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Torbati S, Daneshmehr A, Pouraliakbar H, Asgharian M, Ahmadi Tafti SH, Shum-Tim D, Heidari A. Personalized evaluation of the passive myocardium in ischemic cardiomyopathy via computational modeling using Bayesian optimization. Biomech Model Mechanobiol 2024:10.1007/s10237-024-01856-0. [PMID: 38954283 DOI: 10.1007/s10237-024-01856-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 04/28/2024] [Indexed: 07/04/2024]
Abstract
Biomechanics-based patient-specific modeling is a promising approach that has proved invaluable for its clinical potential to assess the adversities caused by ischemic heart disease (IHD). In the present study, we propose a framework to find the passive material properties of the myocardium and the unloaded shape of cardiac ventricles simultaneously in patients diagnosed with ischemic cardiomyopathy (ICM). This was achieved by minimizing the difference between the simulated and the target end-diastolic pressure-volume relationships (EDPVRs) using black-box Bayesian optimization, based on the finite element analysis (FEA). End-diastolic (ED) biventricular geometry and the location of the ischemia were determined from cardiac magnetic resonance (CMR) imaging. We employed our pipeline to model the cardiac ventricles of three patients aged between 57 and 66 years, with and without the inclusion of valves. An excellent agreement between the simulated and the target EDPVRs has been reached. Our results revealed that the incorporation of valvular springs typically leads to lower hyperelastic parameters for both healthy and ischemic myocardium, as well as a higher fiber Green strain in the viable regions compared to models without valvular stiffness. Furthermore, the addition of valve-related effects did not result in significant changes in myofiber stress after optimization. We concluded that more accurate results could be obtained when cardiac valves were considered in modeling ventricles. The present novel and practical methodology paves the way for developing digital twins of ischemic cardiac ventricles, providing a non-invasive assessment for designing optimal personalized therapies in precision medicine.
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Affiliation(s)
- Saeed Torbati
- Research Center for Advanced Technologies in Cardiovascular Medicine, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran
- School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Alireza Daneshmehr
- School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran
| | - Hamidreza Pouraliakbar
- Rajaie Cardiovascular, Medical, and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Masoud Asgharian
- Department of Mathematics and Statistics, McGill University, Montreal, QC, Canada
| | - Seyed Hossein Ahmadi Tafti
- Research Center for Advanced Technologies in Cardiovascular Medicine, Cardiovascular Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
- Department of Surgery, Tehran Heart Center, Tehran University of Medical Sciences, Tehran, Iran.
| | - Dominique Shum-Tim
- Division of Cardiac Surgery, Department of Surgery, McGill University, Montreal, QC, Canada
| | - Alireza Heidari
- Department of Mathematics and Statistics, McGill University, Montreal, QC, Canada.
- Department of Mechanical Engineering, McGill University, Montreal, QC, Canada.
- Department of Biomedical Engineering, McGill University, Montreal, QC, Canada.
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Ding CCA, Dokos S, Bakir AA, Zamberi NJ, Liew YM, Chan BT, Md Sari NA, Avolio A, Lim E. Simulating impaired left ventricular-arterial coupling in aging and disease: a systematic review. Biomed Eng Online 2024; 23:24. [PMID: 38388416 PMCID: PMC10885508 DOI: 10.1186/s12938-024-01206-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 01/11/2024] [Indexed: 02/24/2024] Open
Abstract
Aortic stenosis, hypertension, and left ventricular hypertrophy often coexist in the elderly, causing a detrimental mismatch in coupling between the heart and vasculature known as ventricular-vascular (VA) coupling. Impaired left VA coupling, a critical aspect of cardiovascular dysfunction in aging and disease, poses significant challenges for optimal cardiovascular performance. This systematic review aims to assess the impact of simulating and studying this coupling through computational models. By conducting a comprehensive analysis of 34 relevant articles obtained from esteemed databases such as Web of Science, Scopus, and PubMed until July 14, 2022, we explore various modeling techniques and simulation approaches employed to unravel the complex mechanisms underlying this impairment. Our review highlights the essential role of computational models in providing detailed insights beyond clinical observations, enabling a deeper understanding of the cardiovascular system. By elucidating the existing models of the heart (3D, 2D, and 0D), cardiac valves, and blood vessels (3D, 1D, and 0D), as well as discussing mechanical boundary conditions, model parameterization and validation, coupling approaches, computer resources and diverse applications, we establish a comprehensive overview of the field. The descriptions as well as the pros and cons on the choices of different dimensionality in heart, valve, and circulation are provided. Crucially, we emphasize the significance of evaluating heart-vessel interaction in pathological conditions and propose future research directions, such as the development of fully coupled personalized multidimensional models, integration of deep learning techniques, and comprehensive assessment of confounding effects on biomarkers.
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Affiliation(s)
- Corina Cheng Ai Ding
- Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia
- Graduate School of Biomedical Engineering, Faculty of Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Socrates Dokos
- Graduate School of Biomedical Engineering, Faculty of Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Azam Ahmad Bakir
- University of Southampton Malaysia Campus, 79200, Iskandar Puteri, Johor, Malaysia
| | - Nurul Jannah Zamberi
- Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia
- Graduate School of Biomedical Engineering, Faculty of Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Yih Miin Liew
- Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Bee Ting Chan
- Department of Mechanical, Materials and Manufacturing Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, 43500, Selangor, Malaysia
| | - Nor Ashikin Md Sari
- Department of Medicine, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia
| | - Alberto Avolio
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, NSW, 2109, Australia
| | - Einly Lim
- Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia.
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Karimi A, Razaghi R, D'costa SD, Torbati S, Ebrahimi S, Rahmati SM, Kelley MJ, Acott TS, Gong H. Implementing new computational methods for the study of JCT and SC inner wall basement membrane biomechanics and hydrodynamics. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 243:107909. [PMID: 37976613 PMCID: PMC10840991 DOI: 10.1016/j.cmpb.2023.107909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/28/2023] [Accepted: 10/30/2023] [Indexed: 11/19/2023]
Abstract
PURPOSE The conventional aqueous outflow pathway, which includes the trabecular meshwork (TM), juxtacanalicular tissue (JCT), and the inner wall endothelium of Schlemm's canal (SC), regulates intraocular pressure (IOP) by controlling the aqueous humor outflow resistance. Despite its importance, our understanding of the biomechanics and hydrodynamics within this region remains limited. Fluid-structure interaction (FSI) offers a way to estimate the biomechanical properties of the JCT and SC under various loading and boundary conditions, providing valuable insights that are beyond the reach of current imaging techniques. METHODS In this study, a normal human eye was fixed at a pressure of 7 mm Hg, and two radial wedges of the TM tissues, which included the SC inner wall basement membrane and JCT, were dissected, processed, and imaged using 3D serial block-face scanning electron microscopy (SBF-SEM). Four different sets of images were used to create 3D finite element (FE) models of the JCT and inner wall endothelial cells of SC with their basement membrane. The outer JCT portion was carefully removed as the outflow resistance is not in that region, leaving only the SCE inner wall and a few µm of the tissue, which does contain the resistance. An inverse iterative FE algorithm was then utilized to calculate the unloaded geometry of the JCT/SC complex at an aqueous humor pressure of 0 mm Hg. Then in the model, the intertrabecular spaces, pores, and giant vacuole contents were replaced by aqueous humor, and FSI was employed to pressurize the JCT/SC complex from 0 to 15 mm Hg. RESULTS In the JCT/SC complex, the shear stress of the aqueous humor is not evenly distributed. Areas proximal to the inner wall of SC experience larger stresses, reaching up to 10 Pa, while those closer to the JCT undergo lower stresses, approximately 4 Pa. Within this complex, giant vacuoles with or without I-pore behave differently. Those without I-pores experience a more significant strain, around 14%, compared to those with I-pores, where the strain is roughly 9%. CONCLUSIONS The distribution of aqueous humor wall shear stress is not uniform within the JCT/SC complex, which may contribute to our understanding of the underlying selective mechanisms in the pathway.
