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Othman SA, Soon CF, Ma NL, Tee KS, Lim GP, Morsin M, Ahmad MK, Abdulmaged AI, Cheong SC. Alginate-gelatin bioink for bioprinting of hela spheroids in alginate-gelatin hexagon shaped scaffolds. Polym Bull (Berl) 2021. [DOI: 10.1007/s00289-020-03421-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Ozturk A, Zubajlo RE, Dhyani M, Grajo JR, Mercaldo N, Anthony BW, Samir AE. Variation of Shear Wave Elastography With Preload in the Thyroid: Quantitative Validation. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2021; 40:779-786. [PMID: 32951229 DOI: 10.1002/jum.15456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 07/23/2020] [Accepted: 07/24/2020] [Indexed: 06/11/2023]
Abstract
OBJECTIVES Thyroid shear wave elastography (SWE) has been shown to have advantages compared to biopsy or other imaging modalities in the evaluation of thyroid nodules. However, studies show variability in its assessment. The objective of this study was to evaluate whether stiffness measurements of the normal thyroid, as estimated by SWE, varied due to preload force or the pressure applied between the transducer and the patient. METHODS In this study, a measurement system was attached to the ultrasound transducer to measure the applied load. Shear wave elastographic measurements were obtained from the left lobe of the thyroid at applied transducer forces between 2 and 10 N. A linear mixed-effects model was constructed to quantify the association between the preload force and stiffness while accounting for correlations between repeated measurements within each participant. The preload force effect on elasticity was modeled by both linear and quadratic terms to account for a possible nonlinear association between these variables. RESULTS Nineteen healthy volunteers without known thyroid disease participated in the study. The participants had a mean age ± SD of 36 ± 8 years; 74% were female; 74% had a normal body mass index; and 95% were white non-Hispanic/Latino. The estimated elastographic value at a 2-N preload force was 16.7 kPa (95% confidence interval, 14.1-19.3 kPa), whereas the value at 10 N was 29.9 kPa (95% confidence interval, 24.9-34.9 kPa). CONCLUSIONS The preload force was significantly and nonlinearly associated with SWE estimates of thyroid stiffness. Quantitative standardization of preload forces in the assessment of thyroid nodules using elastography is an integral factor for improving the accuracy of thyroid nodule evaluation.
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Affiliation(s)
- Arinc Ozturk
- Center for Ultrasound Research & Translation, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Rebecca E Zubajlo
- Department of Mechanical Engineering, Massachusetts Institutes of Technology, Cambridge, Massachusetts, USA
| | - Manish Dhyani
- Department of Radiology, Lahey Hospital and Medical Center, Burlington, Massachusetts, USA
| | - Joseph R Grajo
- Division of Abdominal Imaging, Department of Radiology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Nathaniel Mercaldo
- Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Brian W Anthony
- Department of Mechanical Engineering, Massachusetts Institutes of Technology, Cambridge, Massachusetts, USA
| | - Anthony E Samir
- Center for Ultrasound Research & Translation, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA
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Dynamic Characterization of the Biomechanical Behaviour of Bovine Ovarian Cortical Tissue and Its Short-Term Effect on Ovarian Tissue and Follicles. MATERIALS 2020; 13:ma13173759. [PMID: 32854374 PMCID: PMC7504208 DOI: 10.3390/ma13173759] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/17/2020] [Accepted: 08/20/2020] [Indexed: 11/22/2022]
Abstract
The ovary is a dynamic mechanoresponsive organ. In vitro, tissue biomechanics was reported to affect follicle activation mainly through the Hippo pathway. Only recently, ovary responsiveness to mechanical signals was exploited for reproductive purposes. Unfortunately, poor characterization of ovarian cortex biomechanics and of the mechanical challenge hampers reproducible and effective treatments, and prevention of tissue damages. In this study the biomechanical response of ovarian cortical tissue from abattoir bovines was characterized for the first time. Ovarian cortical tissue fragments were subjected to uniaxial dynamic testing at frequencies up to 30 Hz, and at increasing average stresses. Tissue structure prior to and after testing was characterized by histology, with established fixation and staining protocols, to assess follicle quality and stage. Tissue properties largely varied with the donor. Bovine ovarian cortical tissue consistently exhibited a nonlinear viscoelastic behavior, with dominant elastic characteristics, in the low range of other reproductive tissues, and significant creep. Strain rate was independent of the applied stress. Histological analysis prior to and after mechanical tests showed that the short-term dynamic mechanical test used for the study did not cause significant tissue tear, nor follicle expulsion or cell damage.
