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Lemine AS, Ahmad Z, Al-Thani NJ, Hasan A, Bhadra J. Mechanical properties of human hepatic tissues to develop liver-mimicking phantoms for medical applications. Biomech Model Mechanobiol 2024; 23:373-396. [PMID: 38072897 DOI: 10.1007/s10237-023-01785-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 10/17/2023] [Indexed: 03/26/2024]
Abstract
Using liver phantoms for mimicking human tissue in clinical training, disease diagnosis, and treatment planning is a common practice. The fabrication material of the liver phantom should exhibit mechanical properties similar to those of the real liver organ in the human body. This tissue-equivalent material is essential for qualitative and quantitative investigation of the liver mechanisms in producing nutrients, excretion of waste metabolites, and tissue deformity at mechanical stimulus. This paper reviews the mechanical properties of human hepatic tissues to develop liver-mimicking phantoms. These properties include viscosity, elasticity, acoustic impedance, sound speed, and attenuation. The advantages and disadvantages of the most common fabrication materials for developing liver tissue-mimicking phantoms are also highlighted. Such phantoms will give a better insight into the real tissue damage during the disease progression and preservation for transplantation. The liver tissue-mimicking phantom will raise the quality assurance of patient diagnostic and treatment precision and offer a definitive clinical trial data collection.
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Affiliation(s)
- Aicha S Lemine
- Department of Mechanical and Industrial Engineering, College of Engineering, Qatar University, 2713, Doha, Qatar
- Qatar University Young Scientists Center (QUYSC), Qatar University, 2713, Doha, Qatar
| | - Zubair Ahmad
- Qatar University Young Scientists Center (QUYSC), Qatar University, 2713, Doha, Qatar
- Center for Advanced Materials (CAM), Qatar University, PO Box 2713, Doha, Qatar
| | - Noora J Al-Thani
- Qatar University Young Scientists Center (QUYSC), Qatar University, 2713, Doha, Qatar
| | - Anwarul Hasan
- Department of Mechanical and Industrial Engineering, College of Engineering, Qatar University, 2713, Doha, Qatar
| | - Jolly Bhadra
- Qatar University Young Scientists Center (QUYSC), Qatar University, 2713, Doha, Qatar.
- Center for Advanced Materials (CAM), Qatar University, PO Box 2713, Doha, Qatar.
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2
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Mik P, Barannikava K, Surkova P. Biased Quantification of Rat Liver Fibrosis-Meta-Analysis with Practical Recommendations and Clinical Implications. J Clin Med 2023; 12:5072. [PMID: 37568474 PMCID: PMC10420125 DOI: 10.3390/jcm12155072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/21/2023] [Accepted: 07/29/2023] [Indexed: 08/13/2023] Open
Abstract
For liver fibrosis assessment, the liver biopsy is usually stained with Masson's trichrome (MT) or picrosirius red (PSR) to quantify liver connective tissue (LCT) for fibrosis scoring. However, several concerns of such semiquantitative assessments have been raised, and when searching for data on the amount of LCT in healthy rats, the results vastly differ. Regarding the ongoing reproducibility crisis in science, it is necessary to inspect the results and methods, and to design an unbiased and reproducible method of LCT assessment. We searched the Medline database using search terms related to liver fibrosis, LCT and collagen, rat strains, and staining methods. Our search identified 74 eligible rat groups in 57 studies. We found up to 170-fold differences in the amount of LCT among healthy Wistar and Sprague-Dawley rats, with significant differences even within individual studies. Biased sampling and quantification probably caused the observed differences. In addition, we also found incorrect handling of liver fibrosis scoring. Assessment of LCT using stereological sampling methods (such as systematic uniform sampling) would provide us with unbiased data. Such data could eventually be used not only for the objective assessment of liver fibrosis but also for validation of noninvasive methods of the assessment of early stages of liver fibrosis.