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Affiliation(s)
- Alireza Karimi
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States; Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR, United States.
| | - Reza Razaghi
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States
| | - Siddharth Daniel D'costa
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States
| | - Saeed Torbati
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States
| | - Sina Ebrahimi
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States.
| | | | - Mary J Kelley
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States; Department Integrative Biosciences, School of Dentistry, Oregon Health & Science University, Portland, OR, United States.
| | - Ted S Acott
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States; Department Chemical Physiology & Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, United States.
| | - Haiyan Gong
- Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States; Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, United States.
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Geronzi L, Bel-Brunon A, Martinez A, Rochette M, Sensale M, Bouchot O, Lalande A, Lin S, Valentini PP, Biancolini ME. Calibration of the Mechanical Boundary Conditions for a Patient-Specific Thoracic Aorta Model Including the Heart Motion Effect. IEEE Trans Biomed Eng 2023; 70:3248-3259. [PMID: 37390004 DOI: 10.1109/tbme.2023.3287680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2023]
Abstract
OBJECTIVE We propose a procedure for calibrating 4 parameters governing the mechanical boundary conditions (BCs) of a thoracic aorta (TA) model derived from one patient with ascending aortic aneurysm. The BCs reproduce the visco-elastic structural support provided by the soft tissue and the spine and allow for the inclusion of the heart motion effect. METHODS We first segment the TA from magnetic resonance imaging (MRI) angiography and derive the heart motion by tracking the aortic annulus from cine-MRI. A rigid-wall fluid-dynamic simulation is performed to derive the time-varying wall pressure field. We build the finite element model considering patient-specific material properties and imposing the derived pressure field and the motion at the annulus boundary. The calibration, which involves the zero-pressure state computation, is based on purely structural simulations. After obtaining the vessel boundaries from the cine-MRI sequences, an iterative procedure is performed to minimize the distance between them and the corresponding boundaries derived from the deformed structural model. A strongly-coupled fluid-structure interaction (FSI) analysis is finally performed with the tuned parameters and compared to the purely structural simulation. RESULTS AND CONCLUSION The calibration with structural simulations allows to reduce maximum and mean distances between image-derived and simulation-derived boundaries from 8.64 mm to 6.37 mm and from 2.24 mm to 1.83 mm, respectively. The maximum root mean square error between the deformed structural and FSI surface meshes is 0.19 mm. This procedure may prove crucial for increasing the model fidelity in replicating the real aortic root kinematics.
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Hucke L, Holder J, van Drongelen S, Stief F, Gámez AJ, Huß A, Wittek A. Influence of tension-band plates on the mechanical loading of the femoral growth plate during guided growth due to coronal plane deformities. Front Bioeng Biotechnol 2023; 11:1165963. [PMID: 37415789 PMCID: PMC10321528 DOI: 10.3389/fbioe.2023.1165963] [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: 02/14/2023] [Accepted: 06/07/2023] [Indexed: 07/08/2023] Open
Abstract
Introduction: Correction of knee malalignment by guided growth using a tension-band plate is a common therapy to prevent knee osteoarthritis among other things. This approach is based on the Hueter-Volkmann law stating that the length growth of bones is inhibited by compression and stimulated by tension. How the locally varying mechanical loading of the growth plate is influenced by the implant has not yet been investigated. This study combines load cases from the gait cycle with personalized geometry in order to investigate the mechanical influence of the tension-band plates. Methods: Personalized finite element models of four distal femoral epiphyses of three individuals, that had undergone guided growth, were generated. Load cases from the gait cycles and musculoskeletal modelling were simulated with and without implant. Morphological features of the growth plates were obtained from radiographs. 3D geometries were completed using non-individual Magnetic Resonance Images of age-matched individuals. Boundary conditions for the models were obtained from instrumented gait analyses. Results: The stress distribution in the growth plate was heterogenous and depended on the geometry. In the insertion region, the implants locally induced static stress and reduced the cyclic loading and unloading. Both factors that reduce the growth rate. On the contralateral side of the growth plate, increased tension stress was observed, which stimulates growth. Discussion: Personalized finite element models are able to estimate the changes of local static and cyclic loading of the growth plate induced by the implant. In future, this knowledge can help to better control growth modulation and avoid the return of the malalignment after the treatment. However, this requires models that are completely participant-specific in terms of load cases and 3D geometry.