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Carlson LC, Hall TJ, Rosado-Mendez IM, Mao L, Feltovich H. Quantitative assessment of cervical softening during pregnancy with shear wave elasticity imaging: an in vivo longitudinal study. Interface Focus 2019; 9:20190030. [PMID: 31485315 PMCID: PMC6710662 DOI: 10.1098/rsfs.2019.0030] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2019] [Indexed: 12/15/2022] Open
Abstract
We report here the results of a longitudinal study of cervix stiffness during pregnancy. Thirty women, ages ranging from 19 to 37 years, were scanned with ultrasound at five time points beginning at their normal first-trimester screening (8-13 weeks) through term pregnancy (nominally 40 week) using a clinical ultrasound imaging system modified with a special ultrasound transducer and system software. The system estimated the shear wave speed (its square proportional to the shear modulus under idealized conditions) in the cervix. We found a constant fractional reduction (about 4% per week) in shear wave speed with increasing gestational age. We also demonstrated a spatial gradient in shear wave speed along the length of the cervix (softest at the distal end). Results were consistent with our previous ex vivo and in vivo work in women. Shear wave elasticity imaging may be a potentially useful clinical tool for objective assessment of cervical softening in pregnancy.
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Affiliation(s)
- Lindsey C. Carlson
- Department of Medical Physics, University of Wisconsin, Madison, WI, USA
- Maternal Fetal Medicine, Intermountain Healthcare, Provo, UT, USA
| | - Timothy J. Hall
- Department of Medical Physics, University of Wisconsin, Madison, WI, USA
| | - Ivan M. Rosado-Mendez
- Department of Medical Physics, University of Wisconsin, Madison, WI, USA
- Institute of Physics, National Autonomous University of Mexico, Mexico City, Mexico
| | - Lu Mao
- Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, WI, USA
| | - Helen Feltovich
- Department of Medical Physics, University of Wisconsin, Madison, WI, USA
- Maternal Fetal Medicine, Intermountain Healthcare, Provo, UT, USA
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5
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Van Hoorick J, Tytgat L, Dobos A, Ottevaere H, Van Erps J, Thienpont H, Ovsianikov A, Dubruel P, Van Vlierberghe S. (Photo-)crosslinkable gelatin derivatives for biofabrication applications. Acta Biomater 2019; 97:46-73. [PMID: 31344513 DOI: 10.1016/j.actbio.2019.07.035] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/20/2019] [Accepted: 07/19/2019] [Indexed: 12/28/2022]
Abstract
Over the recent decades gelatin has proven to be very suitable as an extracellular matrix mimic for biofabrication and tissue engineering applications. However, gelatin is prone to dissolution at typical cell culture conditions and is therefore often chemically modified to introduce (photo-)crosslinkable functionalities. These modifications allow to tune the material properties of gelatin, making it suitable for a wide range of biofabrication techniques both as a bioink and as a biomaterial ink (component). The present review provides a non-exhaustive overview of the different reported gelatin modification strategies to yield crosslinkable materials that can be used to form hydrogels suitable for biofabrication applications. The different crosslinking chemistries are discussed and classified according to their mechanism including chain-growth and step-growth polymerization. The step-growth polymerization mechanisms are further classified based on the specific chemistry including different (photo-)click chemistries and reversible systems. The benefits and drawbacks of each chemistry are also briefly discussed. Furthermore, focus is placed on different biofabrication strategies using either inkjet, deposition or light-based additive manufacturing techniques, and the applications of the obtained 3D constructs. STATEMENT OF SIGNIFICANCE: Gelatin and more specifically gelatin-methacryloyl has emerged to become one of the gold standard materials as an extracellular matrix mimic in the field of biofabrication. However, also other modification strategies have been elaborated to take advantage of a plethora of crosslinking chemistries. Therefore, a review paper focusing on the different modification strategies and processing of gelatin is presented. Particular attention is paid to the underlying chemistry along with the benefits and drawbacks of each type of crosslinking chemistry. The different strategies were classified based on their basic crosslinking mechanism including chain- or step-growth polymerization. Within the step-growth classification, a further distinction is made between click chemistries as well as other strategies. The influence of these modifications on the physical gelation and processing conditions including mechanical properties is presented. Additionally, substantial attention is put to the applied photoinitiators and the different biofabrication technologies including inkjet, deposition or light-based technologies.
