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Haam JH, Lee YK, Suh E, Kim YS. Characteristics of Urine Organic Acid Metabolites in Nonalcoholic Fatty Liver Disease Assessed Using Magnetic Resonance Imaging with Elastography in Korean Adults. Diagnostics (Basel) 2022; 12:diagnostics12051199. [PMID: 35626354 PMCID: PMC9140840 DOI: 10.3390/diagnostics12051199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Revised: 05/05/2022] [Accepted: 05/09/2022] [Indexed: 02/01/2023] Open
Abstract
The liver is an essential organ that manufactures energy through various metabolic pathways; thus, exploring the intermediate metabolites in nonalcoholic fatty liver disease (NAFLD) may help discover novel parameters in hepatic steatosis or fibrosis. The present study aimed to investigate the traits of urine organic acid metabolites in participants with hepatic steatosis and fibrosis in nonalcoholic Korean adults. Hepatic steatosis and fibrosis, in 68 men and 65 women, were evaluated using quantification by proton density fat fraction with magnetic resonance (MR) imaging and MR elastography, respectively. Urine metabolites were obtained using a high-performance liquid chromatography–mass spectrometry analysis. The candidate metabolites were included in the logistic regression models for hepatic steatosis and fibrosis. The association between high p-hydroxyphenyllactate levels and hepatic steatosis was not independent of body mass index and Homeostatic Model Assessment-insulin resistance. High ethylmalonate, β-hydroxybutyrate, and sulfate levels were significantly related to a low probability of hepatic fibrosis, independent of covariates. In conclusion, urine metabolites were not related to hepatic steatosis independent of obesity and insulin resistance, while several metabolites were specifically associated with hepatic fibrosis. Further study is required to verify the diagnostic value of the metabolites in a population with wide-spectrum NAFLD.
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Affiliation(s)
- Ji-Hee Haam
- Chaum Life Center, CHA University, Seoul 06062, Korea; (J.-H.H.); (Y.K.L.); (E.S.)
| | - Yun Kyong Lee
- Chaum Life Center, CHA University, Seoul 06062, Korea; (J.-H.H.); (Y.K.L.); (E.S.)
| | - Eunkyung Suh
- Chaum Life Center, CHA University, Seoul 06062, Korea; (J.-H.H.); (Y.K.L.); (E.S.)
| | - Young-Sang Kim
- Department of Family Medicine, CHA Bundang Medical Center, CHA University, Seongnam 13496, Korea
- Correspondence:
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Xu P, Lyu L, Lu X, Hu C, Xu K. Evaluating the Short-Term Clinical Efficacy of Magnetic Resonance Elastography in Patients with Budd-Chiari Syndrome. Acad Radiol 2021; 28 Suppl 1:S179-S183. [PMID: 33663971 DOI: 10.1016/j.acra.2021.02.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/12/2021] [Accepted: 02/14/2021] [Indexed: 12/13/2022]
Abstract
RATIONALE AND OBJECTIVES To investigate the clinical relevance of liver stiffness (LS) in evaluating liver function properties in patients with Budd-Chiari syndrome (BCS) with different severities and LS variation before and after endovascular intervention. MATERIALS AND METHODS Between December 2016 and March 2019, patients with a diagnosis of BCS were considered for enrollment consecutively in our study. Liver function of these patients was classified according to Child-Pugh grading standard before treatment. Liver function parameters were recorded, including albumin, alanine aminotransferase, aspartate aminotransferase, prothrombin time, and total bilirubin. LS was measured with MR elastography (MRE) before and after treatment. Pearson correlation analysis was performed to measure the correlation between LS and liver function-related parameters. Univariate analysis of variance test was used to compare LS and clinical quantitative variables of patients in three different Child-Pugh categories. Paired t test with a significant threshold of p = 0.05 was used to compare LS and pressure gradient of these patients before and after treatment. Correlation analysis between changes in LS and that in pressure gradient was performed by linear regression. RESULTS A total of 43 patients (23 males and 20 females) were finally enrolled in this study. The mean LS in the three groups was 5.67 ± 1.15 kPa (Child-Pugh A), 6.31 ± 1.13 kPa (Child-Pugh B), and 8.27 ± 2.22 kPa (Child-Pugh C), respectively. LS showed significant difference for patients with different Child-Pugh grades (F = 9.536, p < 0.001). Prothrombin time and total bilirubin were positively correlated with LS (p < 0.05). After treatment, mean LS in three groups was 4.83 ± 1.06 kPa, 5.12 ± 0.93, and 7.37 ± 1.96, respectively. LS decreased significantly in all three Child-Pugh grades (p < 0.001 from Child-Pugh A, p < 0.001 from Child-Pugh B, p = 0.009 from Child-Pugh C). The mean pressure gradient before intervention was 17.6 ± 4.9 mm Hg, and 8.7 ± 7.2 mm Hg after the treatment (p < 0.001). The changes in LS were correlated to that in pressure gradients (r = 0.439; r2 = 0.193; p = 0.015). CONCLUSION MR elastography for LS measurement has been demonstrated to act as an effective tool to evaluate liver function, and to monitor the BCS patients in follow-up treatments.
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Affiliation(s)
- Peng Xu
- Department of Radiology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221002, China
| | - Lulu Lyu
- Department of CT and MRI, Xuzhou Central Hospital, Xuzhou, Jiangsu, China
| | - Xin Lu
- Department of Radiology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221002, China
| | - Chunfeng Hu
- Department of Radiology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221002, China
| | - Kai Xu
- Department of Radiology, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221002, China.
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Abstract
Magnetic resonance elastography (MRE) is an emerging noninvasive technique, an alternative to palpation for quantitative assessment of biomechanical properties of tissue. In MRE, tissue stiffness information is obtained by a 3-step process, propagating mechanical waves in the tissues, measuring the wave propagation using modified magnetic resonance (MR) pulse sequences, and generating the quantitative stiffness maps from the MR images. MRE is clinically used in patients with liver diseases, whereas its applications in other organs are still being investigated. At present, the pediatric studies are in the initial stage and preliminary results promise to provide additional information about tissue characteristics.
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Affiliation(s)
- Manjunathan Nanjappa
- Department of Radiology, The Ohio State University Wexner Medical Center, 460 West 12th Avenue, Room No 333 3rd Floor, Columbus, OH 43210, USA
| | - Arunark Kolipaka
- Department of Radiology, The Ohio State Wexner Medical Center, 395 West 12th Avenue, 4th Floor, Columbus, OH 43210, USA.
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Obrzut M, Atamaniuk V, Chen J, Obrzut B, Ehman RL, Cholewa M, Palusińska A, Gutkowski K. Postprandial hepatic stiffness changes on magnetic resonance elastography in healthy volunteers. Sci Rep 2021; 11:19786. [PMID: 34611231 PMCID: PMC8492759 DOI: 10.1038/s41598-021-99243-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 09/14/2021] [Indexed: 11/23/2022] Open
Abstract
Magnetic resonance elastography (MRE) is a reliable noninvasive method for assessment of hepatic stiffness. Liver stiffness is known to be affected by elevated postprandial portal blood flow in patients with chronic liver disease. The goal of this study was to determine whether food intake affects liver stiffness in the absence of known liver disease. We evaluated 100 volunteers (35 men and 65 women) who met inclusion criteria. The subjects had two MRE examinations, first while fasting and then 30 min after a test meal. Fourteen subjects also had two additional MRE exams 1 h 30 min and 2 h 30 min after the meal. Liver stiffness was measured by placing the largest possible polygon ROIs on the four widest liver slices and calculated as a mean of stiffness values from each slice. The correlation of liver stiffness values before and after the meal was assessed using a paired t-test. To evaluate the relationship between the change in postprandial liver stiffness and fasting liver stiffness values, linear regression was performed. The liver stiffness values in the fasting state ranged from 1.84 to 2.82 kPa, with a mean of 2.30 ± 0.23 kPa (95% CI 2.25–2.34). At 30 min after the meal, liver stiffness values ranged from 2.12 to 3.50 kPa, with a mean of 2.70 ± 0.28 kPa (95% CI 2.64–2.75), demonstrating a systematic postprandial increase by 0.40 ± 0.23 kPa (17.7 ± 3.5%). Meal intake significantly increases liver stiffness in healthy individuals, which persists for at least 2 h 30 min. Patients should fast for 3–4 h before MRE examinations to avoid fibrosis overstaging due to postprandial liver stiffness augmentation.
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Affiliation(s)
- Marzanna Obrzut
- Institute of Health Sciences, Medical College, University of Rzeszow, Rzeszow, Poland
| | - Vitaliy Atamaniuk
- Department of Biophysics, College of Natural Sciences, Institute of Physics, University of Rzeszow, aleja Tadeusza Rejtana 16C, 35-959, Rzeszow, Poland.
| | - Jun Chen
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | - Bogdan Obrzut
- Department of Obstetrics and Gynecology, Institute of Medical Sciences, Medical College, University of Rzeszow, Rzeszow, Poland
| | | | - Marian Cholewa
- Department of Biophysics, College of Natural Sciences, Institute of Physics, University of Rzeszow, aleja Tadeusza Rejtana 16C, 35-959, Rzeszow, Poland
| | - Agnieszka Palusińska
- Department of Internal Medicine and Nephrodiabetology, Medical University of Lodz, Lodz, Poland
| | - Krzysztof Gutkowski
- Institute of Medical Sciences, Medical College, University of Rzeszow, Rzeszow, Poland
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Effect of breath holding at the end of the inspiration and expiration phases on liver stiffness measured by 2D-MR elastography. Abdom Radiol (NY) 2021; 46:2516-2526. [PMID: 33386913 DOI: 10.1007/s00261-020-02893-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/27/2020] [Accepted: 12/04/2020] [Indexed: 02/07/2023]
Abstract
PURPOSE Evaluate the effect of breath holding at the end of the inspiration and expiration phases on the measurement of liver stiffness by 2D-MR elastography (MRE). METHODS The study included 61 subjects, of which 31 subjects were pathologically confirmed liver fibrosis patients [liver fibrosis group (LFG)] and 30 healthy subjects [healthy group (HG)]. MRE was used to measure the liver stiffness of subjects in inspiration breath-hold (IBH) and expiration breath-hold (EBH) states. RESULTS In IBH and EBH states, the liver stiffness measured by MRE was not significantly different in the HG (P = 0.125, > 0.05), while the LFG showed a significant difference (P <0.001). Also, a significant difference was observed between the change values in the mild/moderate fibrosis group (MFG) and advanced fibrosis group (AFG) (P = 0.005, < 0.05). CONCLUSIONS The liver stiffness values in patients with liver fibrosis were affected by breath-holding states. The higher the stage of liver fibrosis, the greater the change in liver stiffness values, but no significant difference was observed between liver stiffness values in healthy subjects under the two breath-holding conditions. Different breath-holding states are factors influencing liver fibrosis stiffness measured by MRE, which should be given due attention in both clinical and research contexts.