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Affiliation(s)
- Lucie Hucke
- Peronalized Biomedical Engineering Laboratory, Frankfurt University of Applied Sciences, Frankfurt am Main, Germany
- Department of Mechanical Engineering and Industrial Design, School of Engineering, University of Cádiz, Cádiz, Spain
| | - Jana Holder
- Department of Orthopedics (Friedrichsheim), University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Stefan van Drongelen
- Department of Orthopedics (Friedrichsheim), University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt am Main, Germany
- Dr. Rolf M. Schwiete Research Unit for Osteoarthritis, Department of Orthopedics (Friedrichsheim), University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Felix Stief
- Department of Orthopedics (Friedrichsheim), University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt am Main, Germany
- Dr. Rolf M. Schwiete Research Unit for Osteoarthritis, Department of Orthopedics (Friedrichsheim), University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Antonio J. Gámez
- Department of Mechanical Engineering and Industrial Design, School of Engineering, University of Cádiz, Cádiz, Spain
| | - Armin Huß
- Peronalized Biomedical Engineering Laboratory, Frankfurt University of Applied Sciences, Frankfurt am Main, Germany
| | - Andreas Wittek
- Peronalized Biomedical Engineering Laboratory, Frankfurt University of Applied Sciences, Frankfurt am Main, Germany
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Arnold N, Scott J, Bush TR. A review of the characterizations of soft tissues used in human body modeling: Scope, limitations, and the path forward. J Tissue Viability 2023; 32:286-304. [PMID: 36878737 DOI: 10.1016/j.jtv.2023.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 02/06/2023] [Accepted: 02/10/2023] [Indexed: 02/27/2023]
Abstract
Soft tissue material properties are vital to human body models that evaluate interactions between the human body and its environment. Such models evaluate internal stress/strain responses in soft tissues to investigate issues like pressure injuries. Numerous constitutive models and parameters have been used to represent mechanical behavior of soft tissues in biomechanical models under quasi-static loading. However, researchers reported that generic material properties cannot accurately represent specific target populations due to large inter-individual variability. Two challenges that exist are experimental mechanical characterization and constitutive modeling of biological soft tissues and personalization of constitutive parameters using non-invasive, non-destructive bedside testing methods. It is imperative to understand the scope and appropriate applications for reported material properties. Thus, the goal of this paper was to compile studies from which soft tissue material properties were obtained and categorize them by source of tissue samples, methods used to quantify deformation, and material models used to describe tissues. The collected studies displayed wide ranges of material properties, and factors that affected the properties included whether tissue samples were in vivo or ex vivo, from humans or animals, the body region tested, body position during in vivo studies, deformation measurements, and material models used to describe tissues. Because of the factors that affected reported material properties, it is clear that much progress has been made in understanding soft tissue responses to loading, yet there is a need to broaden the scope of reported soft tissue material properties and better match reported properties to appropriate human body models.
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Affiliation(s)
- Nicole Arnold
- Department of Mechanical Engineering, Michigan State University, 428 S Shaw Lane, Rm. 2555 Engineering Building, East Lansing, MI, 48824-1226, USA
| | - Justin Scott
- Department of Mechanical Engineering, Michigan State University, 428 S Shaw Lane, Rm. 2555 Engineering Building, East Lansing, MI, 48824-1226, USA
| | - Tamara Reid Bush
- Department of Mechanical Engineering, Michigan State University, 428 S Shaw Lane, Rm. 2555 Engineering Building, East Lansing, MI, 48824-1226, USA.
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Nolte D, Bertoglio C. Inverse problems in blood flow modeling: A review. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3613. [PMID: 35526113 PMCID: PMC9541505 DOI: 10.1002/cnm.3613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 12/29/2021] [Accepted: 03/18/2022] [Indexed: 06/14/2023]
Abstract
Mathematical and computational modeling of the cardiovascular system is increasingly providing non-invasive alternatives to traditional invasive clinical procedures. Moreover, it has the potential for generating additional diagnostic markers. In blood flow computations, the personalization of spatially distributed (i.e., 3D) models is a key step which relies on the formulation and numerical solution of inverse problems using clinical data, typically medical images for measuring both anatomy and function of the vasculature. In the last years, the development and application of inverse methods has rapidly expanded most likely due to the increased availability of data in clinical centers and the growing interest of modelers and clinicians in collaborating. Therefore, this work aims to provide a wide and comparative overview of literature within the last decade. We review the current state of the art of inverse problems in blood flows, focusing on studies considering fully dimensional fluid and fluid-solid models. The relevant physical models and hemodynamic measurement techniques are introduced, followed by a survey of mathematical data assimilation approaches used to solve different kinds of inverse problems, namely state and parameter estimation. An exhaustive discussion of the literature of the last decade is presented, structured by types of problems, models and available data.
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Affiliation(s)
- David Nolte
- Bernoulli InstituteUniversity of GroningenGroningenThe Netherlands
- Center for Mathematical ModelingUniversidad de ChileSantiagoChile
- Department of Fluid DynamicsTechnische Universität BerlinBerlinGermany
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Marx L, Niestrawska JA, Gsell MA, Caforio F, Plank G, Augustin CM. Robust and efficient fixed-point algorithm for the inverse elastostatic problem to identify myocardial passive material parameters and the unloaded reference configuration. JOURNAL OF COMPUTATIONAL PHYSICS 2022; 463:111266. [PMID: 35662800 PMCID: PMC7612790 DOI: 10.1016/j.jcp.2022.111266] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Image-based computational models of the heart represent a powerful tool to shed new light on the mechanisms underlying physiological and pathological conditions in cardiac function and to improve diagnosis and therapy planning. However, in order to enable the clinical translation of such models, it is crucial to develop personalized models that are able to reproduce the physiological reality of a given patient. There have been numerous contributions in experimental and computational biomechanics to characterize the passive behavior of the myocardium. However, most of these studies suffer from severe limitations and are not applicable to high-resolution geometries. In this work, we present a novel methodology to perform an automated identification of in vivo properties of passive cardiac biomechanics. The highly-efficient algorithm fits material parameters against the shape of a patient-specific approximation of the end-diastolic pressure-volume relation (EDPVR). Simultaneously, an unloaded reference configuration is generated, where a novel line search strategy to improve convergence and robustness is implemented. Only clinical image data or previously generated meshes at one time point during diastole and one measured data point of the EDPVR are required as an input. The proposed method can be straightforwardly coupled to existing finite element (FE) software packages and is applicable to different constitutive laws and FE formulations. Sensitivity analysis demonstrates that the algorithm is robust with respect to initial input parameters.
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Affiliation(s)
- Laura Marx
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging - Division of Biophysics, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Justyna A. Niestrawska
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging - Division of Biophysics, Medical University of Graz, Graz, Austria
| | - Matthias A.F. Gsell
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging - Division of Biophysics, Medical University of Graz, Graz, Austria
| | - Federica Caforio
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging - Division of Biophysics, Medical University of Graz, Graz, Austria
- Institute of Mathematics and Scientific Computing, University of Graz, Graz, Austria
| | - Gernot Plank
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging - Division of Biophysics, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Christoph M. Augustin
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging - Division of Biophysics, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
- Corresponding author at: Gottfried Schatz Research Center: Division of Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/D04, 8010 Graz, Austria. (C.M.Augustin)
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9
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Karabelas E, Gsell MA, Haase G, Plank G, Augustin CM. An accurate, robust, and efficient finite element framework with applications to anisotropic, nearly and fully incompressible elasticity. COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2022; 394:114887. [PMID: 35432634 PMCID: PMC7612621 DOI: 10.1016/j.cma.2022.114887] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Fiber-reinforced soft biological tissues are typically modeled as hyperelastic, anisotropic, and nearly incompressible materials. To enforce incompressibility a multiplicative split of the deformation gradient into a volumetric and an isochoric part is a very common approach. However, the finite element analysis of such problems often suffers from severe volumetric locking effects and numerical instabilities. In this paper, we present novel methods to overcome volumetric locking phenomena for using stabilized P1-P1 elements. We introduce different stabilization techniques and demonstrate the high robustness and computational efficiency of the chosen methods. In two benchmark problems from the literature as well as an advanced application to cardiac electromechanics, we compare the approach to standard linear elements and show the accuracy and versatility of the methods to simulate anisotropic, nearly and fully incompressible materials. We demonstrate the potential of this numerical framework to accelerate accurate simulations of biological tissues to the extent of enabling patient-specific parameterization studies, where numerous forward simulations are required.