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Affiliation(s)
- Jasper Van Hoorick
- Polymer Chemistry & Biomaterials Group - Centre of Macromolecular Chemistry (CMaC) - Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, S4-Bis, 9000 Ghent, Belgium; Brussels Photonics (B-PHOT) - Department of Applied Physics and Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, 1050 Brussels, Belgium
| | - Liesbeth Tytgat
- Polymer Chemistry & Biomaterials Group - Centre of Macromolecular Chemistry (CMaC) - Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, S4-Bis, 9000 Ghent, Belgium; Brussels Photonics (B-PHOT) - Department of Applied Physics and Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, 1050 Brussels, Belgium
| | - Agnes Dobos
- Research Group 3D Printing and Biofabrication, Institute of Materials Science and Technology, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Heidi Ottevaere
- Brussels Photonics (B-PHOT) - Department of Applied Physics and Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, 1050 Brussels, Belgium
| | - Jürgen Van Erps
- Brussels Photonics (B-PHOT) - Department of Applied Physics and Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, 1050 Brussels, Belgium
| | - Hugo Thienpont
- Brussels Photonics (B-PHOT) - Department of Applied Physics and Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, 1050 Brussels, Belgium
| | - Aleksandr Ovsianikov
- Research Group 3D Printing and Biofabrication, Institute of Materials Science and Technology, TU Wien, Getreidemarkt 9, 1060 Vienna, Austria
| | - Peter Dubruel
- Polymer Chemistry & Biomaterials Group - Centre of Macromolecular Chemistry (CMaC) - Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, S4-Bis, 9000 Ghent, Belgium
| | - Sandra Van Vlierberghe
- Polymer Chemistry & Biomaterials Group - Centre of Macromolecular Chemistry (CMaC) - Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, S4-Bis, 9000 Ghent, Belgium; Brussels Photonics (B-PHOT) - Department of Applied Physics and Photonics, Vrije Universiteit Brussel and Flanders Make, Pleinlaan 2, 1050 Brussels, Belgium.
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Qiu K, Zhao Z, Haghiashtiani G, Guo SZ, He M, Su R, Zhu Z, Bhuiyan DB, Murugan P, Meng F, Park SH, Chu CC, Ogle BM, Saltzman DA, Konety BR, Sweet RM, McAlpine MC. 3D Printed Organ Models with Physical Properties of Tissue and Integrated Sensors. ADVANCED MATERIALS TECHNOLOGIES 2018; 3:1700235. [PMID: 29608202 PMCID: PMC5877482 DOI: 10.1002/admt.201700235] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The design and development of novel methodologies and customized materials to fabricate patient-specific 3D printed organ models with integrated sensing capabilities could yield advances in smart surgical aids for preoperative planning and rehearsal. Here, we demonstrate 3D printed prostate models with physical properties of tissue and integrated soft electronic sensors using custom-formulated polymeric inks. The models show high quantitative fidelity in static and dynamic mechanical properties, optical characteristics, and anatomical geometries to patient tissues and organs. The models offer tissue-mimicking tactile sensation and behavior and thus can be used for the prediction of organ physical behavior under deformation. The prediction results show good agreement with values obtained from simulations. The models also allow the application of surgical and diagnostic tools to their surface and inner channels. Finally, via the conformal integration of 3D printed soft electronic sensors, pressure applied to the models with surgical tools can be quantitatively measured.