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Abstract
Magnetic resonance elastography (MRE) is an emerging imaging modality that maps the elastic properties of tissue such as the shear modulus. It allows for noninvasive assessment of stiffness, which is a surrogate for fibrosis. MRE has been shown to accurately distinguish absent or low stage fibrosis from high stage fibrosis, primarily in the liver. Like other elasticity imaging modalities, it follows the general steps of elastography: (1) apply a known cyclic mechanical vibration to the tissue; (2) measure the internal tissue displacements caused by the mechanical wave using magnetic resonance phase encoding method; and (3) infer the mechanical properties from the measured mechanical response (displacement), by generating a simplified displacement map. The generated map is called an elastogram.While the key interest of MRE has traditionally been in its application to liver, where in humans it is FDA approved and commercially available for clinical use to noninvasively assess degree of fibrosis, this is an area of active research and there are novel upcoming applications in brain, kidney, pancreas, spleen, heart, lungs, and so on. A detailed review of all the efforts is beyond the scope of this chapter, but a few specific examples are provided. Recent application of MRE for noninvasive evaluation of renal fibrosis has great potential for noninvasive assessment in patients with chronic kidney diseases. Development and applications of MRE in preclinical models is necessary primarily to validate the measurement against "gold-standard" invasive methods, to better understand physiology and pathophysiology, and to evaluate novel interventions. Application of MRE acquisitions in preclinical settings involves challenges in terms of available hardware, logistics, and data acquisition. This chapter will introduce the concepts of MRE and provide some illustrative applications.This publication is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction chapter is complemented by another separate chapter describing the experimental protocol and data analysis.
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Affiliation(s)
- Suraj D Serai
- Department of Radiology, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA.
| | - Meng Yin
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
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Plaikner M, Kremser C, Viveiros A, Zoller H, Henninger B. [Magnetic resonance elastography of the liver : Worth knowing for clinical routine]. Radiologe 2020; 60:966-978. [PMID: 32399783 DOI: 10.1007/s00117-020-00690-6] [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] [Indexed: 11/27/2022]
Abstract
BACKGROUND Magnetic resonance elastography (MRE) is a noninvasive, quantitative, MRI-based method to evaluate liver stiffness. Beside biopsy and ultrasound elastography, this imaging method plays in many places a significant role in the detection and additive characterization of chronic liver disease. OBJECTIVES, MATERIALS AND METHODS Based on the literature, a brief review of the underlying method and the commercially available products is given. Furthermore, the practical procedure, the analysis, and the interpretation of clinically relevant questions are illustrated and a comparison with ultrasound elastography is provided. RESULTS This relative "young" MRI method allows extensive evaluation of mechanical properties of the liver and is an important diagnostic tool especially in follow-up examinations. The MRE of the liver is with a maximum technical failure rate of 5.8% a robust technique with high accuracy and an excellent re-test reliability as well as intra- and interobserver reproducibility. There is a high diagnostic certainty within the framework of most important clinical indications, the quantification of fibrosis, and with a very good correlation with the "gold standard" biopsy. CONCLUSION Based on its rising clinical relevance and the broad usage, MRE of the liver is increasingly used in many centers and in routine liver protocols. Therefore, basic knowledge of this method is essential for every radiologist.
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Affiliation(s)
- Michaela Plaikner
- Radiologie, Medizinische Universität Innsbruck, Anichstraße 35, 6020, Innsbruck, Österreich.
| | - Christian Kremser
- Radiologie, Medizinische Universität Innsbruck, Anichstraße 35, 6020, Innsbruck, Österreich
| | - André Viveiros
- Innere Medizin I, Medizinische Universität Innsbruck, Anichstraße 35, 6020, Innsbruck, Österreich
| | - Heinz Zoller
- Innere Medizin I, Medizinische Universität Innsbruck, Anichstraße 35, 6020, Innsbruck, Österreich
| | - Benjamin Henninger
- Radiologie, Medizinische Universität Innsbruck, Anichstraße 35, 6020, Innsbruck, Österreich
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Serai SD, Trout AT. Can MR elastography be used to measure liver stiffness in patients with iron overload? Abdom Radiol (NY) 2019; 44:104-109. [PMID: 30066167 DOI: 10.1007/s00261-018-1723-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Untreated hepatic iron overload causes hepatic fibrosis and cirrhosis and can predispose to hepatocellular carcinoma. MR elastography (MRE) provides a non-invasive means to measure liver stiffness, which correlates with liver fibrosis but standard gradient recalled echo (GRE)-based MRE techniques fail in patients with high iron due to very low hepatic signal. Short echo time (TE) 2D spin echo echoplanar imaging (SE-EPI)-based MRE may allow measurement of stiffness in the iron loaded liver. The purpose of this study was to describe the use of such an MRE sequence in patients undergoing liver iron quantification by MRI. In our preliminary study of 43 patients with mean LIC of 9.3 mg/g (range 1.8-21.5 mg/g), liver stiffness measurements could be made in 77% (33/43) of patients with a short TE, SE-EPI based MRE sequence. On average, mean LIC in patients with failed MRE was higher than in those with successful MRE (15.9 mg/g dry weight vs. 7.3 mg/g), but a cut-off value for successful MRE could not be established. Seven patients (21% of those with successful MRE) had liver stiffness values suggestive of the presence of significant fibrosis (> 2.49 kPa). A short TE, SE-EPI based MR elastography sequence allows successful measurement of liver stiffness in a majority of patients with liver iron loading, potentially allowing non-invasive screening for fibrosis.
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Neumann W, Bichert A, Fleischhauer J, Stern A, Figuli R, Wilhelm M, Schad LR, Zöllner FG. A novel 3D printed mechanical actuator using centrifugal force for magnetic resonance elastography: Initial results in an anthropomorphic prostate phantom. PLoS One 2018; 13:e0205442. [PMID: 30296308 PMCID: PMC6175527 DOI: 10.1371/journal.pone.0205442] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 09/25/2018] [Indexed: 12/12/2022] Open
Abstract
This work demonstrates a new method for the generation of mechanical shear wave during magnetic resonance elastography (MRE) that creates greater forces at higher vibrational frequencies as opposed to conventionally used pneumatic transducers. We developed an MR-compatible pneumatic turbine with an eccentric mass that creates a sinusoidal centrifugal force. The turbine was assessed with respect to its technical parameters and evaluated for MRE on a custom-made anthropomorphic prostate phantom. The silicone-based tissue-mimicking materials of the phantom were selected with regard to their complex shear moduli examined by rheometric testing. The tissue-mimicking materials closely matched human soft tissue elasticity values with a complex shear modulus ranging from 3.21 kPa to 7.29 kPa. We acquired MRE images on this phantom at 3 T with actuation frequencies of 50, 60 Hz, 70 Hz, and 80 Hz. The turbine generated vibrational wave amplitudes sufficiently large to entirely penetrate the phantoms during the feasibility study. Increased wave length in the stiffer inclusions compared to softer background material were detected. Our initial results suggest that silicone-based phantoms are useful for the evaluation of elasticities during MRE. Furthermore, our turbine seems suitable for the mechanical assessment of soft tissue during MRE.
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Affiliation(s)
- Wiebke Neumann
- Department of Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Andreas Bichert
- Department of Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Jonas Fleischhauer
- Department of Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Antonia Stern
- Department of Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Roxana Figuli
- Institute for Chemical Technology and Polymer Chemistry of Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Manfred Wilhelm
- Institute for Chemical Technology and Polymer Chemistry of Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Lothar R. Schad
- Department of Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Frank G. Zöllner
- Department of Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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Capilnasiu A, Hadjicharalambous M, Fovargue D, Patel D, Holub O, Bilston L, Screen H, Sinkus R, Nordsletten D. Magnetic resonance elastography in nonlinear viscoelastic materials under load. Biomech Model Mechanobiol 2018; 18:111-135. [PMID: 30151814 PMCID: PMC6373278 DOI: 10.1007/s10237-018-1072-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 08/10/2018] [Indexed: 12/27/2022]
Abstract
Characterisation of soft tissue mechanical properties is a topic of increasing interest in translational and clinical research. Magnetic resonance elastography (MRE) has been used in this context to assess the mechanical properties of tissues in vivo noninvasively. Typically, these analyses rely on linear viscoelastic wave equations to assess material properties from measured wave dynamics. However, deformations that occur in some tissues (e.g. liver during respiration, heart during the cardiac cycle, or external compression during a breast exam) can yield loading bias, complicating the interpretation of tissue stiffness from MRE measurements. In this paper, it is shown how combined knowledge of a material's rheology and loading state can be used to eliminate loading bias and enable interpretation of intrinsic (unloaded) stiffness properties. Equations are derived utilising perturbation theory and Cauchy's equations of motion to demonstrate the impact of loading state on periodic steady-state wave behaviour in nonlinear viscoelastic materials. These equations demonstrate how loading bias yields apparent material stiffening, softening and anisotropy. MRE sensitivity to deformation is demonstrated in an experimental phantom, showing a loading bias of up to twofold. From an unbiased stiffness of [Formula: see text] Pa in unloaded state, the biased stiffness increases to 9767.5 [Formula: see text]1949.9 Pa under a load of [Formula: see text] 34% uniaxial compression. Integrating knowledge of phantom loading and rheology into a novel MRE reconstruction, it is shown that it is possible to characterise intrinsic material characteristics, eliminating the loading bias from MRE data. The framework introduced and demonstrated in phantoms illustrates a pathway that can be translated and applied to MRE in complex deforming tissues. This would contribute to a better assessment of material properties in soft tissues employing elastography.
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Affiliation(s)
- Adela Capilnasiu
- Division of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.
| | - Myrianthi Hadjicharalambous
- Division of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.,KIOS Research and Innovation Centre of Excellence, University of Cyprus, Nicosia, Cyprus
| | - Daniel Fovargue
- Division of Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Dharmesh Patel
- Institute of Bioengineering, Queen Mary University of London, London, UK
| | - Ondrej Holub
- 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
| | - Hazel Screen
- Institute of Bioengineering, Queen Mary University of London, London, UK
| | - 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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Neumann W, Schad LR, Zollner FG. A novel 3D-printed mechanical actuator using centrifugal force for magnetic resonance elastography. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2018; 2017:3541-3544. [PMID: 29060662 DOI: 10.1109/embc.2017.8037621] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Magnetic resonance elastography (MRE) is a technique for the quantification of tissue stiffness during MR examinations. It requires consistent methods for mechanical shear wave induction to the region of interest in the human body to reliably quantify elastic properties of soft tissues. This work proposes a novel 3D-printed mechanical actuator using the principle of centrifugal force for wave induction. The driver consists of a 3D-printed turbine vibrator powered by compressed air (located inside the scanner room) and an active driver controlling the pressure of inflowing air (placed outside the scanner room). The generated force of the proposed actuator increases for higher actuation frequencies as opposed to conventionally used air cushions. There, the displacement amplitude decreases with increasing actuation frequency resulting in a smaller signal-to-noise ratio. An initial phantom study is presented which demonstrates the feasibility of the actuator for MRE. The wave-actuation frequency was regulated in a range between 15 Hz and 60 Hz for force measurements and proved sufficiently stable (± 0.3 Hz) for any given nominal frequency. The generated forces depend on the weight of the eccentric unbalance within the turbine and ranged between 0.67 N to 2.70 N (for 15 Hz) and 3.09 N to 7.77 N (for 60 Hz). Therefore, the generated force of the presented actuator increases with rotational speed of the turbine and offers an elegant solution for sufficiently large wave actuation at higher frequencies. In future work, we will investigate an optimal ratio of the weight of unbalance to the size of turbine for appropriately large but tolerable wave actuation for a given nominal frequency.