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Affiliation(s)
- Elias Karabelas
- Institute for Mathematics and Scientific Computing, Karl-Franzens-University Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Matthias A.F. Gsell
- Gottfried Schatz Research Center: Division of Biophysics, Medical University of Graz, Graz, Austria
| | - Gundolf Haase
- Institute for Mathematics and Scientific Computing, Karl-Franzens-University Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Gernot Plank
- Gottfried Schatz Research Center: Division of Biophysics, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Christoph M. Augustin
- Gottfried Schatz Research Center: Division of Biophysics, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
- Correspondence to: Gottfried Schatz Research Center: Division of Biophysics, Medical University of Graz, Neue Stiftingtalstrasse 6/IV, Graz 8010, Austria. (C.M. Augustin)
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10
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A quasi-static poromechanical model of the lungs. Biomech Model Mechanobiol 2022; 21:527-551. [DOI: 10.1007/s10237-021-01547-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 12/09/2021] [Indexed: 11/02/2022]
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11
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Huang Y, Wang S, Luo T, Du MHF, Sun C, Sadat U, Schönlieb CB, Gillard JH, Zhang J, Teng Z. Estimation of the zero-pressure computational start shape of atherosclerotic plaques: Improving the backward displacement method with deformation gradient tensor. J Biomech 2022; 131:110910. [PMID: 34954525 DOI: 10.1016/j.jbiomech.2021.110910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 10/16/2021] [Accepted: 12/10/2021] [Indexed: 01/06/2023]
Abstract
Advances in medical imaging have enabled patient-specific biomechanical modelling of arterial lesions such as atherosclerosis and aneurysm. Geometry acquired from in-vivo imaging is already pressurized and a zero-pressure computational start shape needs to be identified. The backward displacement algorithm was proposed to solve this inverse problem, utilizing fixed-point iterations to gradually approach the start shape. However, classical fixed-point implementations were reported with suboptimal convergence properties under large deformations. In this paper, a dynamic learning rate guided by the deformation gradient tensor was introduced to control the geometry update. The effectiveness of this new algorithm was demonstrated for both idealized and patient-specific models. The proposed algorithm led to faster convergence by accelerating the initial steps and helped to avoid the non-convergence in large-deformation problems.
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Affiliation(s)
- Yuan Huang
- EPSRC Cambridge Mathematics of Information in Healthcare, University of Cambridge, Cambridge, UK; Department of Radiology, University of Cambridge, Cambridge, UK
| | - Shuo Wang
- Department of Radiology, University of Cambridge, Cambridge, UK; Shanghai Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention, Fudan University, Shanghai, China; Digital Medical Research Center, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Tao Luo
- Department of Engineering, University of Cambridge, Cambridge, UK
| | - Michael Hong-Fei Du
- Department of Radiology, University of Cambridge, Cambridge, UK; John Farman Intensive Care Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Chang Sun
- Department of Radiology, University of Cambridge, Cambridge, UK
| | - Umar Sadat
- Cambridge Vascular Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Carola-Bibiane Schönlieb
- EPSRC Cambridge Mathematics of Information in Healthcare, University of Cambridge, Cambridge, UK; Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, UK
| | | | - Jianjun Zhang
- Department of Radiology, Zhejiang Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhongzhao Teng
- Department of Radiology, University of Cambridge, Cambridge, UK; Nanjing Jingsan Medical Science and Technology, Ltd, Jiangsu, China.
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12
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Fan Y, Coll-Font J, van den Boomen M, Kim JH, Chen S, Eder RA, Roche ET, Nguyen CT. Characterization of Exercise-Induced Myocardium Growth Using Finite Element Modeling and Bayesian Optimization. Front Physiol 2021; 12:694940. [PMID: 34434115 PMCID: PMC8381603 DOI: 10.3389/fphys.2021.694940] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 07/19/2021] [Indexed: 02/03/2023] Open
Abstract
Cardiomyocyte growth can occur in both physiological (exercised-induced) and pathological (e.g., volume overload and pressure overload) conditions leading to left ventricular (LV) hypertrophy. Studies using animal models and histology have demonstrated the growth and remodeling process at the organ level and tissue-cellular level, respectively. However, the driving factors of growth and the mechanistic link between organ, tissue, and cellular growth remains poorly understood. Computational models have the potential to bridge this gap by using constitutive models that describe the growth and remodeling process of the myocardium coupled with finite element (FE) analysis to model the biomechanics of the heart at the organ level. Using subject-specific imaging data of the LV geometry at two different time points, an FE model can be created with the inverse method to characterize the growth parameters of each subject. In this study, we developed a framework that takes in vivo cardiac magnetic resonance (CMR) imaging data of exercised porcine model and uses FE and Bayesian optimization to characterize myocardium growth in the transverse and longitudinal directions. The efficacy of this framework was demonstrated by successfully predicting growth parameters of 18 synthetic LV targeted masks which were generated from three LV porcine geometries. The framework was further used to characterize growth parameters in 4 swine subjects that had been exercised. The study suggested that exercise-induced growth in swine is prone to longitudinal cardiomyocyte growth (58.0 ± 19.6% after 6 weeks and 79.3 ± 15.6% after 12 weeks) compared to transverse growth (4.0 ± 8.0% after 6 weeks and 7.8 ± 9.4% after 12 weeks). This framework can be used to characterize myocardial growth in different phenotypes of LV hypertrophy and can be incorporated with other growth constitutive models to study different hypothetical growth mechanisms.
