty of Medical Imaging Technology, College of Health Science and Technology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Guang-Zhong Yang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai, China
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy (NERC-AMRT), Shanghai Jiao Tong University, Shanghai, China
| | - Ruokun Li
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- Faculty of Medical Imaging Technology, College of Health Science and Technology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yuan Feng
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Jiao Tong University, Shanghai, China
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Institute of Medical Robotics, Shanghai Jiao Tong University, Shanghai, China
- National Engineering Research Center of Advanced Magnetic Resonance Technologies for Diagnosis and Therapy (NERC-AMRT), Shanghai Jiao Tong University, Shanghai, China
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Lin H, Qiu S, Yang Y, Yang C, Shen Z, Chen Y, Zhang Z, Feng Y, Yan F. Three-dimensional magnetic resonance elastography combining proton-density fat fraction precisely identifies metabolic dysfunction-associated steatohepatitis with significant fibrosis. Magn Reson Imaging 2023; 104:1-8. [PMID: 37553044 DOI: 10.1016/j.mri.2023.07.017] [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: 06/15/2023] [Revised: 07/30/2023] [Accepted: 07/31/2023] [Indexed: 08/10/2023]
Abstract
PURPOSE Patients with metabolic dysfunction-associated steatohepatitis (MASH) and significant fibrosis (fibrosis stage≥2), known as Fibro-MASH, are at increased risk of liver-related outcomes and lower rates of spontaneous disease regression. The aim was to investigate three-dimensional MR elastography (3D-MRE) combining proton-density fat fraction (PDFF) as a means of identifying Fibro-MASH. METHODS Forty-eight New Zealand rabbits were fed a high-fat/cholesterol or standard diet to obtain different disease activity and fibrosis stages. Shear stiffness (SS) and Damping Ratio (DR) were derived from 3D-MRE, whereas PDFF was from a volumetric 3D imaging sequence. Steatosis grade, metabolic dysfunction-associated steatotic liver disease activity score (MAS), and fibrosis stage were diagnosed histologically. Serum markers of fibrosis and inflammation were also measured. Correlation and comparison analysis, Receiver operating characteristic curves (ROC), Delong test, logistic regression analysis, and Net reclassification improvement (NRI) were performed. RESULTS PDFF correlated with steatosis grade (rho = 0.853). SS increased with developed liver fibrosis (rho = 0.837). DR correlated with MAS grade (rho = 0.678). The areas under the ROC (AUROCs) of SS for fibrosis grading were 0.961 and 0.953 for ≥F2, and ≥ F3, respectively. All the biochemical parameters were considered but excluded from the logistic regression analysis to identify Fibro-MASH. FF, SS, and DR were finally included in the further analysis. The three-parameter model combining PDFF, SS, and DR showed significant improvement in NRI over the model combining SS and PDFF (AUROC 0.973 vs. 0.906, P = 0.081; NRI 0.28, P < 0.05). CONCLUSION 3D-MRE combining PDFF may characterize the state of fat content, disease activity and fibrosis, thus precisely identify Fibro-MASH.
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Affiliation(s)
- Huimin Lin
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Suhao Qiu
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.
| | - Yanzhao Yang
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Chunxue Yang
- Department of Pathology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Zhehan Shen
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Yu Chen
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.
| | - Zhihan Zhang
- Department of Pathology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Yuan Feng
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.
| | - Fuhua Yan
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China; School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China.
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Li N, Zhang X, Zhou J, Li W, Shu X, Wu Y, Long M. Multiscale biomechanics and mechanotransduction from liver fibrosis to cancer. Adv Drug Deliv Rev 2022; 188:114448. [PMID: 35820602 DOI: 10.1016/j.addr.2022.114448] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 05/08/2022] [Accepted: 07/06/2022] [Indexed: 02/06/2023]
Abstract
A growing body of multiscale biomechanical studies has been proposed to highlight the mechanical cues in the development of hepatic fibrosis and cancer. At the cellular level, changes in mechanical microenvironment induce phenotypic and functional alterations of hepatic cells, initiating a positive feedback loop that promotes liver fibrogenesis and hepatocarcinogenesis. Tumor mechanical microenvironment of hepatocellular carcinoma facilitates tumor cell growth and metastasis, and hinders the drug delivery and immunotherapy. At the molecular level, mechanical forces are sensed and transmitted into hepatic cells via allosteric activation of mechanoreceptors on the cell membrane, leading to the activation of various mechanotransduction pathways including integrin and YAP signaling and then regulating cell function. Thus, the application of mechanomedicine concept in the treatment of liver diseases is promising for rational design and cell-specific delivery of therapeutic drugs. This review mainly discusses the correlation between biomechanical cues and liver diseases from the viewpoint of mechanobiology.