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Zhang X, Zhu X, Ferguson CM, Jiang K, Burningham T, Lerman A, Lerman LO. Magnetic resonance elastography can monitor changes in medullary stiffness in response to treatment in the swine ischemic kidney. MAGMA (NEW YORK, N.Y.) 2018; 31:375-382. [PMID: 29289980 PMCID: PMC5976551 DOI: 10.1007/s10334-017-0671-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 12/14/2017] [Accepted: 12/20/2017] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Low-energy shockwave (SW) therapy attenuates damage in the stenotic kidney (STK) caused by atherosclerotic renal artery stenosis (ARAS). We hypothesized that magnetic resonance elastography (MRE) would detect attenuation of fibrosis following SW in unilateral ARAS kidneys. MATERIALS AND METHODS Domestic pigs were randomized to control, unilateral ARAS, and ARAS treated with 6 sessions of SW over 3 consecutive weeks (n = 7 each) starting after 3 weeks of ARAS or sham. Four weeks after SW treatment, renal fibrosis was evaluated with MRE in vivo or trichrome staining ex vivo. Blood pressure, single-kidney renal-blood-flow (RBF) and glomerular-filtration-rate (GFR) were assessed. RESULTS MRE detected increased stiffness in the STK medulla (15.3 ± 2.1 vs. 10.1 ± 0.8 kPa, p < 0.05) that moderately correlated with severity of fibrosis (R2 = 0.501, p < 0.01), but did not identify mild STK cortical or contralateral kidney fibrosis. Trichrome staining showed that medullary fibrosis was increased in ARAS and alleviated by SW (10.4 ± 1.8% vs. 2.9 ± 0.2%, p < 0.01). SW slightly decreased blood pressure and normalized STK RBF and GFR in ARAS. In the contralateral kidney, SW reversed the increase in RBF and GFR. CONCLUSION MRE might be a tool for noninvasive monitoring of medullary fibrosis in response to treatment in kidney disease.
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Affiliation(s)
- Xin Zhang
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Xiangyang Zhu
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | | | - Kai Jiang
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Tyson Burningham
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Amir Lerman
- Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Lilach Orly Lerman
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
- Cardiovascular Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
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13
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Yin M, Glaser KJ, Manduca A, Mounajjed T, Malhi H, Simonetto DA, Wang R, Yang L, Mao SA, Glorioso JM, Elgilani FM, Ward CJ, Harris PC, Nyberg SL, Shah VH, Ehman RL. Distinguishing between Hepatic Inflammation and Fibrosis with MR Elastography. Radiology 2017; 284:694-705. [PMID: 28128707 DOI: 10.1148/radiol.2017160622] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Purpose To investigate the utility of magnetic resonance (MR) elastography-derived mechanical properties in the discrimination of hepatic inflammation and fibrosis in the early stages of chronic liver diseases. Materials and Methods All studies were approved by the institutional animal care and use committee. A total of 187 animals were studied, including 182 mice and five pigs. These animals represented five different liver diseases with a varying combination and extent of hepatic inflammation, fibrosis, congestion, and portal hypertension. Multifrequency three-dimensional MR elastography was performed, and shear stiffness, storage modulus, shear loss modulus, and damping ratio were calculated for all animals. Necroinflammation, fibrosis, and portal pressure were either histologically scored or biochemically and physically quantified in all animals. Two-sided Welch t tests were used to evaluate mean differences between disease and control groups. Spearman correlation analyses were used to evaluate the relationships between mechanical parameters and quantitative fibrosis extent (hydroxyproline concentration) and portal pressure. Results Liver stiffness and storage modulus increased with progressively developed fibrosis and portal hypertension (mean stiffness at 80 Hz and 48-week feeding, 0.51 kPa ± 0.12 in the steatohepatitis group vs 0.29 kPa ± 0.01 in the control group; P = .02). Damping ratio and shear loss modulus can be used to distinguish inflammation from fibrosis at early stages of disease, even before the development of histologically detectable necroinflammation and fibrosis (mean damping ratio at 80 Hz and 20-week feeding, 0.044 ± 0.012 in the steatohepatitis group vs 0.014 ± 0.008 in the control group; P < .001). Damping ratio and liver stiffness vary differently with respect to cause of portal hypertension (ie, congestion- or cirrhosis-induced hypertension). These differentiation abilities have frequency-dependent variations. Conclusion Liver stiffness and damping ratio measurements can extend hepatic MR elastography to potentially enable assessment of necroinflammatory, congestive, and fibrotic processes of chronic liver diseases. © RSNA, 2017 Online supplemental material is available for this article.
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Affiliation(s)
- Meng Yin
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Kevin J Glaser
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Armando Manduca
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Taofic Mounajjed
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Harmeet Malhi
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Douglas A Simonetto
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Ruisi Wang
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Liu Yang
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Shennen A Mao
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Jaime M Glorioso
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Faysal M Elgilani
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Christopher J Ward
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Peter C Harris
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Scott L Nyberg
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Vijay H Shah
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
| | - Richard L Ehman
- From the Departments of Radiology (M.Y., K.J.G., A.M., R.L.E.) and Physiology and Biomedical Engineering (A.M.) and the Divisions of Anatomic Pathology (T.M.), Gastroenterology and Hepatology (H.M., D.A.S., R.W., L.Y., V.H.S.), Transplantation Surgery (S.A.M., J.M.G., F.M.E., S.L.N.), and Nephrology and Hypertension (C.J.W., P.C.H.), Mayo Clinic, 200 First St SW, Rochester, MN 55905
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Zhuang Y, Ding H, Zhang Y, Sun H, Xu C, Wang W. Two-dimensional Shear-Wave Elastography Performance in the Noninvasive Evaluation of Liver Fibrosis in Patients with Chronic Hepatitis B: Comparison with Serum Fibrosis Indexes. Radiology 2016; 283:873-882. [PMID: 27982760 DOI: 10.1148/radiol.2016160131] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Purpose To investigate the value of two-dimensional (2D) shear-wave elastography (SWE) in the assessment of hepatic fibrosis in patients with chronic hepatitis B (CHB) and to compare the diagnostic performance of this modality with that of liver fibrosis indexes. Materials and Methods The ethics committee approved this study, and informed consent was obtained. From July 2015 to May 2016, 539 subjects who underwent partial hepatectomy were divided into groups according to the Scheuer system by using a resected liver specimen. All patients were examined with 2D SWE and underwent preoperative serologic testing to measure liver stiffness and values of serum fibrosis models, which were compared with histologic findings. Performance of noninvasive methods was determined for index (304 patients) and validation (155 patients) cohorts by using areas under the receiver operating characteristic curve (AUCs). Results For association with substantial fibrosis (≥S2), severe fibrosis (≥S3), and cirrhosis (S4) in the index cohort, the optimal cutoff values of liver stiffness were 7.6, 9.2, and 10.4 kPa, respectively, and AUC values were 0.97, 0.96, and 0.98, respectively. The 2D SWE findings, aspartate transaminase-to-platelet ratio index (APRI), fibrosis index based on the four factors (FIB-4), King's score, and Forns index significantly correlated with hepatic fibrosis stages (ρ = 0.88, ρ = 0.41, ρ = 0.40, ρ = 0.43 and ρ = 0.45, respectively; P < .05). The AUCs for APRI, FIB-4, King's score, and Forns index were 0.77, 0.73, 0.79, and 0.77, respectively, in the diagnosis of substantial fibrosis and 0.70, 0.71, 0.72, and 0.74, respectively, in the diagnosis of cirrhosis. In the validation cohort, AUCs of noninvasive methods used to assess different fibrosis stages did not significantly differ from those for the index cohort. AUCs of 2D SWE in the diagnosis of substantial fibrosis, severe fibrosis, and cirrhosis were 0.97, 0.97, and 0.98, respectively, which were significantly higher than those in serum models (P < .05). Conclusion The 2D SWE protocol could be used to predict substantial fibrosis, severe fibrosis, and cirrhosis in patients with CHB with notably higher diagnostic accuracy than that attained with serum fibrosis models. © RSNA, 2016.
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Affiliation(s)
- Yuan Zhuang
- From the Departments of Ultrasound (Y. Zhuang, H.D., Y. Zhang, W.W.), Surgery (H.S.), and Pathology (C.X.), Zhongshan Hospital, Fudan University, 180 Fenglin Rd, Shanghai 200032, China
| | - Hong Ding
- From the Departments of Ultrasound (Y. Zhuang, H.D., Y. Zhang, W.W.), Surgery (H.S.), and Pathology (C.X.), Zhongshan Hospital, Fudan University, 180 Fenglin Rd, Shanghai 200032, China
| | - Yue Zhang
- From the Departments of Ultrasound (Y. Zhuang, H.D., Y. Zhang, W.W.), Surgery (H.S.), and Pathology (C.X.), Zhongshan Hospital, Fudan University, 180 Fenglin Rd, Shanghai 200032, China
| | - Huichuan Sun
- From the Departments of Ultrasound (Y. Zhuang, H.D., Y. Zhang, W.W.), Surgery (H.S.), and Pathology (C.X.), Zhongshan Hospital, Fudan University, 180 Fenglin Rd, Shanghai 200032, China
| | - Chen Xu
- From the Departments of Ultrasound (Y. Zhuang, H.D., Y. Zhang, W.W.), Surgery (H.S.), and Pathology (C.X.), Zhongshan Hospital, Fudan University, 180 Fenglin Rd, Shanghai 200032, China
| | - Wenping Wang
- From the Departments of Ultrasound (Y. Zhuang, H.D., Y. Zhang, W.W.), Surgery (H.S.), and Pathology (C.X.), Zhongshan Hospital, Fudan University, 180 Fenglin Rd, Shanghai 200032, China
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Dittmann F, Tzschätzsch H, Hirsch S, Barnhill E, Braun J, Sack I, Guo J. Tomoelastography of the abdomen: Tissue mechanical properties of the liver, spleen, kidney, and pancreas from single MR elastography scans at different hydration states. Magn Reson Med 2016; 78:976-983. [DOI: 10.1002/mrm.26484] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/17/2016] [Accepted: 09/07/2016] [Indexed: 12/11/2022]
Affiliation(s)
- Florian Dittmann
- Department of Radiology; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - Heiko Tzschätzsch
- Department of Radiology; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - Sebastian Hirsch
- Department of Radiology; Charité - Universitätsmedizin Berlin; Berlin Germany
| | - Eric Barnhill
- 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
| | - Jing Guo
- Department of Radiology; Charité - Universitätsmedizin Berlin; Berlin Germany
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16
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Test–retest reliability of 3D EPI MR elastography of the pancreas. Clin Radiol 2016; 71:1068.e7-1068.e12. [DOI: 10.1016/j.crad.2016.03.014] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2015] [Revised: 03/05/2016] [Accepted: 03/23/2016] [Indexed: 12/23/2022]
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17
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Chatelin S, Humbert-Claude M, Garteiser P, Ricobaraza A, Vilgrain V, Van Beers BE, Sinkus R, Lenkei Z. Cannabinoid receptor activation in the juvenile rat brain results in rapid biomechanical alterations: Neurovascular mechanism as a putative confounding factor. J Cereb Blood Flow Metab 2016; 36:954-64. [PMID: 26661178 PMCID: PMC4853836 DOI: 10.1177/0271678x15606923] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 08/03/2015] [Indexed: 12/21/2022]
Abstract
We have recently reported cannabinoid-induced rapid changes in the structure of individual neurons. In order to investigate the presence of similar effects at the regional level, measures of brain tissue biomechanics are required. However, cannabinoids are known to alter cerebral blood flow (CBF), putatively resulting in presently unexplored changes in cerebral tissue biomechanics. Here we used magnetic resonance elastography (MRE) and flow-sensitive alternating inversion recovery (FAIR) imaging to measure in vivo alterations of mechanical properties and CBF, respectively, in the rat hippocampus, a brain region with a high density of type-1 cannabinoid receptors (CB1R). Systemic injection of the cannabinoid agonist CP55,940 (0.7 mg/kg) induced a significant stiffness decrease of 10.5 ± 1.2% at 15 minutes. FAIR imaging indicated a comparable decrease (11.3 ± 1.9%) in CBF. Both effects were specific to CB1R activation, as shown by pretreatment with the CB1R-specific antagonist AM251. Strikingly, similar rapid parallel changes of brain elasticity and CBF were also observed after systemic treatment with the hypotensive drug nicardipine. Our results reveal important drug-induced parallel changes in CBF and brain mechanical characteristics, and show that blood flow-dependent tissue softening has to be considered as an important putative confounding factor when cerebral viscoelastic changes are investigated.