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Affiliation(s)
- Yiling Fan
- Cardiovascular Bioengineering and Imaging Laboratory, Cardiology Division, Massachusetts General Hospital, Charlestown, MA, United States,Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Jaume Coll-Font
- Cardiovascular Bioengineering and Imaging Laboratory, Cardiology Division, Massachusetts General Hospital, Charlestown, MA, United States,Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States,Harvard Medical School, Boston, MA, United States
| | - Maaike van den Boomen
- Cardiovascular Bioengineering and Imaging Laboratory, Cardiology Division, Massachusetts General Hospital, Charlestown, MA, United States,Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States,Harvard Medical School, Boston, MA, United States
| | - Joan H. Kim
- Cardiovascular Bioengineering and Imaging Laboratory, Cardiology Division, Massachusetts General Hospital, Charlestown, MA, United States
| | - Shi Chen
- Cardiovascular Bioengineering and Imaging Laboratory, Cardiology Division, Massachusetts General Hospital, Charlestown, MA, United States
| | - Robert Alan Eder
- Cardiovascular Bioengineering and Imaging Laboratory, Cardiology Division, Massachusetts General Hospital, Charlestown, MA, United States
| | - Ellen T. Roche
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, United States,Harvard Medical School, Boston, MA, United States,*Correspondence: Ellen T. Roche,
| | - Christopher T. Nguyen
- Cardiovascular Bioengineering and Imaging Laboratory, Cardiology Division, Massachusetts General Hospital, Charlestown, MA, United States,Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, United States,Harvard Medical School, Boston, MA, United States,Christopher T. Nguyen,
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13
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Lee T, Holland MA, Weickenmeier J, Gosain AK, Tepole AB. The Geometry of Incompatibility in Growing Soft Tissues: Theory and Numerical Characterization. JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS 2021; 146:104177. [PMID: 34054143 PMCID: PMC8153650 DOI: 10.1016/j.jmps.2020.104177] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Tissues in vivo are not stress-free. As we grow, our tissues adapt to different physiological and disease conditions through growth and remodeling. This adaptation occurs at the microscopic scale, where cells control the microstructure of their immediate extracellular environment to achieve homeostasis. The local and heterogeneous nature of this process is the source of residual stresses. At the macroscopic scale, growth and remodeling can be accurately captured with the finite volume growth framework within continuum mechanics, which is akin to plasticity. The multiplicative split of the deformation gradient into growth and elastic contributions brings about the notion of incompatibility as a plausible description for the origin of residual stress. Here we define the geometric features that characterize incompatibility in biological materials. We introduce the geometric incompatibility tensor for different growth types, showing that the constraints associated with growth lead to specific patterns of the incompatibility metrics. To numerically investigate the distribution of incompatibility measures, we implement the analysis within a finite element framework. Simple, illustrative examples are shown first to explain the main concepts. Then, numerical characterization of incompatibility and residual stress is performed on three biomedical applications: brain atrophy, skin expansion, and cortical folding. Our analysis provides new insights into the role of growth in the development of tissue defects and residual stresses. Thus, we anticipate that our work will further motivate additional research to characterize residual stresses in living tissue and their role in development, disease, and clinical intervention.
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Affiliation(s)
- Taeksang Lee
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Maria A Holland
- Aerospace & Mechanical Engineering, University of Notre Dame, Notre Dame, IN, USA
| | - Johannes Weickenmeier
- Department of Mechanical Engineering, Stevens Institute of Technology, Hoboken, NJ, USA
| | - Arun K Gosain
- Lurie Children Hospital, Northwestern University, Chicago, IL, USA
| | - Adrian Buganza Tepole
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
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14
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Sugerman GP, Parekh SH, Rausch MK. Nonlinear, dissipative phenomena in whole blood clot mechanics. SOFT MATTER 2020; 16:9908-9916. [PMID: 33029598 DOI: 10.1039/d0sm01317j] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
When a thrombus breaks off and embolizes it can occlude vital vessels such as those of the heart, lung, or brain. These thromboembolic conditions are responsible for 1 in 4 deaths worldwide. Thrombus resistance to embolization is driven by its intrinsic fracture toughness as well as other, non-surface-creating dissipative mechanisms. In our current work, we identify and quantify these latter mechanisms toward future studies that aim to delineate fracture from other forms of dissipation. To this end, we use an in vitro thrombus mimic system to produce whole blood clots and explore their dissipative mechanics under simple uniaxial extension, cyclic loading, and stress-relaxation. We found that whole blood clots exhibit Mullins-like effect, hysteresis, permanent set, strain-rate dependence, and nonlinear stress-relaxation. Interestingly, we found that performing these tests under dry or submerged conditions did not change our results. However, performing these tests under room temperature or body temperature conditions yielded differences. Importantly, because we use venous blood our work is most closely related to venous in vivo blood clots. Overall, we have demonstrated that whole blood clots show several dissipative phenomena - similarly to hydrogels - that will be critical to our understanding of thrombus embolization.
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Affiliation(s)
- Gabriella P Sugerman
- Department of Biomedical Engineering, University of Texas at Austin, 107 West Dean Keaton, Austin, TX 78712, USA.
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15
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Sajjadinia SS, Carpentieri B, Holzapfel GA. A backward pre-stressing algorithm for efficient finite element implementation of in vivo material and geometrical parameters into fibril-reinforced mixture models of articular cartilage. J Mech Behav Biomed Mater 2020; 114:104203. [PMID: 33234496 DOI: 10.1016/j.jmbbm.2020.104203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 11/06/2020] [Accepted: 11/09/2020] [Indexed: 10/23/2022]
Abstract
Classical continuum mechanics has been widely used for implementation of the material models of articular cartilage (AC) mainly with the aid of the finite element (FE) method, which, in many cases, considers the stress-free configuration as the initial configuration. On the contrary, the AC experimental tests typically begin with the pre-stressed state of both material and geometrical properties. Indeed, imposing the initial pre-stress onto AC models with the in vivo values as the initial state would result in nonphysiologically expansion of the FE mesh due to the soft nature of AC. This change in the model configuration can also affect the material behavior kinematically in the mixture models of cartilage due to the intrinsic compressibility of the tissue. Although several different fixed-point backward algorithms, as the most straightforward pre-stressing methods, have already been developed to incorporate these initial conditions into FE models iteratively, such methods focused merely on the geometrical parameters, and they omitted the material variations of the anisotropic mixture models of AC. To address this issue, we propose an efficient algorithm generalizing the backward schemes to restore stress-free conditions by optimizing both the involving variables, and we hypothesize that it can affect the results considerably. To this end, a comparative simulation was implemented on an advanced and validated multiphasic model by the new and conventional algorithms. The results are in support of the hypothesis, as in our illustrative general AC model, the material parameters experienced a maximum error of 16% comparing to the initial in vivo data when the older algorithm was employed, and it led to a maximum variation of 44% in the recorded stresses comparing to the results of the new method. We conclude that our methodology enhanced the model fidelity, and it is applicable in most of the existing FE solvers for future mixture studies with accurate stress distributions.