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Affiliation(s)
- Patrik Mik
- Department of Anatomy, Faculty of Medicine in Pilsen, Charles University, alej Svobody 76, 323 00 Pilsen, Czech Republic
- Biomedical Center and Department of Histology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 76, 323 00 Pilsen, Czech Republic
| | - Katsiaryna Barannikava
- Department of Anatomy, Faculty of Medicine in Pilsen, Charles University, alej Svobody 76, 323 00 Pilsen, Czech Republic
| | - Polina Surkova
- Department of Anatomy, Faculty of Medicine in Pilsen, Charles University, alej Svobody 76, 323 00 Pilsen, Czech Republic
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3
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Owen H, Jones E, Kowald C, Hand S, McGowan M, Cobbold R, Barnes TS, Gibson JS, Ranjbar S, Palmieri C, Allavena R. Development and application of a new liver pathology recording system for use in cattle abattoirs. Res Vet Sci 2023; 158:164-184. [PMID: 37023570 DOI: 10.1016/j.rvsc.2023.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 02/01/2023] [Accepted: 03/02/2023] [Indexed: 03/12/2023]
Abstract
Liver disease in beef cattle has a significant global economic impact on feedlot and abattoir industries due to reduced animal performance, carcase yield, and carcase quality. This study aimed to create a post-mortem data collection tool which could be deployed at chain speed on an abattoir floor, as well as to evaluate pathological findings in both normal and condemned livers from an Australian beef cattle population. The first 1006 livers were used to formulate a user-friendly, high-throughput liver grading tool for use in an abattoir setting and to evaluate the histological features of common liver abnormalities. Subsequently, over 11,000 livers from a Southeast Queensland abattoir were analyzed. The most observed defects in condemned livers were liver abscessation, fibrosis, adhesions, and liver fluke, with histological features similar to previous reports. Bacterial culture was performed in 29 cases of liver abscessation, revealing a different balance of flora to that reported internationally. This study has developed an easy to use, efficient data collection tool that enables rapid, highly detailed assessment of large numbers of beef cattle livers at slaughter. This tool will allow thorough investigation into the effect of liver disease on beef production, in both industry and research contexts.
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Affiliation(s)
- Helen Owen
- The University of Queensland, School of Veterinary Science, Gatton, QLD 4343, Australia
| | - Emily Jones
- The University of Queensland, School of Veterinary Science, Gatton, QLD 4343, Australia.
| | - Carla Kowald
- The University of Queensland, School of Veterinary Science, Gatton, QLD 4343, Australia
| | - Sebastian Hand
- The University of Queensland, School of Veterinary Science, Gatton, QLD 4343, Australia
| | - Michael McGowan
- The University of Queensland, School of Veterinary Science, Gatton, QLD 4343, Australia
| | - Rowland Cobbold
- The University of Queensland, School of Veterinary Science, Gatton, QLD 4343, Australia
| | - Tamsin S Barnes
- The University of Queensland, School of Veterinary Science, Gatton, QLD 4343, Australia
| | - Justine S Gibson
- The University of Queensland, School of Veterinary Science, Gatton, QLD 4343, Australia
| | - Shahab Ranjbar
- The University of Queensland, School of Veterinary Science, Gatton, QLD 4343, Australia
| | - Chiara Palmieri
- The University of Queensland, School of Veterinary Science, Gatton, QLD 4343, Australia
| | - Rachel Allavena
- The University of Queensland, School of Veterinary Science, Gatton, QLD 4343, Australia
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4
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Quasi-Static Mechanical Properties and Continuum Constitutive Model of the Thyroid Gland. J Funct Biomater 2022; 13:jfb13040283. [PMID: 36547544 PMCID: PMC9783632 DOI: 10.3390/jfb13040283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 11/30/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022] Open
Abstract
The purpose of this study is to obtain the digital twin parameters of the thyroid gland and to build a constitutional model of the thyroid gland based on continuum mechanics, which will lay the foundation for the establishment of a surgical training system for the thyroid surgery robot and the development of the digital twin of the thyroid gland. First, thyroid parenchyma was obtained from fresh porcine thyroid tissue and subjected to quasi-static unconfined uniaxial compression tests using a biomechanical test platform with two strain rates (0.005 s-1 and 0.05 s-1) and two loading orientations (perpendicular to the thyroid surface and parallel to the thyroid surface). Based on this, a tensile thyroid model was established to simulate the stretching process by using the finite element method. The thyroid stretching test was carried out under the same parameters to verify the validity of the hyperelastic constitutive model. The quasi-static mechanical property parameters of the thyroid tissue were obtained by a quasi-static unconstrained uniaxial compression test, and a constitutional model that can describe the quasi-static mechanical properties of thyroid tissue was proposed based on the principle of continuum media mechanics, which is of great value for the establishment of a surgical training system for the head and neck surgery robot and for the development of the thyroid digital twin.