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Affiliation(s)
- Ning Li
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China; School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaoyu Zhang
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China; School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jin Zhou
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wang Li
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China; School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinyu Shu
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China; School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yi Wu
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China; School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mian Long
- Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China; School of Engineering Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
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Triolo E, Khegai O, Ozkaya E, Rossi N, Alipour A, Fleysher L, Balchandani P, Kurt M. Design, Construction, and Implementation of a Magnetic Resonance Elastography Actuator for Research Purposes. Curr Protoc 2022; 2:e379. [PMID: 35286023 PMCID: PMC9517172 DOI: 10.1002/cpz1.379] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Magnetic resonance elastography (MRE) is a technique for determining the mechanical response of soft materials using applied harmonic deformation of the material and a motion-sensitive magnetic resonance imaging sequence. This technique can elucidate significant information about the health and development of human tissue such as liver and brain, and has been used on phantom models (e.g., agar, silicone) to determine their suitability for use as a mechanical surrogate for human tissues in experimental models. The applied harmonic deformation used in MRE is generated by an actuator, transmitted in bursts of a specified duration, and synchronized with the magnetic resonance signal excitation. These actuators are most often a pneumatic design (common for human tissues or phantoms) or a piezoelectric design (common for small animal tissues or phantoms). Here, we describe how to design and assemble both a pneumatic and a piezoelectric MRE actuator for research purposes. For each of these actuator types, we discuss displacement requirements, end-effector options and challenges, electronics and electronic-driving requirements and considerations, and full MRE implementation. We also discuss how to choose the actuator type, size, and power based on the intended material and use. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Design, construction, and implementation of a convertible pneumatic MRE actuator for use with tissues and phantom models Basic Protocol 2: Design, construction, and implementation of a piezoelectric MRE actuator for localized excitation in phantom models.
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Affiliation(s)
- E.R. Triolo
- University of Washington, Dept. of Mechanical Engineering (3900 E Stevens Way NE Seattle, WA 98195)
| | - O. Khegai
- Icahn School of Medicine at Mount Sinai, BioMedical Engineering and Imaging Institute (1470 Madison Ave, New York City, NY 10029)
| | - E. Ozkaya
- Icahn School of Medicine at Mount Sinai, BioMedical Engineering and Imaging Institute (1470 Madison Ave, New York City, NY 10029)
| | - N. Rossi
- Stevens Institute of Technology, Dept. of Mechanical Engineering (1 Castle Point Terrace, Hoboken, NJ 07030)
| | - A. Alipour
- Icahn School of Medicine at Mount Sinai, BioMedical Engineering and Imaging Institute (1470 Madison Ave, New York City, NY 10029)
| | - L. Fleysher
- Icahn School of Medicine at Mount Sinai, BioMedical Engineering and Imaging Institute (1470 Madison Ave, New York City, NY 10029)
| | - P. Balchandani
- Icahn School of Medicine at Mount Sinai, BioMedical Engineering and Imaging Institute (1470 Madison Ave, New York City, NY 10029)
| | - M. Kurt
- University of Washington, Dept. of Mechanical Engineering (3900 E Stevens Way NE Seattle, WA 98195)
- Icahn School of Medicine at Mount Sinai, BioMedical Engineering and Imaging Institute (1470 Madison Ave, New York City, NY 10029)
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Wang R, Chen Y, Li R, Qiu S, Zhang Z, Yan F, Feng Y. Fast magnetic resonance elastography with multiphase radial encoding and harmonic motion sparsity based reconstruction. Phys Med Biol 2022; 67. [DOI: 10.1088/1361-6560/ac4a42] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 01/11/2022] [Indexed: 11/12/2022]
Abstract
Abstract