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Affiliation(s)
- Simon Chatelin
- Laboratory of Imaging Biomarkers, UMR1149 INSERM-University Paris Diderot, Sorbonne Paris Cité, Paris, France These authors contributed equally to this work
| | - Marie Humbert-Claude
- Brain Plasticity Unit, CNRS UMR8249, ESPCI-ParisTech, PSL Research University, Paris, France These authors contributed equally to this work
| | - Philippe Garteiser
- Laboratory of Imaging Biomarkers, UMR1149 INSERM-University Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Ana Ricobaraza
- Brain Plasticity Unit, CNRS UMR8249, ESPCI-ParisTech, PSL Research University, Paris, France
| | - Valérie Vilgrain
- Laboratory of Imaging Biomarkers, UMR1149 INSERM-University Paris Diderot, Sorbonne Paris Cité, Paris, France Department of Radiology, Assistance-Publique Hôpitaux de Paris, Clichy, France
| | - Bernard E Van Beers
- Laboratory of Imaging Biomarkers, UMR1149 INSERM-University Paris Diderot, Sorbonne Paris Cité, Paris, France Department of Radiology, Assistance-Publique Hôpitaux de Paris, Clichy, France
| | - Ralph Sinkus
- Laboratory of Imaging Biomarkers, UMR1149 INSERM-University Paris Diderot, Sorbonne Paris Cité, Paris, France These authors contributed equally to this work
| | - Zsolt Lenkei
- Brain Plasticity Unit, CNRS UMR8249, ESPCI-ParisTech, PSL Research University, Paris, France These authors contributed equally to this work
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Low G, Kruse SA, Lomas DJ. General review of magnetic resonance elastography. World J Radiol 2016; 8:59-72. [PMID: 26834944 PMCID: PMC4731349 DOI: 10.4329/wjr.v8.i1.59] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 11/14/2015] [Accepted: 12/04/2015] [Indexed: 02/06/2023] Open
Abstract
Magnetic resonance elastography (MRE) is an innovative imaging technique for the non-invasive quantification of the biomechanical properties of soft tissues via the direct visualization of propagating shear waves in vivo using a modified phase-contrast magnetic resonance imaging (MRI) sequence. Fundamentally, MRE employs the same physical property that physicians utilize when performing manual palpation - that healthy and diseased tissues can be differentiated on the basis of widely differing mechanical stiffness. By performing “virtual palpation”, MRE is able to provide information that is beyond the capabilities of conventional morphologic imaging modalities. In an era of increasing adoption of multi-parametric imaging approaches for solving complex problems, MRE can be seamlessly incorporated into a standard MRI examination to provide a rapid, reliable and comprehensive imaging evaluation at a single patient appointment. Originally described by the Mayo Clinic in 1995, the technique represents the most accurate non-invasive method for the detection and staging of liver fibrosis and is currently performed in more than 100 centers worldwide. In this general review, the mechanical properties of soft tissues, principles of MRE, clinical applications of MRE in the liver and beyond, and limitations and future directions of this discipline -are discussed. Selected diagrams and images are provided for illustration.
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Abstract
Noninvasive methods are increasingly used for the assessment of liver fibrosis. Two categories of markers include serum-based markers (biologic properties) or ultrasound and magnetic resonance imaging-based techniques that use the principles of elastography (physical properties) to indirectly assess liver fibrosis. Serum markers can be either direct or indirect markers of the fibrosis process. Common elastography-based studies include vibration-controlled transient elastography, point shear wave elastography, and 2-dimensional shear wave elastography and magnetic resonance elastography. A common theme among all techniques is the inability to accurately differentiate between minimal or moderate stages of fibrosis but superior performance in identifying subjects with cirrhosis or normal liver parenchyma. Noninvasive markers may also serve as prognostic tools to course the natural history of chronic liver disease as well as identify cirrhotic patients at highest risk of future decompensation. Further research is needed to identify the role of noninvasive markers in following asymptomatic individuals, especially in patients with nonalcoholic fatty liver disease.
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Itoh Y, Takehara Y, Kawase T, Terashima K, Ohkawa Y, Hirose Y, Koda A, Hyodo N, Ushio T, Hirai Y, Yoshizawa N, Yamashita S, Nasu H, Ohishi N, Sakahara H. Feasibility of magnetic resonance elastography for the pancreas at 3T. J Magn Reson Imaging 2015; 43:384-90. [DOI: 10.1002/jmri.24995] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 06/18/2015] [Indexed: 01/27/2023] Open
Affiliation(s)
- Yohei Itoh
- Department of Diagnostic Radiology & Nuclear Medicine; Hamamatsu University, School of Medicine; Hamamatsu Japan
| | - Yasuo Takehara
- Department of Radiology; Hamamatsu University Hospital; Hamamatsu Japan
| | - Toshihiro Kawase
- Department of Radiological Technology; Chutoen General Medical Center; Kakegawa Japan
| | | | - Yoshihisa Ohkawa
- Department of Diagnostic Radiology; Chutoen General Medical Center; Kakegawa Japan
| | - Yuko Hirose
- Department of Diagnostic Radiology & Nuclear Medicine; Hamamatsu University, School of Medicine; Hamamatsu Japan
| | - Ai Koda
- Department of Diagnostic Radiology & Nuclear Medicine; Hamamatsu University, School of Medicine; Hamamatsu Japan
| | - Naoko Hyodo
- Department of Diagnostic Radiology & Nuclear Medicine; Hamamatsu University, School of Medicine; Hamamatsu Japan
| | - Takasuke Ushio
- Department of Diagnostic Radiology & Nuclear Medicine; Hamamatsu University, School of Medicine; Hamamatsu Japan
| | - Yuki Hirai
- Department of Diagnostic Radiology & Nuclear Medicine; Hamamatsu University, School of Medicine; Hamamatsu Japan
| | - Nobuko Yoshizawa
- Department of Diagnostic Radiology & Nuclear Medicine; Hamamatsu University, School of Medicine; Hamamatsu Japan
| | - Shuhei Yamashita
- Department of Diagnostic Radiology & Nuclear Medicine; Hamamatsu University, School of Medicine; Hamamatsu Japan
| | - Hatsuko Nasu
- Department of Diagnostic Radiology & Nuclear Medicine; Hamamatsu University, School of Medicine; Hamamatsu Japan
| | - Naoki Ohishi
- Department of Radiology; Hamamatsu University Hospital; Hamamatsu Japan
| | - Harumi Sakahara
- Department of Diagnostic Radiology & Nuclear Medicine; Hamamatsu University, School of Medicine; Hamamatsu Japan
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Tang A, Cloutier G, Szeverenyi NM, Sirlin CB. Ultrasound Elastography and MR Elastography for Assessing Liver Fibrosis: Part 1, Principles and Techniques. AJR Am J Roentgenol 2015; 205:22-32. [PMID: 25905647 PMCID: PMC4819982 DOI: 10.2214/ajr.15.14552] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE The purpose of this article is to provide an overview of ultrasound and MR elastography, including a glossary of relevant terminology, a classification of elastography techniques, and a discussion of their respective strengths and limitations. CONCLUSION Elastography is an emerging technique for the noninvasive assessment of mechanical tissue properties. These techniques report metrics related to tissue stiffness, such as shear-wave speed, magnitude of the complex shear modulus, and the Young modulus.
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Affiliation(s)
- An Tang
- 1 Department of Radiology, Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada
- 2 Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada
- 3 Department of Radiology, Radio-Oncology and Nuclear Medicine, Université de Montréal, Montréal, QC, Canada
| | - Guy Cloutier
- 2 Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada
- 3 Department of Radiology, Radio-Oncology and Nuclear Medicine, Université de Montréal, Montréal, QC, Canada
- 4 Institute of Biomedical Engineering, Université de Montréal, Montréal, QC, Canada
- 5 Laboratory of Biorheology and Medical Ultrasonics, Centre hospitalier de l'Université de Montréal, Montréal, QC, Canada
| | - Nikolaus M Szeverenyi
- 6 Liver Imaging Group, Department of Radiology, University of California San Diego, 408 Dickinson St, San Diego, CA 92103-8226
| | - Claude B Sirlin
- 6 Liver Imaging Group, Department of Radiology, University of California San Diego, 408 Dickinson St, San Diego, CA 92103-8226
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Ultrasound Elastography and MR Elastography for Assessing Liver Fibrosis: Part 2, Diagnostic Performance, Confounders, and Future Directions. AJR Am J Roentgenol 2015; 205:33-40. [PMID: 25905762 DOI: 10.2214/ajr.15.14553] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE The purpose of the article is to review the diagnostic performance of ultra-sound and MR elastography techniques for detection and staging of liver fibrosis, the main current clinical applications of elastography in the abdomen. CONCLUSION Technical and instrument-related factors and biologic and patient-related factors may constitute potential confounders of stiffness measurements for assessment of liver fibrosis. Future developments may expand the scope of elastography for monitoring liver fibrosis and predict complications of chronic liver disease.
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Low G, Owen NE, Joubert I, Patterson AJ, Graves MJ, Alexander GJM, Lomas DJ. Magnetic resonance elastography in the detection of hepatorenal syndrome in patients with cirrhosis and ascites. Eur Radiol 2015; 25:2851-8. [PMID: 25903705 DOI: 10.1007/s00330-015-3723-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 03/18/2015] [Accepted: 03/18/2015] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Hepatorenal syndrome (HRS) is the most lethal cause of renal impairment in cirrhosis. Magnetic resonance elastography (MRE) is a diagnostic test that characterises tissues based on their biomechanical properties. The aim of this study was to assess the feasibility of MRE for detecting HRS in cirrhotic patients. METHODS A prospective diagnostic investigation was performed. Renal MRE was performed on 21 hospitalised patients with cirrhosis and ascites. Six patients had HRS, one patient had non-HRS renal impairment, and 14 patients had normal renal function. The MRE-measured renal stiffness was compared against the clinical diagnosis as determined by clinical review alongside laboratory and radiologic results. RESULTS The MRE-measured renal stiffness was significantly lower in patients with HRS (median stiffness of 3.30 kPa at 90 Hz and 2.62 kPa at 60 Hz) compared with patients with normal renal function (median stiffness of 5.08 kPa at 90 Hz and 3.41 kPa at 60 Hz) (P ≤ 0.014). For the detection of HRS, MRE had an area under the receiver operating characteristic curve of 0.94 at 90 Hz and 0.89 at 60 Hz. MRE had excellent inter-rater agreement, as assessed by Bland-Altman and intraclass correlation coefficient (> 0.9). CONCLUSION MRE shows potential in the detection of HRS. KEY POINTS • Magnetic resonance elastography (MRE) shows promise in the detection of hepatorenal syndrome. • MRE has the potential to track renal disease in a clinical population. • MRE is a reliable diagnostic test with excellent inter-rater agreement.