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Lunova M, Frankova S, Gottfriedova H, Senkerikova R, Neroldova M, Kovac J, Kieslichova E, Lanska V, Sticova E, Spicak J, Jirsa M, Sperl J. Portal hypertension is the main driver of liver stiffness in advanced liver cirrhosis. Physiol Res 2021; 70:563-577. [PMID: 34062072 DOI: 10.33549/physiolres.934626] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Liver stiffness (LS) is a novel non-invasive parameter widely used in clinical hepatology. LS correlates with liver fibrosis stage in non-cirrhotic patients. In cirrhotic patients it also shows good correlation with Hepatic Venous Pressure Gradient (HVPG). Our aim was to assess the contribution of liver fibrosis and portal hypertension to LS in patients with advanced liver cirrhosis. Eighty-one liver transplant candidates with liver cirrhosis of various aetiologies underwent direct HVPG and LS measurement by 2D shear-wave elastography (Aixplorer Multiwave, Supersonic Imagine, France). Liver collagen content was assessed in the explanted liver as collagen proportionate area (CPA) and hydroxyproline content (HP). The studied cohort included predominantly patients with Child-Pugh class B and C (63/81, 77.8%), minority of patients were Child-Pugh A (18/81, 22.2%). LS showed the best correlation with HVPG (r=0.719, p< 0.001), correlation of LS with CPA (r=0.441, p< 0.001) and HP/Amino Acids (r=0.414, p< 0.001) was weaker. Both variables expressing liver collagen content showed good correlation with each other (r=0.574, p<0.001). Multiple linear regression identified the strongest association between LS and HVPG (p < 0.0001) and weaker association of LS with CPA (p = 0.01883). Stepwise modelling showed minimal increase in r2 after addition of CPA to HVPG (0.5073 vs. 0.5513). The derived formula expressing LS value formation is: LS = 2.48 + (1.29 x HVPG) + (0.26 x CPA). We conclude that LS is determined predominantly by HVPG in patients with advanced liver cirrhosis whereas contribution of liver collagen content is relatively low.
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Affiliation(s)
- M Lunova
- Department of Hepatogastroenterology, Transplant Centre; Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
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Mărginean CO, Meliţ LE, Huţanu A, Ghiga DV, Săsăran MO. The gap between overweight and obesity status in children - (STROBE-compliant article). Medicine (Baltimore) 2021; 100:e24520. [PMID: 33530279 PMCID: PMC7850705 DOI: 10.1097/md.0000000000024520] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 01/08/2021] [Indexed: 12/27/2022] Open
Abstract
Overweight might represent only the early stage of obesity or it might act as a trigger of self-awareness turning into an ideal chance for preventing further obesity development.The aim of this study was to assess the differences between overweight and obese children in terms of anthropometric, low-grade systemic inflammation, liver impairment and atherosclerotic risk.We performed a study on 132 children aged between 5 and 18 years, divided according to the BMI into 2 groups: group 1 to 76 obese children, and group 2 to 56 overweight children, assessing anthropometric, laboratory and elastography parameters.We obtained significantly higher values of anthropometric parameters in obese children versus overweight ones. We found higher levels of leukocytes, lymphocytes, AST, ALT, and E median (P = .0345, P = .0103, P < .0001, P = .0008 and P < .0001) in the obese group as compared to the overweight one. BMI was positively correlated with neutrophils, NLR, ESR, glycemia, anthropometric parameters, and E median (P = .0007/<.0001/.0018/.0044/<.0001/<.0001/<.0001/<.0001/<.0001/.0204); and negatively with lymphocytes and HDL-cholesterol (r = -0.2747/-0.2181, P = .0116/.0120).Our study underlined significant differences between overweight and obese children in terms of inflammatory status and liver impairment suggesting that the risk is directly related to the increase in BMI.