Objective. To achieve fast magnetic resonance elastography (MRE) at a low frequency for better shear modulus estimation of the brain. Approach. We proposed a multiphase radial DENSE MRE (MRD-MRE) sequence and an improved GRASP algorithm utilizing the sparsity of the harmonic motion (SH-GRASP) for fast MRE at 20 Hz. For the MRD-MRE sequence, the initial position encoded by spatial modulation of magnetization (SPAMM) was decoded by an arbitrary number of readout blocks without increasing the number of phase offsets. Based on the harmonic motion, a modified total variation and temporal Fourier transform were introduced to utilize the sparsity in the temporal domain. Both phantom and brain experiments were carried out and compared with that from multiphase Cartesian DENSE-MRE (MCD-MRE), and conventional gradient echo sequence (GRE-MRE). Reconstruction performance was also compared with GRASP and compressed sensing. Main results. Results showed the scanning time of a fully sampled image with four phase offsets for MRD-MRE was only 1/5 of that from GRE-MRE. The wave patterns and estimated stiffness maps were similar to those from MCD-MRE and GRE-MRE. With SH-GRASP, the total scan time could be shortened by additional 4 folds, achieving a total acceleration factor of 20. Better metric values were also obtained using SH-GRASP for reconstruction compared with other algorithms. Significance. The MRD-MRE sequence and SH-GRASP algorithm can be used either in combination or independently to accelerate MRE, showing the potentials for imaging the brain as well as other organs.
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He Z, Zhu YN, Qiu S, Wang T, Zhang C, Sun B, Zhang X, Feng Y. Low-Rank and Framelet Based Sparsity Decomposition for Interventional MRI Reconstruction. IEEE Trans Biomed Eng 2022; 69:2294-2304. [PMID: 35015631 DOI: 10.1109/tbme.2022.3142129] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Interventional MRI (i-MRI) is crucial for MR image-guided therapy. Current image reconstruction methods for dynamic MR imaging are mostly retrospective that may not be suitable for i-MRI in real-time. Therefore, an algorithm to reconstruct images without a temporal pattern as in dynamic imaging is needed for i-MRI. METHODS We proposed a low-rank and sparsity (LS) decomposition algorithm with framelet transform to reconstruct the interventional feature with a high temporal resolution. Different from the existing LS based algorithm, the spatial sparsity of both the low-rank and sparsity components was used. We also used a primal dual fixed point (PDFP) method for optimization of the objective function to avoid solving sub-problems. Intervention experiments with gelatin and brain phantoms were carried out for validation. RESULTS The LS decomposition with framelet transform and PDFP could provide the best reconstruction performance compared with those without. Satisfying reconstruction results were obtained with only 10 radial spokes for a temporal resolution of 60 ms. CONCLUSION AND SIGNIFICANCE The proposed method has the potential for i-MRI in many different application scenarios.
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Tavakoli J, Geargeflia S, Tipper JL, Diwan AD. Magnetic resonance elastography: A non-invasive biomarker for low back pain studies. BIOMEDICAL ENGINEERING ADVANCES 2021. [DOI: 10.1016/j.bea.2021.100014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Qiu S, He Z, Wang R, Li R, Zhang A, Yan F, Feng Y. An electromagnetic actuator for brain magnetic resonance elastography with high frequency accuracy. NMR IN BIOMEDICINE 2021; 34:e4592. [PMID: 34291510 DOI: 10.1002/nbm.4592] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 06/07/2021] [Accepted: 07/06/2021] [Indexed: 06/13/2023]
Abstract
Our goal is to design, test and verify an electromagnetic actuator for brain magnetic resonance elastography (MRE). We proposed a grappler-shaped design that can transmit stable vibrations into the brain. To validate its performance, simulations were carried out to ensure the electromagnetic field generated by the actuator did not interfere with the B0 field. The actuation vibration spectrum was analyzed to verify the actuation accuracy. Phantom and volunteer experiments were carried out to evaluate the performance of the actuator. Simulation of the magnetic field showed that the proposed actuator has a fringe field of less than 3 G in the imaging region. The phantom experiments showed that the proposed actuator did not interfere with the routine imaging sequences. The measured vibration spectra demonstrated that the frequency offset was about one third that of a pneumatic device and the transmission efficiency was three times higher. The shear moduli estimated from brain MRE were consistent with those from the literature. The actuation frequency of the proposed actuator has less frequency offset and off-center frequency components compared with the pneumatic counterpart. The whole actuator weighted only 980 g. The actuator can carry out multifrequency MRE on the brain with high accuracy. It is easy to use, comfortable for the patient and portable.