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Affiliation(s)
- Gavin Low
- Department of Radiology, Addenbrooke's Hospital, Cambridge University Hospitals NHS Foundation Trust Hospital, England, UK,
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Yoon JH, Lee JM, Suh KS, Lee KW, Yi NJ, Lee KB, Han JK, Choi BI. Combined Use of MR Fat Quantification and MR Elastography in Living Liver Donors: Can It Reduce the Need for Preoperative Liver Biopsy? Radiology 2015; 276:453-64. [PMID: 25763828 DOI: 10.1148/radiol.15140908] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE To evaluate the diagnostic performance of magnetic resonance (MR) fat quantification and MR elastography for the assessment of hepatic steatosis and fibrosis in living liver donor candidates. MATERIALS AND METHODS This retrospective study was approved by the institutional review board, and the requirement of informed consent was waived. Donors who underwent MR fat quantification and MR elastography at 1.5 T, followed by liver biopsy, were chronologically grouped into test and validation groups. In the test group (n = 362), MR fat fraction and liver stiffness were compared among donors with normal parenchyma (n = 244), simple steatosis (n = 71), steatosis with inflammatory activity (n = 21), nonalcoholic steatohepatitis (n = 17), and fibrosis (n = 9). Diagnostic performance of the two techniques was assessed by using receiver operating characteristic curve analysis for the detection of substantial steatosis (macrovesicular fat ≥ 10%) or fibrosis (≥F1) and was tested in a validation group (n = 34). RESULTS In the test group, donors with steatosis showed significantly higher fat fraction than donors without steatosis (P < .0001), and donors with fibrosis and nonalcoholic steatohepatitis showed significantly higher liver stiffness values than donors without fibrosis (P < .0001). Areas under the curve were 0.93 (cutoff value > 5.8%) for MR fat quantification and 0.85 (cutoff value > 1.94 kPa) for MR elastography. By using those values, the combination of the two techniques could be used to detect substantial steatosis or fibrosis with 100% sensitivity (12 of 12 patients, 95% confidence interval: 73.4%, 100%) and 100% negative predictive value (15 of 15 patients, 95% confidence interval: 78.0%, 100%) in the validation group. CONCLUSION A combination of MR fat quantification and MR elastography can provide sufficient sensitivity to detect substantial steatosis or fibrosis (≥F1) in liver donor candidates.
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Affiliation(s)
- Jeong Hee Yoon
- From the Departments of Radiology (J.H.Y., J.M.L., J.K.H., B.I.C.), Surgery (K.S.S., K.W.L., N.J.Y.), and Pathology (K.B.L.), Seoul National University Hospital, Seoul, South Korea; and Institute of Radiation Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 110-744, South Korea (J.M.L., J.K.H., B.I.C.)
| | - Jeong Min Lee
- From the Departments of Radiology (J.H.Y., J.M.L., J.K.H., B.I.C.), Surgery (K.S.S., K.W.L., N.J.Y.), and Pathology (K.B.L.), Seoul National University Hospital, Seoul, South Korea; and Institute of Radiation Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 110-744, South Korea (J.M.L., J.K.H., B.I.C.)
| | - Kyung-Suk Suh
- From the Departments of Radiology (J.H.Y., J.M.L., J.K.H., B.I.C.), Surgery (K.S.S., K.W.L., N.J.Y.), and Pathology (K.B.L.), Seoul National University Hospital, Seoul, South Korea; and Institute of Radiation Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 110-744, South Korea (J.M.L., J.K.H., B.I.C.)
| | - Kwan-Woong Lee
- From the Departments of Radiology (J.H.Y., J.M.L., J.K.H., B.I.C.), Surgery (K.S.S., K.W.L., N.J.Y.), and Pathology (K.B.L.), Seoul National University Hospital, Seoul, South Korea; and Institute of Radiation Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 110-744, South Korea (J.M.L., J.K.H., B.I.C.)
| | - Nam-Joon Yi
- From the Departments of Radiology (J.H.Y., J.M.L., J.K.H., B.I.C.), Surgery (K.S.S., K.W.L., N.J.Y.), and Pathology (K.B.L.), Seoul National University Hospital, Seoul, South Korea; and Institute of Radiation Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 110-744, South Korea (J.M.L., J.K.H., B.I.C.)
| | - Kyung Bun Lee
- From the Departments of Radiology (J.H.Y., J.M.L., J.K.H., B.I.C.), Surgery (K.S.S., K.W.L., N.J.Y.), and Pathology (K.B.L.), Seoul National University Hospital, Seoul, South Korea; and Institute of Radiation Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 110-744, South Korea (J.M.L., J.K.H., B.I.C.)
| | - Joon Koo Han
- From the Departments of Radiology (J.H.Y., J.M.L., J.K.H., B.I.C.), Surgery (K.S.S., K.W.L., N.J.Y.), and Pathology (K.B.L.), Seoul National University Hospital, Seoul, South Korea; and Institute of Radiation Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 110-744, South Korea (J.M.L., J.K.H., B.I.C.)
| | - Byung Ihn Choi
- From the Departments of Radiology (J.H.Y., J.M.L., J.K.H., B.I.C.), Surgery (K.S.S., K.W.L., N.J.Y.), and Pathology (K.B.L.), Seoul National University Hospital, Seoul, South Korea; and Institute of Radiation Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 110-744, South Korea (J.M.L., J.K.H., B.I.C.)
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Shi Y, Glaser KJ, Sudhakar VK, Ben-Abraham EI, Ehman RL. Feasibility of using 3D MR elastography to determine pancreatic stiffness in healthy volunteers. J Magn Reson Imaging 2015; 41:369-75. [PMID: 24497052 PMCID: PMC4122650 DOI: 10.1002/jmri.24572] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 01/02/2014] [Indexed: 01/02/2023] Open
Abstract
PURPOSE To evaluate the feasibility of using three-dimensional (3D) MR elastography (MRE) to determine the stiffness of the pancreas in healthy volunteers. MATERIALS AND METHODS Twenty healthy volunteers underwent 1.5 Tesla MRE exams using an accelerated echo planar imaging (EPI) pulse sequence with low-frequency vibrations (40 and 60 Hz). Stiffness was calculated with a 3D direct inversion algorithm. The mean shear stiffness in five pancreatic subregions (uncinate, head, neck, body, and tail) and the corresponding liver stiffness were calculated. The intrasubject coefficient of variation (CV) was calculated as a measure of the reproducibility for each volunteer. RESULTS The mean shear stiffness (average of values obtained in different pancreatic subregions) was (1.15 ± 0.17) kPa at 40 Hz, and (2.09 ± 0.33) kPa at 60 Hz. The corresponding liver stiffness was higher than the pancreas stiffness at 40 Hz ([1.60 ± 0.21] kPa, mean pancreas-to-liver stiffness ratio: 0.72), but similar at 60Hz ([2.12 ± 0.23) kPa, mean ratio: 0.95). The mean intrasubject CV for each pancreatic subregion was lower at 40 Hz than 60 Hz (P < 0.05 for all subregions, range: 11.9-15.7% at 40 Hz and 16.5-19.6% at 60 Hz). CONCLUSION The 3D pancreatic MRE can provide promising and reproducible stiffness measurements throughout the pancreas, with more consistent data acquired at 40 Hz.
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Affiliation(s)
- Yu Shi
- Department of Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905
- Department of Radiology, Shengjing Hospital, China Medical University, No.36, Sanhao Street, Heping District, Shenyang, 110004, P.R. China
| | - Kevin J. Glaser
- Department of Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905
| | | | | | - Richard L. Ehman
- Department of Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905
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Edelman RR. The history of MR imaging as seen through the pages of radiology. Radiology 2015; 273:S181-200. [PMID: 25340436 DOI: 10.1148/radiol.14140706] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The first reports in Radiology pertaining to magnetic resonance (MR) imaging were published in 1980, 7 years after Paul Lauterbur pioneered the first MR images and 9 years after the first human computed tomographic images were obtained. Historical advances in the research and clinical applications of MR imaging very much parallel the remarkable advances in MR imaging technology. These advances can be roughly classified into hardware (eg, magnets, gradients, radiofrequency [RF] coils, RF transmitter and receiver, MR imaging-compatible biopsy devices) and imaging techniques (eg, pulse sequences, parallel imaging, and so forth). Image quality has been dramatically improved with the introduction of high-field-strength superconducting magnets, digital RF systems, and phased-array coils. Hybrid systems, such as MR/positron emission tomography (PET), combine the superb anatomic and functional imaging capabilities of MR imaging with the unsurpassed capability of PET to demonstrate tissue metabolism. Supported by the improvements in hardware, advances in pulse sequence design and image reconstruction techniques have spurred dramatic improvements in imaging speed and the capability for studying tissue function. In this historical review, the history of MR imaging technology and developing research and clinical applications, as seen through the pages of Radiology, will be considered.
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Affiliation(s)
- Robert R Edelman
- From the Department of Radiology, NorthShore University HealthSystem, 2650 Ridge Ave, Evanston, IL 60201
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Yoon JH, Lee JM, Joo I, Lee ES, Sohn JY, Jang SK, Lee KB, Han JK, Choi BI. Hepatic Fibrosis: Prospective Comparison of MR Elastography and US Shear-Wave Elastography for Evaluation. Radiology 2014; 273:772-82. [DOI: 10.1148/radiol.14132000] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Wex C, Fröhlich M, Brandstädter K, Bruns C, Stoll A. Experimental analysis of the mechanical behavior of the viscoelastic porcine pancreas and preliminary case study on the human pancreas. J Mech Behav Biomed Mater 2014; 41:199-207. [PMID: 25460416 DOI: 10.1016/j.jmbbm.2014.10.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 10/20/2014] [Accepted: 10/21/2014] [Indexed: 02/06/2023]
Abstract
The aim of this article is to study the mechanical properties of the pancreas. Up to now, the mechanical properties of the pancreas are not sufficiently characterized. The possibility of intraoperative mechanical testing of pathological pancreata will allow the classification of pancreatic diseases in the future. The application of mechanical parameters instead of the intraoperative frozen section analysis shortens waiting times in the operating room. This study proves the general applicability of shear rheology for the determination of the mechanical properties of pancreas and the assessment of graft quality for transplantation. Porcine and human pancreas samples were examined ex vivo and a nonlinear viscoelastic behavior was observed. Pancreas was found to be more viscous than liver but both abdominal organs showed a similar flow behavior. The shear deformation dependence of healthy human pancreas was similar to porcine pancreas. An increase in the post-mortem time led to an increase in the complex modulus for a post-mortem time up to 8.5 days. Histological investigations showed that an increased amount of collagen coincides with the stiffening of the pancreatic tissue.
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Affiliation(s)
- C Wex
- Clinic for General, Visceral and Vascular Surgery, University Clinic Magdeburg, Germany
| | - M Fröhlich
- Clinic for General, Visceral and Vascular Surgery, University Clinic Magdeburg, Germany
| | - K Brandstädter
- Center for Pathology and Forensic Medicine, University Clinic Magdeburg, Germany
| | - C Bruns
- Clinic for General, Visceral and Vascular Surgery, University Clinic Magdeburg, Germany
| | - A Stoll
- Clinic for General, Visceral and Vascular Surgery, University Clinic Magdeburg, Germany.