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Affiliation(s)
| | | | - Adina Huţanu
- Research Laboratory, Center for Advanced Medical and Pharmaceutical Research
| | | | - Maria Oana Săsăran
- Department of Pediatric III, “George Emil Palade” University of Medicine, Pharmacy, Sciences and Technology from Târgu Mureş, Gheorghe Marinescu Street No 38, Romania
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Li DK, Khan MR, Wang Z, Chongsrisawat V, Swangsak P, Teufel-Schäfer U, Engelmann G, Goldschmidt I, Baumann U, Tokuhara D, Cho Y, Rowland M, Mjelle AB, Ramm GA, Lewindon PJ, Witters P, Cassiman D, Ciuca IM, Prokop LD, Haffar S, Corey KE, Murad MH, Furuya KN, Bazerbachi F. Normal liver stiffness and influencing factors in healthy children: An individual participant data meta-analysis. Liver Int 2020; 40:2602-2611. [PMID: 32901449 DOI: 10.1111/liv.14658] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 08/20/2020] [Accepted: 08/22/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Although transient elastography (TE) is used to determine liver stiffness as a surrogate to hepatic fibrosis, the normal range in children is not well defined. We performed a systematic review and individual participant data (IPD) meta-analysis to determine the range of liver stiffness in healthy children and evaluate the influence of important biological parameters. METHODS We pooled data from 10 studies that examined healthy children using TE. We divided 1702 children into two groups: ≥3 years (older group) and < 3 years of age (younger group). Univariate and multivariate linear regression models predicting liver stiffness were conducted. RESULTS After excluding children with obesity, diabetes, or abnormal liver tests, 652 children were analysed. Among older children, mean liver stiffness was 4.45 kPa (95% confidence interval 4.34-4.56), and increased liver stiffness was associated with age, sedation status, and S probe use. In the younger group, the mean liver stiffness was 4.79 kPa (95% confidence interval 4.46-5.12), and increased liver stiffness was associated with sedation status and Caucasian race. In a subgroup analysis, hepatic steatosis on ultrasound was significantly associated with increased liver stiffness. We define a reference range for normal liver stiffness in healthy children as 2.45-5.56 kPa. CONCLUSIONS We have established TE-derived liver stiffness ranges for healthy children and propose an upper limit of liver stiffness in healthy children to be 5.56 kPa. We have identified increasing age, use of sedation, probe size, and presence of steatosis on ultrasound as factors that can significantly increase liver stiffness.
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Affiliation(s)
- Darrick K Li
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Muhammad Rehan Khan
- Division of Pediatric Gastroenterology, Hepatology and Nutrition, University of Illinois College of Medicine at Peoria, Children's Hospital of Illinois, Peoria, IL, USA
| | - Zhen Wang
- Evidence-Based Practice Center, Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN, USA
| | - Voranush Chongsrisawat
- Department of Pediatrics, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Panida Swangsak
- Department of Pediatrics, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Ulrike Teufel-Schäfer
- Department of Pediatrics and Adolescent Medicine, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | | | - Imeke Goldschmidt
- Division of Paediatric Gastroenterology and Hepatology, Hannover Medical School, Hannover, Germany
| | - Ulrich Baumann
- Division of Paediatric Gastroenterology and Hepatology, Hannover Medical School, Hannover, Germany.,Institute of Immunology and Immunotherapy, University of Birmingham, United Kingdom
| | - Daisuke Tokuhara
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Yuki Cho
- Department of Pediatrics, Osaka City University Graduate School of Medicine, Osaka, Japan
| | - Marion Rowland
- School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Anders B Mjelle
- Department of Pediatric and Adolescent Medicine, Haukeland University Hospital, Bergen, Norway.,Department of Clinical Medicine, University of Bergen, Bergen, Norway.,National Centre for Ultrasound in Gastroenterology, Department of Medicine, Haukeland University Hospital, Bergen, Norway
| | - Grant A Ramm
- Hepatic Fibrosis Group, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Peter J Lewindon
- Department of Gastroenterology, Hepatology and Liver Transplant, Queensland Children's Hospital, Brisbane, Australia
| | - Peter Witters
- Department of Paediatrics, University Hospitals Leuven, Leuven, Belgium
| | - David Cassiman
- Department of Gastroenterology-Hepatology and Metabolic Center, University of Leuven, Leuven, Belgium
| | - Ioana M Ciuca
- Pediatrics Department, University of Medicine and Pharmacy "Victor Babes", Timisoara, Romania
| | - Larry D Prokop
- Evidence-Based Practice Center, Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN, USA
| | - Samir Haffar
- Digestive Center for Diagnosis and Treatment, Damascus, Syrian Arab Republic
| | - Kathleen E Corey
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - M H Murad
- Evidence-Based Practice Center, Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester, MN, USA
| | - Katryn N Furuya
- Department of Pediatrics, University of Wisconsin - Madison School of Medicine and Public Health, Madison, WI, USA
| | - Fateh Bazerbachi