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Affiliation(s)
- Suhao Qiu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Zhao He
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Runke Wang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Ruokun Li
- Department of Radiology, Ruijin Hospital, Shanghai, China
| | - Aili Zhang
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Fuhua Yan
- Department of Radiology, Ruijin Hospital, Shanghai, China
| | - Yuan Feng
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
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Guidetti M, Lorgna G, Hammersly M, Lewis P, Klatt D, Vena P, Shah R, Royston TJ. Anisotropic composite material phantom to improve skeletal muscle characterization using magnetic resonance elastography. J Mech Behav Biomed Mater 2018; 89:199-208. [PMID: 30292169 DOI: 10.1016/j.jmbbm.2018.09.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 09/23/2018] [Accepted: 09/24/2018] [Indexed: 12/12/2022]
Abstract
The presence and progression of neuromuscular pathology, including spasticity, Duchenne's muscular dystrophy and hyperthyroidism, has been correlated with changes in the intrinsic mechanical properties of skeletal muscle tissue. Tools for noninvasively measuring and monitoring these properties, such as Magnetic Resonance Elastography (MRE), could benefit basic research into understanding neuromuscular pathologies, as well as translational research to develop therapies, by providing a means of assessing and tracking their efficacy. Dynamic elastography methods for noninvasive measurement of tissue mechanical properties have been under development for nearly three decades. Much of the technological development to date, for both Ultrasound (US)-based and Magnetic Resonance Imaging (MRI)-based strategies, has been grounded in assumptions of local homogeneity and isotropy. Striated skeletal and cardiac muscle, as well as brain white matter and soft tissue in some other organ regions, exhibit a fibrous microstructure which entails heterogeneity and anisotropic response; as one seeks to improve the accuracy and resolution in mechanical property assessment, heterogeneity and anisotropy need to be accounted for in order to optimize both the dynamic elastography experimental protocol and the interpretation of the measurements. Advances in elastography methodology at every step have been aided by the use of tissue-mimicking phantoms. The aim of the present study was to develop and characterize a heterogeneous composite phantom design with uniform controllable anisotropic properties meant to be comparable to the frequency-dependent anisotropic properties of skeletal muscle. MRE experiments and computational finite element (FE) studies were conducted on a novel 3D-printed composite phantom design. The displacement maps obtained from simulation and experiment show the same elliptical shaped wavefronts elongated in the plane where the structure presents higher shear modulus. The model exhibits a degree of anisotropy in line with literature data from skeletal muscle tissue MRE experiments. FE simulations of the MRE experiments provide insight into proper interpretation of experimental measurements, and help to quantify the importance of heterogeneity in the anisotropic material at different scales.
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Affiliation(s)
- Martina Guidetti
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, 851 South Mogan Street, 212 SEO, Chicago, IL 60607-7052, USA.
| | - Gloria Lorgna
- Department of Chemistry, Materials and Chemical Engineering Giulio Natta, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milan, Italy.
| | - Margaret Hammersly
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA; Simpson Querrey Institute, Northwestern University, Chicago, IL, USA
| | - Phillip Lewis
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA; Simpson Querrey Institute, Northwestern University, Chicago, IL, USA
| | - Dieter Klatt
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, 851 South Mogan Street, 212 SEO, Chicago, IL 60607-7052, USA.
| | - Pasquale Vena
- Department of Chemistry, Materials and Chemical Engineering Giulio Natta, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milan, Italy.
| | - Ramille Shah
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, 851 South Mogan Street, 212 SEO, Chicago, IL 60607-7052, USA; Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA; Simpson Querrey Institute, Northwestern University, Chicago, IL, USA
| | - Thomas J Royston
- Richard and Loan Hill Department of Bioengineering, University of Illinois at Chicago, 851 South Mogan Street, 212 SEO, Chicago, IL 60607-7052, USA.
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