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Pancreatic fatty degeneration and fibrosis as predisposing factors for the development of pancreatic ductal adenocarcinoma. Pancreas 2014; 43:1032-41. [PMID: 24991971 DOI: 10.1097/mpa.0000000000000159] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVES Knowledge of risk factors for development of pancreatic ductal adenocarcinoma (PDAC) is limited. To clarify the background condition of the pancreas for the development of PDAC, we analyzed pancreatic histological changes in noncancerous lesion specimens after pancreatectomy in PDAC patients. METHODS Seventy-six patients with PDAC were enrolled in this study. The PDAC was in the pancreatic head in 37 patients, in the body in 31, and in the tail in 8. No patients had a history of clinical chronic pancreatitis. As controls, 98 patients without PDAC were enrolled. The following parameters were examined: fibrosis, fatty degeneration, and inflammatory cell infiltration. More than 5% of fatty degeneration in the specimen, more than 10% of fibrosis, and more than 5% of inflammatory cell infiltration were considered positive changes. RESULTS Pancreatectomy specimens showed a higher ratio of positive change in fibrosis (86% vs 42%), fatty degeneration (72% vs 44%), and inflammatory cell infiltration (14% vs 3%) than control samples. Multivariate analyses demonstrated that each histological change was a significant, independent determinant for PDAC. CONCLUSIONS Our study demonstrated that cryptogenic pancreatic inflammation with fatty changes represents an important predisposing factor for PDAC. Screening for subclinical chronic pancreatitis in healthy populations may enable the detection of PDAC at an early stage.
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Takayama Y, Nishie A, Asayama Y, Ushijima Y, Okamoto D, Fujita N, Morita K, Shirabe K, Kotoh K, Kubo Y, Okuaki T, Honda H. T1ρ Relaxation of the liver: A potential biomarker of liver function. J Magn Reson Imaging 2014; 42:188-95. [DOI: 10.1002/jmri.24739] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 08/12/2014] [Indexed: 01/20/2023] Open
Affiliation(s)
- Yukihisa Takayama
- Department of Radiology Informatics and Network; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Akihiro Nishie
- Department of Clinical Radiology; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Yoshiki Asayama
- Department of Clinical Radiology; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Yasuhiro Ushijima
- Department of Clinical Radiology; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Daisuke Okamoto
- Department of Clinical Radiology; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Nobuhiro Fujita
- Department of Clinical Radiology; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Koichiro Morita
- Department of Clinical Radiology; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Ken Shirabe
- Department of Surgery and Science; Graduate School of Medical Sciences, Kyushu University; 3-1-1 Fukuoka Japan
| | - Kazuhiro Kotoh
- Department of Medicine and Bioregulatory Science; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | - Yuichiro Kubo
- Department of Anatomic Pathology, Pathological Sciences; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
| | | | - Hiroshi Honda
- Department of Clinical Radiology; Graduate School of Medical Sciences, Kyushu University; Fukuoka Japan
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Abstract
Magnetic resonance elastography (MRE) assesses tissue stiffness in vivo by imaging propagating shear waves through the tissues and processing the wave information. MRE is a robust technology with excellent technical success; is applicable in almost all patients and body habitus; and has excellent reproducibility, repeatability, and interobserver agreement for assessing liver stiffness. It is currently the most accurate noninvasive technique for detection and staging of liver fibrosis and has the potential to replace liver biopsy. This article describes the principles and technique of MRE, current clinical applications, and emerging clinical indications.
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Affiliation(s)
- Sudhakar Kundapur Venkatesh
- Department of Radiology, Mayo Clinic College of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
| | - Richard L Ehman
- Department of Radiology, Mayo Clinic College of Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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Shi Y, Guo Q, Xia F, Dzyubak B, Glaser KJ, Li Q, Li J, Ehman RL. MR elastography for the assessment of hepatic fibrosis in patients with chronic hepatitis B infection: does histologic necroinflammation influence the measurement of hepatic stiffness? Radiology 2014; 273:88-98. [PMID: 24893048 DOI: 10.1148/radiol.14132592] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE To determine the diagnostic performance of magnetic resonance (MR) elastography for the staging of hepatic fibrosis and to evaluate the influence of necroinflammation on hepatic stiffness in patients with chronic hepatitis B virus (HBV) infection by using histopathologic findings as the reference standard. MATERIALS AND METHODS One hundred thirteen consecutive patients with chronic HBV infection were recruited prospectively in this institutional review board-approved study after providing written informed consent between March 2012 and October 2013. The stiffness measurements were obtained by using two-dimensional gradient-echo MR elastography with a 3.0-T MR system. The METAVIR scoring system was used for the assessment of fibrosis ("F" stage) and necroinflammation ("A" grade). The predictive ability of MR elastography was evaluated by using the receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC). Multiple linear regression analyses were conducted to determine the relationship between hepatic stiffness and the variables that showed a significant association in the univariate analysis or those that were of interest for comparison with earlier work (histologic scores, sex, age, aspartate aminotransferase level, and aspartate aminotransferase/alanine aminotransferase ratio). RESULTS MR elastography showed excellent performance for characterization of ≥ F1, ≥ F2, ≥ F3, and F4 findings, with AUC values of 0.961, 0.986, 1.000, and 0.998, respectively. It showed a moderate capability for evaluation of necroinflammatory activity of ≥ A1, ≥ A2, and A3 (AUC = 0.806, 0.834, and 0.906, respectively). Multiple linear regression analysis showed that fibrosis, necroinflammation, and sex were independently associated with hepatic stiffness (β = 0.799, 0.277, and 0.070, respectively; P < .05). For pairwise comparisons, log-transformed hepatic stiffness showed no difference between (a) groups F0/A2-3 and F1/A0-1 and (b) groups F1/A2-3 and F2/A0-1 (P > .99 and P = .486, respectively). CONCLUSION MR elastography demonstrated excellent performance for distinguishing the stages of hepatic fibrosis in patients with chronic HBV infection. For hepatic tissue with ≤ F2 fibrosis, necroinflammation can account for a substantial fraction of the increase in hepatic stiffness.
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Affiliation(s)
- Yu Shi
- From the Departments of Radiology (Y.S., Q.G., Q.L., J.L.) and Infectious Disease (F.X.), Shengjing Hospital, China Medical University, 36 Sanhao St, Heping District, Shenyang 110004, People's Republic of China; and Departments of Biomedical Engineering (B.D.) and Radiology (K.J.G., R.L.E.), Mayo Clinic, Rochester, Minn
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Shi Y, Guo Q, Xia F, Dzyubak B, Glaser KJ, Li Q, Li J, Ehman RL. MR elastography for the assessment of hepatic fibrosis in patients with chronic hepatitis B infection: does histologic necroinflammation influence the measurement of hepatic stiffness? Radiology 2014. [PMID: 24893048 DOI: 10.1148/radiol.14132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE To determine the diagnostic performance of magnetic resonance (MR) elastography for the staging of hepatic fibrosis and to evaluate the influence of necroinflammation on hepatic stiffness in patients with chronic hepatitis B virus (HBV) infection by using histopathologic findings as the reference standard. MATERIALS AND METHODS One hundred thirteen consecutive patients with chronic HBV infection were recruited prospectively in this institutional review board-approved study after providing written informed consent between March 2012 and October 2013. The stiffness measurements were obtained by using two-dimensional gradient-echo MR elastography with a 3.0-T MR system. The METAVIR scoring system was used for the assessment of fibrosis ("F" stage) and necroinflammation ("A" grade). The predictive ability of MR elastography was evaluated by using the receiver operating characteristic (ROC) curve and the area under the ROC curve (AUC). Multiple linear regression analyses were conducted to determine the relationship between hepatic stiffness and the variables that showed a significant association in the univariate analysis or those that were of interest for comparison with earlier work (histologic scores, sex, age, aspartate aminotransferase level, and aspartate aminotransferase/alanine aminotransferase ratio). RESULTS MR elastography showed excellent performance for characterization of ≥ F1, ≥ F2, ≥ F3, and F4 findings, with AUC values of 0.961, 0.986, 1.000, and 0.998, respectively. It showed a moderate capability for evaluation of necroinflammatory activity of ≥ A1, ≥ A2, and A3 (AUC = 0.806, 0.834, and 0.906, respectively). Multiple linear regression analysis showed that fibrosis, necroinflammation, and sex were independently associated with hepatic stiffness (β = 0.799, 0.277, and 0.070, respectively; P < .05). For pairwise comparisons, log-transformed hepatic stiffness showed no difference between (a) groups F0/A2-3 and F1/A0-1 and (b) groups F1/A2-3 and F2/A0-1 (P > .99 and P = .486, respectively). CONCLUSION MR elastography demonstrated excellent performance for distinguishing the stages of hepatic fibrosis in patients with chronic HBV infection. For hepatic tissue with ≤ F2 fibrosis, necroinflammation can account for a substantial fraction of the increase in hepatic stiffness.
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Affiliation(s)
- Yu Shi
- From the Departments of Radiology (Y.S., Q.G., Q.L., J.L.) and Infectious Disease (F.X.), Shengjing Hospital, China Medical University, 36 Sanhao St, Heping District, Shenyang 110004, People's Republic of China; and Departments of Biomedical Engineering (B.D.) and Radiology (K.J.G., R.L.E.), Mayo Clinic, Rochester, Minn
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Pang JXQ, Zimmer S, Niu S, Crotty P, Tracey J, Pradhan F, Shaheen AAM, Coffin CS, Heitman SJ, Kaplan GG, Swain MG, Myers RP. Liver stiffness by transient elastography predicts liver-related complications and mortality in patients with chronic liver disease. PLoS One 2014; 9:e95776. [PMID: 24755824 PMCID: PMC3995722 DOI: 10.1371/journal.pone.0095776] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 03/29/2014] [Indexed: 12/18/2022] Open
Abstract
Background Liver stiffness measurement (LSM) by transient elastography (TE, FibroScan) is a validated method for noninvasively staging liver fibrosis. Most hepatic complications occur in patients with advanced fibrosis. Our objective was to determine the ability of LSM by TE to predict hepatic complications and mortality in a large cohort of patients with chronic liver disease. Methods In consecutive adults who underwent LSM by TE between July 2008 and June 2011, we used Cox regression to determine the independent association between liver stiffness and death or hepatic complications (decompensation, hepatocellular carcinoma, and liver transplantation). The performance of LSM to predict complications was determined using the c-statistic. Results Among 2,052 patients (median age 51 years, 65% with hepatitis B or C), 87 patients (4.2%) died or developed a hepatic complication during a median follow-up period of 15.6 months (interquartile range, 11.0–23.5 months). Patients with complications had higher median liver stiffness than those without complications (13.5 vs. 6.0 kPa; P<0.00005). The 2-year incidence rates of death or hepatic complications were 2.6%, 9%, 19%, and 34% in patients with liver stiffness <10, 10–19.9, 20–39.9, and ≥40 kPa, respectively (P<0.00005). After adjustment for potential confounders, liver stiffness by TE was an independent predictor of complications (hazard ratio [HR] 1.05 per kPa; 95% confidence interval [CI] 1.03–1.06). The c-statistic of liver-stiffness for predicting complications was 0.80 (95% CI 0.75–0.85). A liver stiffness below 20 kPa effectively excluded complications (specificity 93%, negative predictive value 97%); however, the positive predictive value of higher results was sub-optimal (20%). Conclusions Liver stiffness by TE accurately predicts the risk of death or hepatic complications in patients with chronic liver disease. TE may facilitate the estimation of prognosis and guide management of these patients.