- Division of Gastroenterology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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Baldini F, Bartolozzi A, Ardito M, Voci A, Portincasa P, Vassalli M, Vergani L. Biomechanics of cultured hepatic cells during different steatogenic hits. J Mech Behav Biomed Mater 2019; 97:296-305. [PMID: 31151002 DOI: 10.1016/j.jmbbm.2019.05.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 05/16/2019] [Accepted: 05/21/2019] [Indexed: 12/20/2022]
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Kruepunga N, Hakvoort TB, Hikspoors JP, Köhler SE, Lamers WH. Anatomy of rodent and human livers: What are the differences? Biochim Biophys Acta Mol Basis Dis 2019; 1865:869-878. [DOI: 10.1016/j.bbadis.2018.05.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 04/30/2018] [Accepted: 05/22/2018] [Indexed: 12/17/2022]
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10
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Li T, Li L, Liu Z. Time Course Changes of the Mechanical Properties of the Iris Pigment Epithelium in a Rat Chronic Ocular Hypertension Model. BIOMED RESEARCH INTERNATIONAL 2018; 2018:4862309. [PMID: 30420963 PMCID: PMC6215589 DOI: 10.1155/2018/4862309] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/06/2018] [Accepted: 10/01/2018] [Indexed: 01/04/2023]
Abstract
BACKGROUND The flow field of aqueous humor correlates to the stiffness of iris pigment epithelium (IPE) which acts as a wall of posterior chamber. We focus on the variations of IPE stiffness in a rat ocular hypertension (OHT) model, so as to prepare for exploring the mechanism of duration of OHT. METHODS Episcleral venous cauterization (EVC) was applied on one eye of male adult Sprague-Dawley rats to induce chronic high intraocular pressure. According to the duration of OHT (0, 1, 2, 4, and 8 weeks), rats were randomly divided into Gw0, Gw1, Gw2, Gw4, and Gw8. Atomic force microscope (AFM) analysis was applied to test IPE stiffness in three regions: iris root, mid-periphery, and pupillary-margin in each group. Histological changes of IPE were also examined in Gw4 and Gw8. RESULTS There was an overall growing tendency of IPE stiffness in EVC eye. IPE in EVC eye was significantly stiffer than fellow eye in Gw2, Gw4, and Gw8 (in iris root, mid-periphery, and pupillary-margin, p<0.05). IPE in EVC eye in pupillary-margin was significantly stiffer than iris root in Gw4 and Gw8 (p<0.05). In EVC eye, IPE becomes thinner and IPE cell density decreases. CONCLUSION IPE stiffness increases gradually with the duration of chronic high intraocular pressure.
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Affiliation(s)
- Tan Li
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, China
| | - Lin Li
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, China
| | - Zhicheng Liu
- School of Biomedical Engineering, Capital Medical University, Beijing 100069, China
- Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, China
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11
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Study on the Effect and the Eliminate Method of Preloading Force on the Compression Tests of Liver Tissue. J Med Biol Eng 2018. [DOI: 10.1007/s40846-018-0438-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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12
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Palacio‐Torralba J, Good DW, Stewart GD, McNeill SA, Reuben RL, Chen Y. A novel method for rapid and quantitative mechanical assessment of soft tissue for diagnostic purposes: A computational study. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e2917. [PMID: 28753220 PMCID: PMC5836875 DOI: 10.1002/cnm.2917] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 06/23/2017] [Accepted: 07/20/2017] [Indexed: 05/07/2023]
Abstract
Biological tissues often experience drastic changes in their microstructure due to their pathophysiological conditions. Such microstructural changes could result in variations in mechanical properties, which can be used in diagnosing or monitoring a wide range of diseases, most notably cancer. This paves the avenue for non-invasive diagnosis by instrumented palpation although challenges remain in quantitatively assessing the amount of diseased tissue by means of mechanical characterization. This paper presents a framework for tissue diagnosis using a quantitative and efficient estimation of the fractions of cancerous and non-cancerous tissue without a priori knowledge of tissue microstructure. First, the sample is tested in a creep or stress relaxation experiment, and the behavior is characterized using a single term Prony series. A rule of mixtures, which relates tumor fraction to the apparent mechanical properties, is then obtained by minimizing the difference between strain energy of a heterogeneous system and an equivalent homogeneous one. Finally, the percentage of each tissue constituent is predicted by comparing the observed relaxation time with that calculated from the rule of mixtures. The proposed methodology is assessed using models reconstructed from histological samples and magnetic resonance imaging of prostate. Results show that estimation of cancerous tissue fraction can be obtained with a maximum error of 12% when samples of different sizes, geometries, and tumor fractions are presented. The proposed framework has the potential to be applied to a wide range of diseases such as rectal polyps, cirrhosis, or breast and prostate cancer whose current primary diagnosis remains qualitative.