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Affiliation(s)
| | - Bruno Carpentieri
- Faculty of Computer Science, Free University of Bozen-Bolzano, Bozen-Bolzano, 39100, Italy.
| | - Gerhard A Holzapfel
- Institute of Biomechanics, Graz University of Technology, Stremayrgasse 16/2, Graz, 8010, Austria; Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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16
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Nama N, Aguirre M, Humphrey JD, Figueroa CA. A nonlinear rotation-free shell formulation with prestressing for vascular biomechanics. Sci Rep 2020; 10:17528. [PMID: 33067508 PMCID: PMC7567841 DOI: 10.1038/s41598-020-74277-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/28/2020] [Indexed: 02/01/2023] Open
Abstract
We implement a nonlinear rotation-free shell formulation capable of handling large deformations for applications in vascular biomechanics. The formulation employs a previously reported shell element that calculates both the membrane and bending behavior via displacement degrees of freedom for a triangular element. The thickness stretch is statically condensed to enforce vessel wall incompressibility via a plane stress condition. Consequently, the formulation allows incorporation of appropriate 3D constitutive material models. We also incorporate external tissue support conditions to model the effect of surrounding tissue. We present theoretical and variational details of the formulation and verify our implementation against axisymmetric results and literature data. We also adapt a previously reported prestress methodology to identify the unloaded configuration corresponding to the medically imaged in vivo vessel geometry. We verify the prestress methodology in an idealized bifurcation model and demonstrate the significance of including prestress. Lastly, we demonstrate the robustness of our formulation via its application to mouse-specific models of arterial mechanics using an experimentally informed four-fiber constitutive model.
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Affiliation(s)
- Nitesh Nama
- grid.214458.e0000000086837370Department of Surgery, University of Michigan, Ann Arbor, MI USA
| | - Miquel Aguirre
- grid.6279.a0000 0001 2158 1682Mines Saint-Étienne, Univ Lyon, Univ Jean Monnet, INSERM, U 1059 Sainbiose, Centre CIS, 42023 Saint-Étienne, France
| | - Jay D. Humphrey
- grid.47100.320000000419368710Department of Biomedical Engineering, Yale University, New Haven, CT USA
| | - C. Alberto Figueroa
- grid.214458.e0000000086837370Department of Surgery, University of Michigan, Ann Arbor, MI USA ,grid.214458.e0000000086837370Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI USA
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17
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Jazwiec T, Malinowski MJ, Ferguson H, Parker J, Mathur M, Rausch MK, Timek TA. Tricuspid Valve Anterior Leaflet Strains in Ovine Functional Tricuspid Regurgitation. Semin Thorac Cardiovasc Surg 2020; 33:356-364. [PMID: 32977016 DOI: 10.1053/j.semtcvs.2020.09.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 09/08/2020] [Indexed: 01/31/2023]
Abstract
Functional tricuspid regurgitation (FTR) is thought to arise due to annular dilation and alteration of right ventricular (RV) geometry in the presence of normal leaflets, yet mitral leaflets have been shown to remodel significantly in functional mitral regurgitation. We set out to evaluate tricuspid valve anterior leaflet deformations in ovine FTR. Eleven animals (FTR group) underwent implantation of a pacemaker with high rate pacing to induce biventricular dysfunction and at least moderate TR. Subsequently, both FTR (n = 11) and Control (n = 12) animals underwent implantation of 6 sonomicrometry crystals around the tricuspid annulus, 4 on the anterior leaflet, and 14 on RV epicardium. Tricuspid valve geometry and anterior leaflet strains were calculated from crystal coordinates. Left ventricular ejection fraction and RV fractional area change were significantly lower in FTR animals versus Control. Tricuspid annular area, septo-lateral diameter, RV pressures were all significantly greater in the FTR group. Mean TR grade (+0-3) was 0.7 ± 0.5 in Control and 2.4 ± 0.5 in FTR (P = < 0.001). The anterior leaflet area and length increased significantly. Global radial leaflet strain was significantly lower in FTR mostly driven by decreased free edge leaflet strain. Global circumferential anterior leaflet strain was also significantly lower in FTR with more remarkable reduction in the belly region. Rapid ventricular pacing in sheep resulted in a clinically pertinent model of RV and annular dilation with FTR and leaflet enlargement. Both circumferential and radial anterior leaflet strains were significantly reduced with FTR. Functional TR may be associated with alteration of leaflet mechanical properties.
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Affiliation(s)
- Tomasz Jazwiec
- Division of Cardiothoracic Surgery, Spectrum Health, Grand Rapids, Michigan; Department of Cardiac, Vascular and Endovascular Surgery and Transplantology, Medical University of Silesia in Katowice, Silesian Centre for Heart Diseases, Zabrze, Poland
| | - Marcin J Malinowski
- Division of Cardiothoracic Surgery, Spectrum Health, Grand Rapids, Michigan; Department of Cardiac Surgery, Medical University of Silesia, School of Medicine in Katowice, Katowice, Poland
| | - Haley Ferguson
- Division of Cardiothoracic Surgery, Spectrum Health, Grand Rapids, Michigan
| | - Jessica Parker
- Research Department, Spectrum Health, Grand Rapids, Michigan
| | - Mrudang Mathur
- Department of Mechanical Engineering, University of Texas at Austin, Austin, Texas
| | - Manuel K Rausch
- Department of Aerospace Engineering & Engineering Mechanics, Department of Biomedical Engineering, Oden Institute for Computational Engineering and Science, University of Texas at Austin, Austin, Texas
| | - Tomasz A Timek
- Division of Cardiothoracic Surgery, Spectrum Health, Grand Rapids, Michigan.
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18
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Wisneski AD, Wang Y, Deuse T, Hill AC, Pasta S, Sack KL, Yao J, Guccione JM. Impact of Aortic Stenosis on Myofiber Stress: Translational Application of Left Ventricle-Aortic Coupling Simulation. Front Physiol 2020; 11:574211. [PMID: 33013489 PMCID: PMC7506067 DOI: 10.3389/fphys.2020.574211] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 08/19/2020] [Indexed: 12/19/2022] Open
Abstract
The severity of aortic stenosis (AS) has traditionally been graded by measuring hemodynamic parameters of transvalvular pressure gradient, ejection jet velocity, or estimating valve orifice area. Recent research has highlighted limitations of these criteria at effectively grading AS in presence of left ventricle (LV) dysfunction. We hypothesized that simulations coupling the aorta and LV could provide meaningful insight into myocardial biomechanical derangements that accompany AS. A realistic finite element model of the human heart with a coupled lumped-parameter circulatory system was used to simulate AS. Finite element analysis was performed with Abaqus FEA. An anisotropic hyperelastic model was assigned to LV passive properties, and a time-varying elastance function governed the LV active response. Global LV myofiber peak systolic stress (mean ± standard deviation) was 9.31 ± 10.33 kPa at baseline, 13.13 ± 10.29 kPa for moderate AS, and 16.18 ± 10.59 kPa for severe AS. Mean LV myofiber peak systolic strains were −22.40 ± 8.73%, −22.24 ± 8.91%, and −21.97 ± 9.18%, respectively. Stress was significantly elevated compared to baseline for moderate (p < 0.01) and severe AS (p < 0.001), and when compared to each other (p < 0.01). Ventricular regions that experienced the greatest systolic stress were (severe AS vs. baseline) basal inferior (39.87 vs. 30.02 kPa; p < 0.01), mid-anteroseptal (32.29 vs. 24.79 kPa; p < 0.001), and apex (27.99 vs. 23.52 kPa; p < 0.001). This data serves as a reference for future studies that will incorporate patient-specific ventricular geometries and material parameters, aiming to correlate LV biomechanics to AS severity.