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Affiliation(s)
- Jack X. Q. Pang
- Liver Unit, Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Scott Zimmer
- Medical Services, Alberta Health Services, Calgary, Alberta, Canada
| | - Sophia Niu
- Medical Services, Alberta Health Services, Calgary, Alberta, Canada
| | - Pam Crotty
- Liver Unit, Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jenna Tracey
- Liver Unit, Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Faruq Pradhan
- Liver Unit, Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Abdel Aziz M. Shaheen
- Liver Unit, Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Carla S. Coffin
- Liver Unit, Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Steven J. Heitman
- Liver Unit, Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Gilaad G. Kaplan
- Liver Unit, Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Mark G. Swain
- Liver Unit, Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Robert P. Myers
- Liver Unit, Division of Gastroenterology and Hepatology, Department of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Community Health Sciences, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
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Zardi EM, Di Matteo FM, Pacella CM, Sanyal AJ. Invasive and non-invasive techniques for detecting portal hypertension and predicting variceal bleeding in cirrhosis: a review. Ann Med 2014; 46:8-17. [PMID: 24328372 PMCID: PMC4904298 DOI: 10.3109/07853890.2013.857831] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Portal hypertension is a severe syndrome that may derive from pre-sinusoidal, sinusoidal, and post-sinusoidal causes. As a consequence, several complications (i.e. ascites, oesophageal varices) may develop. In sinusoidal portal hypertension, hepatic venous pressure gradient (HVPG) is a reliable method for defining the grade of portal pressure, establishing the effectiveness of the treatment, and predicting the occurrence of complications; however, some questions exist regarding its ability to discriminate bleeding from non-bleeding varices in cirrhotic patients. Other imaging techniques (transient elastography, endoscopy, endosonography, and duplex Doppler sonography) for assessing causes and complications of portal hypertensive syndrome are available and may be valuable for the management of these patients. In this review, we evaluate invasive and non-invasive techniques currently employed to obtain a clinical prediction of deadly complications, such as variceal bleeding in patients affected by sinusoidal portal hypertension, in order to create a diagnostic algorithm to manage them. Again, HVPG appears to be the reference standard to evaluate portal hypertension and monitor the response to treatment, but its ability to predict several complications and support management decisions might be further improved through the diagnostic combination with other imaging techniques.
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Affiliation(s)
- Enrico Maria Zardi
- Department of Clinical Medicine, 'Campus Bio-Medico' University , Rome , Italy
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Non-invasive evaluation of liver fibrosis: a comparison of ultrasound-based transient elastography and MR elastography in patients with viral hepatitis B and C. Eur Radiol 2013; 24:638-48. [DOI: 10.1007/s00330-013-3046-0] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 09/26/2013] [Accepted: 10/02/2013] [Indexed: 12/20/2022]
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Serai SD, Wallihan DB, Venkatesh SK, Ehman RL, Campbell KM, Sticka J, Marino BS, Podberesky DJ. Magnetic resonance elastography of the liver in patients status-post fontan procedure: feasibility and preliminary results. CONGENIT HEART DIS 2013; 9:7-14. [PMID: 24134059 DOI: 10.1111/chd.12144] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/07/2013] [Indexed: 01/06/2023]
Abstract
OBJECTIVE The purpose of this study was to evaluate the feasibility of performing magnetic resonance elastography (MRE) as a screening tool for elevated liver stiffness in patients' status-post Fontan procedure. BACKGROUND With greater numbers of Fontan patients surviving far into adulthood, a factor increasingly affecting long-term prognosis is the presence of hepatic congestion and fibrosis. If detected early, steps can be taken to potentially slow or halt the progression of fibrosis. MRE is a relatively new, noninvasive imaging technique, which can quantitatively measure liver stiffness and provide an estimate of the extent of fibrosis. METHODS A retrospective study was conducted using MRE to evaluate liver stiffness in patients with a history of Fontan procedure. An MRE was performed in the same session as a clinical cardiac MRI. The liver was interrogated at four slice locations, and a mean liver stiffness value was calculated for each patient using postprocessing software. The medical records were reviewed for demographic and clinical characteristics. RESULTS During the time frame of this investigation, 17 MRE exams were performed on 16 patients. All patients had elevated liver stiffness values as defined by MRE standards. The median of the individual mean liver stiffness values was 5.1 kPa (range: 3.4-8.2 kPa). This range of liver stiffness elevation would suggest the presence of mild to severe fibrosis in a patient with standard cardiovascular anatomy. We found a significant trend toward higher liver stiffness values with greater duration of Fontan circulation (rs = 0.55, P = .02). CONCLUSION Our preliminary findings suggest that MRE is a feasible method for evaluating the liver in Fontan patients who are undergoing surveillance cardiac MRI. Further investigation with histologic correlation is needed to determine the contributions of hepatic congestion and fibrosis to the liver stiffness in this population.
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Affiliation(s)
- Suraj D Serai
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
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Yin M, Kolipaka A, Woodrum DA, Glaser KJ, Romano AJ, Manduca A, Talwalkar JA, Araoz PA, McGee KP, Anavekar NS, Ehman RL. Hepatic and splenic stiffness augmentation assessed with MR elastography in an in vivo porcine portal hypertension model. J Magn Reson Imaging 2013; 38:809-15. [PMID: 23418135 PMCID: PMC3661694 DOI: 10.1002/jmri.24049] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Accepted: 12/19/2012] [Indexed: 12/18/2022] Open
Abstract
PURPOSE To investigate the influence of portal pressure on the shear stiffness of the liver and spleen in a well-controlled in vivo porcine model with magnetic resonance elastography (MRE). A significant correlation between portal pressure and tissue stiffness could be used to noninvasively assess increased portal venous pressure (portal hypertension), which is a frequent clinical condition caused by cirrhosis of the liver and is responsible for the development of many lethal complications. MATERIALS AND METHODS During multiple intraarterial infusions of Dextran-40 in three adult domestic pigs in vivo, 3D abdominal MRE was performed with left ventricle and portal catheters measuring blood pressure simultaneously. Least-squares linear regressions were used to analyze the relationship between tissue stiffness and portal pressure. RESULTS Liver and spleen stiffness have a dynamic component that increases significantly following an increase in portal or left ventricular pressure. Correlation coefficients with the linear regressions between stiffness and pressure exceeded 0.8 in most cases. CONCLUSION The observed stiffness-pressure relationship of the liver and spleen could provide a promising noninvasive method for assessing portal pressure. Using MRE to study the tissue mechanics associated with portal pressure may provide new insights into the natural history and pathophysiology of hepatic diseases and may have significant diagnostic value in the future.
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Affiliation(s)
- Meng Yin
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | | | | | | | - Anthony J Romano
- Acoustic Division, Naval Research Laboratory, Washington, DC, USA
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Urban MW, Nenadic IZ, Chen S, Greenleaf JF. Discrepancies in reporting tissue material properties. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2013; 32:886-8. [PMID: 23620333 PMCID: PMC3677533 DOI: 10.7863/ultra.32.5.886] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
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Korsmo MJ, Ebrahimi B, Eirin A, Woollard JR, Krier JD, Crane JA, Warner L, Glaser K, Grimm R, Ehman RL, Lerman LO. Magnetic resonance elastography noninvasively detects in vivo renal medullary fibrosis secondary to swine renal artery stenosis. Invest Radiol 2013; 48:61-8. [PMID: 23262789 PMCID: PMC3694773 DOI: 10.1097/rli.0b013e31827a4990] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Magnetic resonance elastography (MRE) can noninvasively sample tissue stiffness in vivo. Renal fibrosis secondary to renal artery stenosis (RAS), which is aggravated in atherosclerotic RAS (ARAS), may increase its stiffness. An increase in cortical stiffness in vivo can be masked by intrinsic hemodynamic determinants, whereas renal medullary stiffness is less dependent on renal hemodynamics. Therefore, this study tested the hypothesis that MRE-determined medullary stiffness would correspond to the histological degree of medullary fibrosis in stenotic kidneys in RAS and detect its exacerbation in ARAS. MATERIALS AND METHODS Seventeen pigs were studied 10 weeks after induction of unilateral RAS (n = 6), ARAS (n = 5), or sham (n = 6). Stiffness of the cortex and the medulla was determined through 3-dimensional MRE, and renal perfusion and function were determined using multidetector computed tomography. Kidney fibrosis was subsequently assessed ex vivo using the Masson trichrome staining. RESULTS Renal stenotic cortex and medulla were significantly more fibrotic in RAS and ARAS compared with healthy kidney. However, MRE detected increased stiffness in RAS compared with the healthy kidney (12.7 ± 0.41 kPa vs 10.7 ± 0.18 kPa; P = 0.004) only in the medulla, which was further increased in ARAS (16.6 ± 1.3 kPa; P = 0.017 vs RAS). Magnetic resonance elastography-derived medullary, but not cortical, stiffness significantly correlated with histological degree of fibrosis, although cortical and medullary fibroses were correlated. Renal blood flow and function were similarly decreased in RAS and ARAS compared with the healthy kidney. CONCLUSIONS Noninvasive 3-dimensional MRE detects increased renal medullary stiffness in RAS and ARAS in vivo, which correlates with its fibrosis ex vivo and may also reflect cortical fibrosis. Hence, MRE-derived medullary stiffness can be potentially useful in detecting renal fibrosis and track disease progression.
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Affiliation(s)
- Michael J Korsmo
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
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Berzigotti A, Seijo S, Reverter E, Bosch J. Assessing portal hypertension in liver diseases. Expert Rev Gastroenterol Hepatol 2013; 7:141-55. [PMID: 23363263 DOI: 10.1586/egh.12.83] [Citation(s) in RCA: 172] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Portal hypertension is a common complication of chronic liver diseases and is responsible for most clinical consequences of cirrhosis, which represent the more frequent causes of death and liver transplantation in these patients. This review is aimed at clarifying the state-of-the art assessment of portal hypertension and at discussing recent developments in this field. Particular attention is paid to new noninvasive techniques that will be soon available for potential routine use.
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Affiliation(s)
- Annalisa Berzigotti
- Hepatic Hemodynamic Laboratory, Liver Unit, Hospital Clinic - Institut d'Investigacions Biomediques August Pi i Sunyer IDIBAPS, University of Barcelona, Spain
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Amador C, Urban M, Kinnick R, Chen S, Greenleaf JF. In vivo swine kidney viscoelasticity during acute gradual decrease in renal blood flow: pilot study. REVISTA INGENIERIA BIOMEDICA 2013; 7:68-78. [PMID: 24533039 PMCID: PMC3922126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Elasticity imaging methods have been used to study kidney mechanical properties and have demonstrated that the kidney elastic modulus increases with disease state. However, studies in swine suggests that kidney elastic modulus is also affected by hemodynamic variables. A newly emerging method called Shearwave Dispersion Ultrasound Vibrometry (SDUV) offers a tool to determine renal elasticity and viscosity in vivo. The purpose of this study is directed toward evaluating the feasibility of SDUV for in vivo measurements of healthy swine kidney during acute gradual decease of renal blood flow. In this study in vivo SDUV measurements were made on a group of 5 normal swine kidneys at baseline renal blood flow (RBF) and 25, 50, 75 and 100% decrease in RBF. The shear elastic modulus at full baseline was 7.04 ± 0.92 kPa and 3.48 ± 0.20 kPa at 100% decrease in RBF. The viscosity did not change between baseline (2.23 ± 0.33 Pa·s) and 100% decrease in RBF (2.03 ± 0.32 Pa·s). The data from this study indicates that other variables such as local blood flow, pressure and volume as well as method accuracy need to be measured to illustrate the relationship between shear elasticity and viscosity associated with acute kidney processes.