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Affiliation(s)
- Kaiyan Qiu
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Zichen Zhao
- WWAMI Institute for Simulation in Healthcare, University of Washington, Seattle, Washington 98195, United States
| | - Ghazaleh Haghiashtiani
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Shuang-Zhuang Guo
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Mingyu He
- Fiber Science & Biomedical Engineering Programs, Cornell University, Ithaca, New York 14853, United States
| | - Ruitao Su
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Zhijie Zhu
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Didarul B Bhuiyan
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Paari Murugan
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Fanben Meng
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Sung Hyun Park
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Chih-Chang Chu
- Fiber Science & Biomedical Engineering Programs, Cornell University, Ithaca, New York 14853, United States
| | - Brenda M Ogle
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Daniel A Saltzman
- Department of Surgery, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Badrinath R Konety
- Department of Urology, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Robert M Sweet
- WWAMI Institute for Simulation in Healthcare, University of Washington, Seattle, Washington 98195, United States
| | - Michael C McAlpine
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, United States
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7
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Rosado-Mendez IM, Palmeri ML, Drehfal LC, Guerrero QW, Simmons H, Feltovich H, Hall TJ. Assessment of Structural Heterogeneity and Viscosity in the Cervix Using Shear Wave Elasticity Imaging: Initial Results from a Rhesus Macaque Model. ULTRASOUND IN MEDICINE & BIOLOGY 2017; 43:790-803. [PMID: 28189282 PMCID: PMC5348278 DOI: 10.1016/j.ultrasmedbio.2016.12.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 11/02/2016] [Accepted: 12/14/2016] [Indexed: 05/13/2023]
Abstract
Shear wave elasticity imaging has shown promise in evaluation of the pregnant cervix. Changes in shear wave group velocity have been attributed exclusively to changes in stiffness. This assumes homogeneity within the region of interest and purely elastic tissue behavior. However, the cervix is structurally/microstructurally heterogeneous and viscoelastic. We therefore developed strategies to investigate these complex tissue properties. Shear wave elasticity imaging was performed ex vivo on 14 unripened and 13 misoprostol-ripened cervix specimens from rhesus macaques. After tests of significant and uniform shear wave displacement, as well as reliability of estimates, group velocity decreased significantly from the distal (vaginal) to proximal (uterine) end of unripened, but not ripened, specimens. Viscosity was quantified by the slope of the phase velocity versus frequency. Dispersion was observed in both groups (median: 5.5 m/s/kHz, interquartile range: 1.5-12.0 m/s/kHz), also decreasing toward the proximal cervix. This work suggests that comprehensive assessment of complex tissues such as cervix requires consideration of structural heterogeneity and viscosity.
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Affiliation(s)
- Ivan M Rosado-Mendez
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA.
| | - Mark L Palmeri
- Biomedical Engineering, Duke University, Durham, North Carolina, USA
| | - Lindsey C Drehfal
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Quinton W Guerrero
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Heather Simmons
- Wisconsin National Primate Research Center, Madison, Wisconsin, USA
| | - Helen Feltovich
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA; Maternal Fetal Medicine, Intermountain Healthcare, Provo, Utah, USA
| | - Timothy J Hall
- Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin, USA
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8
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Lam ACL, Pang SWA, Ahuja AT, Bhatia KSS. The influence of precompression on elasticity of thyroid nodules estimated by ultrasound shear wave elastography. Eur Radiol 2015; 26:2845-52. [DOI: 10.1007/s00330-015-4108-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 10/31/2015] [Accepted: 11/10/2015] [Indexed: 01/17/2023]
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9
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Peralta L, Rus G, Bochud N, Molina F. Assessing viscoelasticity of shear wave propagation in cervical tissue by multiscale computational simulation. J Biomech 2015; 48:1549-56. [DOI: 10.1016/j.jbiomech.2015.01.044] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 01/31/2015] [Indexed: 01/17/2023]
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10
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Omari EA, Varghese T, Kliewer MA, Harter J, Hartenbach EM. Dynamic and quasi-static mechanical testing for characterization of the viscoelastic properties of human uterine tissue. J Biomech 2015; 48:1730-6. [PMID: 26072212 DOI: 10.1016/j.jbiomech.2015.05.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/22/2015] [Accepted: 05/14/2015] [Indexed: 02/02/2023]
Abstract
Ultrasound elastography is envisioned as an optional modality to augment standard ultrasound B-mode imaging and is a promising technique to aid in detecting uterine masses which cause abnormal uterine bleeding in both pre- and post-menopausal women. In order to determine the effectiveness of strain imaging, mechanical testing to establish the elastic contrast between normal uterine tissue and stiffer masses such as leiomyomas (fibroids) and between softer pathologies such as uterine cancer and adenomyosis has to be performed. In this paper, we evaluate the stiffness of normal uterine tissue, leiomyomas, and endometrial cancers using a EnduraTEC ElectroForce (ELF) system. We quantify the viscoelastic characteristics of uterine tissue and associated pathologies globally by using two mechanical testing approaches, namely a dynamic and a quasi-static (ramp testing) approach. For dynamic testing, 21 samples obtained from 18 patients were tested. The testing frequencies were set to 1, 10, 20, and 30 Hz. We also report on stiffness variations with pre-compression from 1% to 6% for testing at 2%, 3%, and 4% strain amplitude. Our results show that human uterine tissue stiffness is both dependent on percent pre-compression and testing frequencies. For ramp testing, 20 samples obtained from 14 patients were used. A constant strain rate of 0.1% was applied and comparable results to dynamic testing were obtained. The mean modulus contrast at 2% amplitude between normal uterine tissue (the background) and leiomyomas was 2.29 and 2.17, and between the background and cancer was 0.47 and 0.39 for dynamic and ramp testing, respectively.