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Affiliation(s)
- Javier Palacio‐Torralba
- Institute of Mechanical, Process, and Energy Engineering, School of Engineering and Physical SciencesHeriot‐Watt UniversityEdinburghEH14 4ASUK
| | - Daniel W. Good
- Edinburgh Urological Cancer Group, Division of Pathology Laboratories, Institute of Genetics and Molecular MedicineUniversity of EdinburghWestern General Hospital, Crewe Road SouthEdinburghEH4 2XUUK
| | - Grant D. Stewart
- Edinburgh Urological Cancer Group, Division of Pathology Laboratories, Institute of Genetics and Molecular MedicineUniversity of EdinburghWestern General Hospital, Crewe Road SouthEdinburghEH4 2XUUK
- Department of Urology, NHS LothianWestern General HospitalCrewe Road SouthEdinburghEH4 2XUUK
| | - S. Alan McNeill
- Edinburgh Urological Cancer Group, Division of Pathology Laboratories, Institute of Genetics and Molecular MedicineUniversity of EdinburghWestern General Hospital, Crewe Road SouthEdinburghEH4 2XUUK
- Department of Urology, NHS LothianWestern General HospitalCrewe Road SouthEdinburghEH4 2XUUK
| | - Robert L. Reuben
- Institute of Mechanical, Process, and Energy Engineering, School of Engineering and Physical SciencesHeriot‐Watt UniversityEdinburghEH14 4ASUK
| | - Yuhang Chen
- Institute of Mechanical, Process, and Energy Engineering, School of Engineering and Physical SciencesHeriot‐Watt UniversityEdinburghEH14 4ASUK
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Zhang HM, Wang Y, Fatemi M, Insana MF. Assessing composition and structure of soft biphasic media from Kelvin-Voigt fractional derivative model parameters. MEASUREMENT SCIENCE & TECHNOLOGY 2017; 28:035703. [PMID: 28239236 PMCID: PMC5319561 DOI: 10.1088/1361-6501/aa5531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Kelvin-Voigt fractional derivative (KVFD) model parameters have been used to describe viscoelastic properties of soft tissues. However, translating model parameters into a concise set of intrinsic mechanical properties related to tissue composition and structure remains challenging. This paper begins by exploring these relationships using a biphasic emulsion materials with known composition. Mechanical properties are measured by analyzing data from two indentation techniques - ramp-stress relaxation and load-unload hysteresis tests. Material composition is predictably correlated with viscoelastic model parameters. Model parameters estimated from the tests reveal that elastic modulus E0 closely approximates the shear modulus for pure gelatin. Fractional-order parameter α and time constant τ vary monotonically with the volume fraction of the material's fluid component. α characterizes medium fluidity and the rate of energy dissipation, and τ is a viscous time constant. Numerical simulations suggest that the viscous coefficient η is proportional to the energy lost during quasi-static force-displacement cycles, EA . The slope of EA versus η is determined by α and the applied indentation ramp time Tr. Experimental measurements from phantom and ex vivo liver data show close agreement with theoretical predictions of the η - EA relation. The relative error is less than 20% for emulsions 22% for liver. We find that KVFD model parameters form a concise features space for biphasic medium characterization that described time-varying mechanical properties.
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Affiliation(s)
- Hong Mei Zhang
- Key Laboratory of Biomedical Information Engineering, Ministry of Education, School of Life Science and Technology, Xi'an JiaoTong University, Xianning West Road No.28, Xi'an, Shaanxi, 710049, P. R. China; Department of Bioengineering and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana IL, 61801, USA
| | - Yue Wang
- Department of Bioengineering and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana IL, 61801, USA
| | - Mostafa Fatemi
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Michael F Insana
- Department of Bioengineering and Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana IL, 61801, USA
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Influence of clamping stress and duration on the trauma of liver tissue during surgery operation. Clin Biomech (Bristol, Avon) 2017; 43:58-66. [PMID: 28213166 DOI: 10.1016/j.clinbiomech.2017.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 02/06/2017] [Accepted: 02/07/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND Tissue grasping damage often occurs in minimally invasive surgery, which would increase the postoperative recovery time and the risk of surgical complications. The purpose of this study was to evaluate the relationship between liver tissue trauma and compression stress magnitude and duration during tissue clamping operation. METHODS The clamping experiments of liver tissues in vivo were conducted by using a universal soft tissue mechanical testing machine under different clamping stress magnitudes and durations. The rabbit liver was used to simulate human liver. A minimally invasive surgery grasper was used in these tests to simulate the real tissue-surgical operation condition. A pathological grading system was created to quantitatively assess the trauma within the liver tissue. The hyperbolic regression models were utilized to predict the trauma degree of liver tissue. FINDINGS Obvious hyperemia, hemorrhage, hepatic capsule rupture and inflammatory cell infiltration appeared in the clamping sites of the liver. Assessment results indicated that the trauma degree increased nonlinearly with the increasing clamping stress and duration time. There exist safe thresholds, in which the severe trauma of the studied tissue can be avoided during grasping operation. INTERPRETATION The results could provide the safety margins and the trauma prediction models for surgeons during grasping and palpation tasks in minimally invasive surgery.