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Affiliation(s)
- Andrew D Wisneski
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Yunjie Wang
- Thornton Tomassetti Lifesciences Division, Santa Clara, CA, United States
| | - Tobias Deuse
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Arthur C Hill
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Salvatore Pasta
- Department of Engineering, Universita degli Studi di Palermo, Palermo, Italy
| | - Kevin L Sack
- Cardiovascular Research Division, Medtronic Inc., Minneapolis, MN, United States
| | - Jiang Yao
- Dassault Systèmes Simulia, Johnston, RI, United States
| | - Julius M Guccione
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
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19
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LEACH JOSEPHR, ZHU CHENGCHENG, SALONER DAVID, HOPE MICHAELD. COMPARISON OF TWO METHODS FOR ESTIMATING THE UNLOADED STATE FOR ABDOMINAL AORTIC ANEURYSM STRESS CALCULATIONS. J MECH MED BIOL 2019. [DOI: 10.1142/s0219519419500155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Biomechanical analyses can be used to better understand the rupture risk of abdominal aortic aneurysms (AAAs) on a patient-specific basis using vascular geometries obtained from medical imaging. Methodologies of varying complexity are used to estimate the unloaded state of the imaged vessel to provide a reference configuration for finite element simulations. In this work, we compare the implementation and results of two of these methods, one based on geometric scaling and the other using an iterative determination of unloaded vessel geometry. We find that the two methods result in significantly different stress predictions, and that the iterative method offers superior geometric accuracy. Our findings lend context to the variation in finite element results presented in the AAA stress analysis literature.
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Affiliation(s)
- JOSEPH R. LEACH
- Department of Radiology and Biomedical Imaging, University of California, 505 Parnassus Avenue, M-391 San Francisco, CA 94143-0628, USA
| | - CHENGCHENG ZHU
- Department of Radiology and Biomedical Imaging, University of California, 505 Parnassus Avenue, M-391 San Francisco, CA 94143-0628, USA
| | - DAVID SALONER
- Department of Radiology and Biomedical Imaging, University of California, 505 Parnassus Avenue, M-391 San Francisco, CA 94143-0628, USA
- Department of Radiology, Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA
| | - MICHAEL D. HOPE
- Department of Radiology and Biomedical Imaging, University of California, 505 Parnassus Avenue, M-391 San Francisco, CA 94143-0628, USA
- Department of Radiology, Veterans Affairs Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA
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20
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Mathur M, Jazwiec T, Meador WD, Malinowski M, Goehler M, Ferguson H, Timek TA, Rausch MK. Tricuspid valve leaflet strains in the beating ovine heart. Biomech Model Mechanobiol 2019; 18:1351-1361. [PMID: 30980211 DOI: 10.1007/s10237-019-01148-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/03/2019] [Indexed: 12/25/2022]
Abstract
The tricuspid leaflets coapt during systole to facilitate proper valve function and, thus, ensure efficient transport of deoxygenated blood to the lungs. Between their open state and closed state, the leaflets undergo large deformations. Quantification of these deformations is important for our basic scientific understanding of tricuspid valve function and for diagnostic or prognostic purposes. To date, tricuspid valve leaflet strains have never been directly quantified in vivo. To fill this gap in our knowledge, we implanted four sonomicrometry crystals per tricuspid leaflet and six crystals along the tricuspid annulus in a total of five sheep. In the beating ovine hearts, we recorded crystal coordinates alongside hemodynamic data. Once recorded, we used a finite strain kinematic framework to compute the temporal evolutions of area strain, radial strain, and circumferential strain for each leaflet. We found that leaflet strains were larger in the anterior leaflet than the posterior and septal leaflets. Additionally, we found that radial strains were larger than circumferential strains. Area strains were as large as 97% in the anterior leaflet, 31% in the posterior leaflet, and 31% in the septal leaflet. These data suggest that tricuspid valve leaflet strains are significantly larger than those in the mitral valve. Should our findings be confirmed they could suggest either that the mechanobiological equilibrium of tricuspid valve resident cells is different than that of mitral valve resident cells or that the mechanotransductive apparatus between the two varies. Either phenomenon may have important implications for the development of tricuspid valve-specific surgical techniques and medical devices.
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Affiliation(s)
- M Mathur
- Department of Mechanical Engineering, University of Texas at Austin, Austin, TX, USA
| | - T Jazwiec
- Division of Cardiothoracic Surgery, Spectrum Health, Grand Rapids, MI, USA
- Department of Cardiac, Vascular and Endovascular Surgery and Transplantology, Medical University of Silesia in Katowice, Silesian Centre for Heart Diseases, Zabrze, Poland
| | - W D Meador
- Department of Biomedical Engineering, University of Texas at Austin, 2501 Speedway, Room 7.620, Austin, TX, 78712, USA
| | - M Malinowski
- Division of Cardiothoracic Surgery, Spectrum Health, Grand Rapids, MI, USA
- Department of Cardiac Surgery, School of Medicine in Katowice, Medical University of Silesia, Katowice, Poland
| | - M Goehler
- Division of Cardiothoracic Surgery, Spectrum Health, Grand Rapids, MI, USA
| | - H Ferguson
- Division of Cardiothoracic Surgery, Spectrum Health, Grand Rapids, MI, USA
| | - T A Timek
- Division of Cardiothoracic Surgery, Spectrum Health, Grand Rapids, MI, USA
| | - M K Rausch
- Department of Biomedical Engineering, University of Texas at Austin, 2501 Speedway, Room 7.620, Austin, TX, 78712, USA.
- Department of Aerospace Engineering and Engineering Mechanics, University of Texas at Austin, Austin, TX, USA.
- The Institute for Computational Engineering and Sciences, University of Texas at Austin, Austin, TX, USA.