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Affiliation(s)
- Eenas A Omari
- Department of Medical Physics, The University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI 53705, United States; Department of Electrical and Computer Engineering, The University of Wisconsin-Madison, Madison, WI 53705, United States.
| | - Tomy Varghese
- Department of Medical Physics, The University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI 53705, United States; Department of Electrical and Computer Engineering, The University of Wisconsin-Madison, Madison, WI 53705, United States.
| | - Mark A Kliewer
- Department of Radiology, The University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI 53705, United States
| | - Josephine Harter
- Department of Pathology, The University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI 53705, United States
| | - Ellen M Hartenbach
- Department of Gynecologic-Oncology, The University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI 53705, United States
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11
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DeWall RJ, Bharat S, Varghese T, Hanson ME, Agni RM, Kliewer MA. Characterizing the compression-dependent viscoelastic properties of human hepatic pathologies using dynamic compression testing. Phys Med Biol 2012; 57:2273-86. [PMID: 22459948 DOI: 10.1088/0031-9155/57/8/2273] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Recent advances in elastography have provided several imaging modalities capable of quantifying the elasticity of tissue, an intrinsic tissue property. This information is useful for determining tumour margins and may also be useful for diagnosing specific tumour types. In this study, we used dynamic compression testing to quantify the viscoelastic properties of 16 human hepatic primary and secondary malignancies and their corresponding background tissue obtained following surgical resection. Two additional backgrounds were also tested. An analysis of the background tissue showed that F4-graded fibrotic liver tissue was significantly stiffer than F0-graded tissue, with a modulus contrast of 4:1. Steatotic liver tissue was slightly stiffer than normal liver tissue, but not significantly so. The tumour-to-background storage modulus contrast of hepatocellular carcinomas, a primary tumour, was approximately 1:1, and the contrast decreased with increasing fibrosis grade of the background tissue. Ramp testing showed that the background stiffness increased faster than the malignant tissue. Conversely, secondary tumours were typically much stiffer than the surrounding background, with a tumour-to-background contrast of 10:1 for colon metastases and 10:1 for cholangiocarcinomas. Ramp testing showed that colon metastases stiffened faster than their corresponding backgrounds. These data have provided insights into the mechanical properties of specific tumour types, which may prove beneficial as the use of quantitative stiffness imaging increases.
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Affiliation(s)
- Ryan J DeWall
- Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA.
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12
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Kiss MZ, Varghese T, Kliewer M. Exvivo ultrasound attenuation coefficient for human cervical and uterine tissue from 5 to 10 MHz. ULTRASONICS 2011; 51:467-71. [PMID: 21163508 PMCID: PMC3056396 DOI: 10.1016/j.ultras.2010.11.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2010] [Revised: 11/23/2010] [Accepted: 11/23/2010] [Indexed: 05/07/2023]
Abstract
Attenuation estimation and imaging in the cervix has been utilized to evaluate the onset of cervical ripening during pregnancy. This feature has also been utilized for the acoustic characterization of leiomyomas and myometrial tissue. In this paper, we present direct narrowband substitution measurement values of the variation in the ultrasonic attenuation coefficient in ex vivo human uterine and cervical tissue, in the 5-10 MHz frequency range. At 5 MHz, the attenuation coefficient values are similar for the different orientations of uterine tissue with values of 4.1-4.2 dB/cm, 5.1 dB/cm for the leiomyoma, and 6.3 dB/cm for the cervix. As the frequency increases, the attenuation coefficient values increase and are also spread out, with a value of approximately 12.6 dB/cm for the uterus (both parallel and perpendicular), 16.0 for the leiomyoma, and 26.8 dB/cm for the cervix at 10 MHz. The attenuation coefficient measured increases monotonically over the frequency range measured following a power law.
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Affiliation(s)
- Miklos Z. Kiss
- Applied Physics Laboratory, Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD 20723-6099
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53706, USA
| | - Tomy Varghese
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53706, USA
| | - M.A. Kliewer
- Department of Radiology, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI 53706, USA
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