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Etchell E, Jugé L, Hatt A, Sinkus R, Bilston LE. Liver Stiffness Values Are Lower in Pediatric Subjects than in Adults and Increase with Age: A Multifrequency MR Elastography Study. Radiology 2016; 283:222-230. [PMID: 27755913 DOI: 10.1148/radiol.2016160252] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Purpose To determine if healthy hepatic mechanical properties differ between pediatric and adult subjects at magnetic resonance (MR) elastography. Materials and Methods Liver shear moduli in 24 healthy pediatric participants (13 children aged 5-14 years [seven boys, six girls] and 11 adolescents aged 15-18 years [six boys, five girls]) and 10 healthy adults (aged 22-36 years [five men, five women]) were obtained with 3-T MR elastography at 28, 56, and 84 Hz. Relationships between shear moduli and age were assessed with Spearman correlations. Differences between age groups were determined with one-way analysis of variance and Tukey multiple comparisons tests. Results Liver stiffness values (means ± standard deviations) were significantly lower in children and adolescents than in adults at 56 Hz (children, 2.2 kPa ± 0.3; adolescents, 2.2 kPa ± 0.2; adults, 2.6 kPa ± 0.3; analysis of variance, P = .009) and 84 Hz (children, 5.6 kPa ± 0.8; adolescents, 6.5 kPa ± 1.2; adults, 7.8 kPa ± 1.2; analysis of variance, P = .0003) but not at 28 Hz (children, 1.2 kPa ± 0.2; adolescents, 1.3 kPa ± 0.3; adults, 1.2 kPa ± 0.2; analysis of variance, P = .40). At 56 and 84 Hz, liver stiffness increased with age (Spearman correlation, r = 0.38 [P = .03] and r = 0.54 [P = .001], respectively). Stiffness varied less with frequency in children and adolescents than in adults (analysis of variance, P = .0009). No significant differences were found in shear moduli at 28, 56, or 84 Hz or frequency dependence between children and adolescents (P = .38, P = .99, P = .14, and P = .30, respectively, according to Tukey tests). Conclusion Liver stiffness values are lower and vary less with frequency in children and adolescents than in adults. Stiffness increases with age during normal development and approaches adult values during adolescence. Comparing pediatric liver stiffness to adult baseline values to detect pediatric liver mechanical abnormalities may not allow detection of mild disease and may lead to underestimation of severity. © RSNA, 2016 Online supplemental material is available for this article.
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Affiliation(s)
- Emily Etchell
- From Neuroscience Research Australia, Margarete Ainsworth Building, Barker St, Randwick, NSW 2031, Australia (E.E., L.J., A.H., L.E.B.); and Department of Biomedical Engineering, King's College London, London, England (R.S.)
| | - Lauriane Jugé
- From Neuroscience Research Australia, Margarete Ainsworth Building, Barker St, Randwick, NSW 2031, Australia (E.E., L.J., A.H., L.E.B.); and Department of Biomedical Engineering, King's College London, London, England (R.S.)
| | - Alice Hatt
- From Neuroscience Research Australia, Margarete Ainsworth Building, Barker St, Randwick, NSW 2031, Australia (E.E., L.J., A.H., L.E.B.); and Department of Biomedical Engineering, King's College London, London, England (R.S.)
| | - Ralph Sinkus
- From Neuroscience Research Australia, Margarete Ainsworth Building, Barker St, Randwick, NSW 2031, Australia (E.E., L.J., A.H., L.E.B.); and Department of Biomedical Engineering, King's College London, London, England (R.S.)
| | - Lynne E Bilston
- From Neuroscience Research Australia, Margarete Ainsworth Building, Barker St, Randwick, NSW 2031, Australia (E.E., L.J., A.H., L.E.B.); and Department of Biomedical Engineering, King's College London, London, England (R.S.)