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Affiliation(s)
- Carolina Amador
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, United States, Ultrasound Research Laboratory
| | - Matthew Urban
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, United States, Ultrasound Research Laboratory
| | - Randall Kinnick
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, United States, Ultrasound Research Laboratory
| | - Shigao Chen
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, United States, Ultrasound Research Laboratory
| | - James F Greenleaf
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, United States, Ultrasound Research Laboratory
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Chen SH, Li YF, Lai HC, Kao JT, Peng CY, Chuang PH, Su WP, Chiang IP. Effects of patient factors on noninvasive liver stiffness measurement using acoustic radiation force impulse elastography in patients with chronic hepatitis C. BMC Gastroenterol 2012; 12:105. [PMID: 22877310 PMCID: PMC3462151 DOI: 10.1186/1471-230x-12-105] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 08/02/2012] [Indexed: 02/08/2023] Open
Abstract
Background Previous research has shown variation in the effects of patient factors, including hepatic necroinflammatory activity, on liver stiffness measurement (LSM). This prospective study attempts to identify explanatory factors for LSM in patients with chronic hepatitis C (CHC) using acoustic radiation force impulse (ARFI) technology. Methods A cohort of 127 Taiwanese patients with CHC underwent ARFI LSM and immediate percutaneous liver biopsy. This study compares the concurrent diagnostic performances of LSM and FibroTest using receiver operating characteristic (ROC) curves. Three multiple linear regression models were used to evaluate the significance of concurrent patient factors in explaining LSM. Results To classify METAVIR fibrosis (F) stages, the areas under ROC curves (AUCs) were ARFI LSM, 0.847 (95% confidence interval (CI), 0.779-0.914) and FibroTest, 0.823 (95% CI, 0.748-0.898), for F1 versus F2-4; ARFI LSM, 0.902 (95% CI, 0.835-0.970) and FibroTest, 0.812 (95% CI, 0.735-0.888), for F1-2 versus F3-4; ARFI LSM, 0.831 (95% CI, 0.723-0.939) and FibroTest, 0.757 (95% CI, 0.648-0.865), for F1-3 versus F4. After adjusting for other demographic and biological covariates, biochemical and histological necroinflammatory factors consistently explained LSM. Factors included serum alanine aminotransferase (ALT)/upper limit of normal (ULN) categories (model R2 = 0.661, adjusted R2 = 0.629), ActiTest A scores (R2 = 0.662, adjusted R2 = 0.636), and METAVIR activity (A) grades (R2 = 0.651, adjusted R2 = 0.620). METAVIR F stages, body mass index, and platelet count were also independently associated with LSM. Necroinflammatory degrees, including ALT/ULN, ActiTest A scores, and METAVIR A grades, explained the false positivity of liver fibrosis staging using ARFI LSM. Conclusions The degree of hepatic necroinflammatory activity independently and significantly exaggerated liver fibrosis evaluation using ARFI LSM. However, comparisons with concurrent FibroTest indicate that ARFI LSM may be a promising alternative, or adjunctive single indicator, for liver fibrosis evaluation in patients with CHC.
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Affiliation(s)
- Sheng-Hung Chen
- Division of Hepatogastroenterology, Department of Internal Medicine, China Medical University Hospital, No 2 Yuh-Der Road, Taichung 40402, Taiwan
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Bosch J, Abraldes JG, Albillos A, Aracil C, Bañares R, Berzigotti A, Calleja JL, de la Peña J, Escorsell A, García-Pagán JC, Genescà J, Hernández-Guerra M, Ripoll C, Planas R, Villanueva C. Hipertensión portal: recomendaciones para su evaluación y tratamiento. GASTROENTEROLOGIA Y HEPATOLOGIA 2012; 35:421-50. [DOI: 10.1016/j.gastrohep.2012.02.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 02/15/2012] [Indexed: 12/16/2022]
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Martin DR, Lauenstein T, Kalb B, Lurie C, Kitajima H, Sharma P, Salman K, Moreira R, Farris AB, Spivey J, Martinez E, Hanish S, Adsay V. Liver MRI and histological correlates in chronic liver disease on multiphase gadolinium-enhanced 3D gradient echo imaging. J Magn Reson Imaging 2012; 36:422-9. [PMID: 22566123 DOI: 10.1002/jmri.23668] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 03/12/2012] [Indexed: 12/24/2022] Open
Abstract
PURPOSE To evaluate intrinsic hepatic enhancement patterns on multiphase, gadolinium-enhanced, fat-suppressed, 3D T1-weighted, gradient echo magnetic resonance imaging (MRI) as a quantitative correlate for severity of pathological changes in chronic liver disease (CLD). MATERIALS AND METHODS This study was HIPAA-compliant and Institutional Review Board-approved. In all, 75 patients were studied by contrast-enhanced multiphase abdominal MRI. CLD patients had liver histology correlation derived from right lobe liver biopsies. Contrast-enhanced arterial- and delayed-phase 3D gradient recalled echo (GRE) liver MRI were scored using feature categorization templates to quantify enhancement patterns by three independent readers. Liver histopathology was staged/graded for fibrosis/inflammation using the Scheuer system. Statistical testing for MRI histology correlates used a Pearson's product moment correlation and a Wilcoxon-Mann-Whitney two-sample rank-sum test. Reader agreement was analyzed by a modified Fleiss' kappa test. RESULTS MRI histology correlation was high for delayed-phase MRI versus fibrosis stage (95% confidence interval [CI] 0.941 < r < 0.976, P = 5 × 10(-7)), but lower for all other comparisons (delayed-phase vs. inflammation and arterial-phase vs. inflammation or fibrosis all showed a CI no greater than 0.64). Paired testing between delayed-phase MRI score and histology fibrosis staging incremental levels was significant (from P < 10(-2) to P < 10(-5)). CONCLUSION A standard gadolinium-enhanced liver MRI may provide a correlate measure of hepatic fibrosis over a spectrum of severity.
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Affiliation(s)
- Diego R Martin
- Department of Radiology, University of Arizona School of Medicine, Tucson, AZ, USA.
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Binkovitz LA, El-Youssef M, Glaser KJ, Yin M, Binkovitz AK, Ehman RL. Pediatric MR elastography of hepatic fibrosis: principles, technique and early clinical experience. Pediatr Radiol 2012; 42:402-9. [PMID: 22120578 PMCID: PMC3352031 DOI: 10.1007/s00247-011-2298-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 10/11/2011] [Accepted: 10/19/2011] [Indexed: 12/22/2022]
Abstract
Numerous pediatric conditions result in hepatic fibrosis. As treatments develop for the underlying disorders, a non-invasive assessment of liver fibrosis would be beneficial as an adjunct or possible replacement for the traditional gold standard, liver biopsy. Magnetic resonance elastography is a noninvasive imaging technique that has been used successfully in adults for identification and assessment of liver fibrosis. This review describes the basic principles of MR elastography as well as the technical aspects specific to children. Clinical pediatric applications, limitations and areas for future research are described.
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Affiliation(s)
- Larry A Binkovitz
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
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Kolipaka A, Woodrum D, Araoz PA, Ehman RL. MR elastography of the in vivo abdominal aorta: a feasibility study for comparing aortic stiffness between hypertensives and normotensives. J Magn Reson Imaging 2012; 35:582-6. [PMID: 22045617 PMCID: PMC3401065 DOI: 10.1002/jmri.22866] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 09/29/2011] [Indexed: 12/24/2022] Open
Abstract
PURPOSE To demonstrate feasibility of using MR elastography (MRE) to identify hypertensive changes in the abdominal aorta when compared with normotensives based on the stiffness measurements. MATERIALS AND METHODS MRE was performed on eight volunteers (four normotensives and four hypertensives) to measure the effective stiffness of the abdominal aorta. MRE wave images are directionally filtered and phase gradient analysis was performed to determine the stiffness of the aorta. Student's t-test was performed to determine significant difference in stiffness measurements between normotensives and hypertensives. RESULTS The normotensive group demonstrated a mean abdominal aortic stiffness of 3.7 ± 0.8 kPa, while the controlled-hypertensive demonstrated a mean abdominal aortic stiffness of 9.3 ± 1.9 kPa. MRE effective stiffness of abdominal aorta in hypertensives was significantly greater than that of normotensives with p = 0.02. CONCLUSION Feasibility of in vivo aortic MRE is demonstrated. Hypertensives have significantly higher aortic stiffness assessed through MRE than normotensives.
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Nenadic IZ, Urban MW, Aristizabal S, Mitchell SA, Humphrey TC, Greenleaf JF. On Lamb and Rayleigh wave convergence in viscoelastic tissues. Phys Med Biol 2012; 56:6723-38. [PMID: 21970846 DOI: 10.1088/0031-9155/56/20/014] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Characterization of the viscoelastic material properties of soft tissue has become an important area of research over the last two decades. Our group has been investigating the feasibility of using a shear wave dispersion ultrasound vibrometry (SDUV) method to excite Lamb waves in organs with plate-like geometry to estimate the viscoelasticity of the medium of interest. The use of Lamb wave dispersion ultrasound vibrometry to quantify the mechanical properties of viscoelastic solids has previously been reported. Two organs, the heart wall and the spleen, can be readily modeled using plate-like geometries. The elasticity of these two organs is important because they change in pathological conditions. Diastolic dysfunction is the inability of the left ventricle (LV) of the heart to supply sufficient stroke volumes into the systemic circulation and is accompanied by the loss of compliance and stiffening of the LV myocardium. It has been shown that there is a correlation between high splenic stiffness in patients with chronic liver disease and strong correlation between spleen and liver stiffness. Here, we investigate the use of the SDUV method to quantify the viscoelasticity of the LV free-wall myocardium and spleen by exciting Rayleigh waves on the organ's surface and measuring the wave dispersion (change of wave velocity as a function of frequency) in the frequency range 40–500 Hz. An equation for Rayleigh wave dispersion due to cylindrical excitation was derived by modeling the excised myocardium and spleen with a homogenous Voigt material plate immersed in a nonviscous fluid. Boundary conditions and wave potential functions were solved for the surface wave velocity. Analytical and experimental convergence between the Lamb and Rayleigh waves is reported in a finite element model of a plate in a fluid of similar density, gelatin plate and excised porcine spleen and left-ventricular free-wall myocardium.
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Affiliation(s)
- Ivan Z Nenadic
- Department of Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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Bensamoun SF, Robert L, Leclerc GE, Debernard L, Charleux F. Stiffness imaging of the kidney and adjacent abdominal tissues measured simultaneously using magnetic resonance elastography. Clin Imaging 2011; 35:284-7. [PMID: 21724121 DOI: 10.1016/j.clinimag.2010.07.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 06/25/2010] [Indexed: 11/18/2022]
Abstract
To date, non-invasive methods to detect kidney malignancies and mild tumors remain a challenge. The purpose of this study was to establish the proper imaging protocol to determine kidney stiffness and its spatial distribution within the various kidney compartments such as the renal sinus, medulla, and cortex. Here, we have used magnetic resonance elastography (MRE) along with coronal oblique acquisition to simultaneously measure kidney stiffness in comparison with other tissues including the liver, spleen, and psoas.
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Affiliation(s)
- Sabine F Bensamoun
- Biomechanics and Bioengineering Laboratory, UMR CNRS 6600, Université de Technologie de Compiègne, Compiègne, France.
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