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Mauri A, Ehret AE, De Focatiis DSA, Mazza E. A model for the compressible, viscoelastic behavior of human amnion addressing tissue variability through a single parameter. Biomech Model Mechanobiol 2015; 15:1005-17. [DOI: 10.1007/s10237-015-0739-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 10/09/2015] [Indexed: 10/22/2022]
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Ayyildiz M, Cinoglu S, Basdogan C. Effect of normal compression on the shear modulus of soft tissue in rheological measurements. J Mech Behav Biomed Mater 2015; 49:235-43. [DOI: 10.1016/j.jmbbm.2015.05.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 05/02/2015] [Accepted: 05/13/2015] [Indexed: 11/24/2022]
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Mechanics of Biological Tissues and Biomaterials: Current Trends. MATERIALS 2015; 8:4505-4511. [PMID: 28793452 PMCID: PMC5455625 DOI: 10.3390/ma8074505] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 07/03/2015] [Accepted: 07/17/2015] [Indexed: 11/29/2022]
Abstract
Investigation of the mechanical behavior of biological tissues and biomaterials has been an active area of research for several decades. However, in recent years, the enthusiasm in understanding the mechanical behavior of biological tissues and biomaterials has increased significantly due to the development of novel biomaterials for new fields of application, along with the emergence of advanced computational techniques. The current Special Issue is a collection of studies that address various topics within the general theme of “mechanics of biomaterials”. This editorial aims to present the context within which the studies of this Special Issue could be better understood. I, therefore, try to identify some of the most important research trends in the study of the mechanical behavior of biological tissues and biomaterials.
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Finite element analysis for evaluating liver tissue damage due to mechanical compression. J Biomech 2015; 48:948-55. [PMID: 25748221 DOI: 10.1016/j.jbiomech.2015.02.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 02/06/2015] [Accepted: 02/15/2015] [Indexed: 11/23/2022]
Abstract
The development of robotic-assisted minimally invasive surgery (RMIS) has resulted in increased research to improve surgeon training, proficiency and patient safety. Minimizing tissue damage is an essential consideration in RMIS. Various studies have reported the quantified tissue damage resulting from mechanical compression; however, most of them require bench work analysis, which limits their application in clinical conditions of RMIS. We present a new methodology based on nonlinear finite element (FE) analysis that can predict damage degree inside tissue. The effects of the boundary conditions and material property of the FE model on the simulated von Mises stress value and tissue damage were investigated. Four FE models were analyzed: two-dimensional (2D) plane strain model, 2D plane stress model, full three-dimensional (3D) model, and 3D thin membrane model. Nonlinear material properties of liver tissue used in the FEA were derived from previously reported in vivo and in vitro experiments. Our study showed that for integrated von Mises stress and tissue damage computations, the 3D thin membrane model yielded results closest to the full 3D analysis and required only 0.2% of the compute time. The results from 3D thin membrane and the full 3D models fell below plane-strain model and above the plane-stress model. Both stress and necrosis distributions were impacted by the material property of FE models. This study can guide engineers to design surgical instruments to improve patient safety. Additionally it is useful for improving the surgical simulator performance by reflecting more realistic tissue material property and displaying tissue damage severity.
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Palacio-Torralba J, Hammer S, Good DW, Alan McNeill S, Stewart GD, Reuben RL, Chen Y. Quantitative diagnostics of soft tissue through viscoelastic characterization using time-based instrumented palpation. J Mech Behav Biomed Mater 2014; 41:149-60. [PMID: 25460411 DOI: 10.1016/j.jmbbm.2014.09.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/18/2014] [Accepted: 09/23/2014] [Indexed: 10/24/2022]
Abstract
Although palpation has been successfully employed for centuries to assess soft tissue quality, it is a subjective test, and is therefore qualitative and depends on the experience of the practitioner. To reproduce what the medical practitioner feels needs more than a simple quasi-static stiffness measurement. This paper assesses the capacity of dynamic mechanical palpation to measure the changes in viscoelastic properties that soft tissue can exhibit under certain pathological conditions. A diagnostic framework is proposed to measure elastic and viscous behaviors simultaneously using a reduced set of viscoelastic parameters, giving a reliable index for quantitative assessment of tissue quality. The approach is illustrated on prostate models reconstructed from prostate MRI scans. The examples show that the change in viscoelastic time constant between healthy and cancerous tissue is a key index for quantitative diagnostics using point probing. The method is not limited to any particular tissue or material and is therefore useful for tissue where defining a unique time constant is not trivial. The proposed framework of quantitative assessment could become a useful tool in clinical diagnostics for soft tissue.
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Affiliation(s)
- Javier Palacio-Torralba
- Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Steven Hammer
- Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Daniel W Good
- Edinburgh Urological Cancer Group, Division of Pathology Laboratories, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK
| | - S Alan McNeill
- Edinburgh Urological Cancer Group, Division of Pathology Laboratories, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK; Department of Urology, NHS Lothian, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK
| | - Grant D Stewart
- Edinburgh Urological Cancer Group, Division of Pathology Laboratories, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK; Department of Urology, NHS Lothian, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK
| | - Robert L Reuben
- Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Yuhang Chen
- Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, UK.
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