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21
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Meador WD, Malinowski M, Jazwiec T, Goehler M, Quay N, Timek TA, Rausch MK. A fiduciary marker-based framework to assess heterogeneity and anisotropy of right ventricular epicardial strains in the beating ovine heart. J Biomech 2018; 80:179-185. [PMID: 30292534 DOI: 10.1016/j.jbiomech.2018.08.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 08/30/2018] [Accepted: 08/31/2018] [Indexed: 11/30/2022]
Abstract
Quantifying ventricular deformation in health and disease is critical to our understanding of normal heart function, heart disease mechanisms, and the effect of medical treatments. Imaging modalities have been developed that can measure ventricular deformation non-invasively. However, because of the small thickness, complex shape, and anatomic position of the right ventricle, using these technologies to determine its deformation remains challenging. Here we develop a first fiduciary marker-based method to assess heterogeneity and anisotropy of right ventricular epicardial strain across the entire free wall. To this end, we combine a high-density array of sonomicrometry crystals implanted across the entire right ventricular epicardial surface with a subdivision surface algorithm and a large deformation kinematics framework. We demonstrate our approach on four beating ovine hearts and present a preliminary regional analysis of circumferential, longitudinal, and areal strain. Moreover, we illustrate maps of the same strains across the entire right ventricular epicardial surface to highlight their spatial heterogeneity and anisotropy. We observe in these animals that RV epicardial strains vary throughout the cardiac cycle, are heterogeneous across the RV free wall, and are anisotropic with larger compressive strains, i.e., contraction, in the longitudinal direction than in the circumferential direction. Average peak compressive strains vary by region between -3.34% and -8.29% in circumferential direction, and -4.02% and -10.57% in longitudinal direction. In summary, we introduce an experimental framework that will allow us to study disease- and device-induced deformations, and long-term consequences of these deformations, including heterogeneous and anisotropic effects.
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Affiliation(s)
- William D Meador
- Department of Aerospace Engineering and Engineering Mechanics, University of Texas at Austin, TX, USA; Department of Biomedical Engineering, University of Texas at Austin, TX, USA
| | - Marcin Malinowski
- Meijer Heart and Vascular Institute at Spectrum Health, Michigan, MI, USA; Department of Cardiac Surgery, Medical University of Silesia, Katowice, Poland
| | - Tomasz Jazwiec
- Meijer Heart and Vascular Institute at Spectrum Health, Michigan, MI, USA
| | - Matthew Goehler
- Meijer Heart and Vascular Institute at Spectrum Health, Michigan, MI, USA
| | - Nathan Quay
- Meijer Heart and Vascular Institute at Spectrum Health, Michigan, MI, USA
| | - Tomasz A Timek
- Meijer Heart and Vascular Institute at Spectrum Health, Michigan, MI, USA
| | - Manuel K Rausch
- Department of Aerospace Engineering and Engineering Mechanics, University of Texas at Austin, TX, USA; Department of Biomedical Engineering, University of Texas at Austin, TX, USA; Institute for Computational Engineering and Sciences, University of Texas at Austin, TX, USA.
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22
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A modular inverse elastostatics approach to resolve the pressure-induced stress state for in vivo imaging based cardiovascular modeling. J Mech Behav Biomed Mater 2018; 85:124-133. [DOI: 10.1016/j.jmbbm.2018.05.032] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/28/2018] [Accepted: 05/22/2018] [Indexed: 01/18/2023]
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23
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Finsberg H, Xi C, Tan JL, Zhong L, Genet M, Sundnes J, Lee LC, Wall ST. Efficient estimation of personalized biventricular mechanical function employing gradient-based optimization. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e2982. [PMID: 29521015 PMCID: PMC6043386 DOI: 10.1002/cnm.2982] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 02/16/2018] [Accepted: 03/03/2018] [Indexed: 05/26/2023]
Abstract
Individually personalized computational models of heart mechanics can be used to estimate important physiological and clinically-relevant quantities that are difficult, if not impossible, to directly measure in the beating heart. Here, we present a novel and efficient framework for creating patient-specific biventricular models using a gradient-based data assimilation method for evaluating regional myocardial contractility and estimating myofiber stress. These simulations can be performed on a regular laptop in less than 2 h and produce excellent fit between measured and simulated volume and strain data through the entire cardiac cycle. By applying the framework using data obtained from 3 healthy human biventricles, we extracted clinically important quantities as well as explored the role of fiber angles on heart function. Our results show that steep fiber angles at the endocardium and epicardium are required to produce simulated motion compatible with measured strain and volume data. We also find that the contraction and subsequent systolic stresses in the right ventricle are significantly lower than that in the left ventricle. Variability of the estimated quantities with respect to both patient data and modeling choices are also found to be low. Because of its high efficiency, this framework may be applicable to modeling of patient specific cardiac mechanics for diagnostic purposes.
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Affiliation(s)
- Henrik Finsberg
- Simula Research Laboratory1325LysakerNorway
- Center for Cardiological InnovationSongsvannsveien 90372OsloNorway
- Department of InformaticsUniversity of OsloP.O. Box 1080, Blindern0316 OsloNorway
| | - Ce Xi
- Department of Mechanical EngineeringMichigan State University220 Trowbridge RdEast Lansing48824MIUSA
| | - Ju Le Tan
- National Heart Center Singapore5 Hospital DrSingapore
| | - Liang Zhong
- National Heart Center Singapore5 Hospital DrSingapore
- Duke National University of Singapore8 College RoadSingapore
| | - Martin Genet
- Mechanics Department and Solid Mechanics LaboratoryÉcole Polytechnique (CNRS, Paris‐Saclay University)Route de Saclay91128PalaiseauFrance
- M3DISIM research teamINRIA (Paris‐Saclay University)91120PalaiseauFrance
| | - Joakim Sundnes
- Simula Research Laboratory1325LysakerNorway
- Center for Cardiological InnovationSongsvannsveien 90372OsloNorway
- Department of InformaticsUniversity of OsloP.O. Box 1080, Blindern0316 OsloNorway
| | - Lik Chuan Lee
- Department of Mechanical EngineeringMichigan State University220 Trowbridge RdEast Lansing48824MIUSA
| | - Samuel T. Wall
- Simula Research Laboratory1325LysakerNorway
- Center for Cardiological InnovationSongsvannsveien 90372OsloNorway
- Department of Mathematical Science and TechnologyNorwegian University of Life SciencesUniversitetstunet 3 1430 ÅsNorway
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24
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Sack KL, Aliotta E, Ennis DB, Choy JS, Kassab GS, Guccione JM, Franz T. Construction and Validation of Subject-Specific Biventricular Finite-Element Models of Healthy and Failing Swine Hearts From High-Resolution DT-MRI. Front Physiol 2018; 9:539. [PMID: 29896107 PMCID: PMC5986944 DOI: 10.3389/fphys.2018.00539] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 04/26/2018] [Indexed: 12/15/2022] Open
Abstract
Predictive computational modeling has revolutionized classical engineering disciplines and is in the process of transforming cardiovascular research. This is particularly relevant for investigating emergent therapies for heart failure, which remains a leading cause of death globally. The creation of subject-specific biventricular computational cardiac models has been a long-term endeavor within the biomedical engineering community. Using high resolution (0.3 × 0.3 × 0.8 mm) ex vivo data, we constructed a precise fully subject-specific biventricular finite-element model of healthy and failing swine hearts. Each model includes fully subject-specific geometries, myofiber architecture and, in the case of the failing heart, fibrotic tissue distribution. Passive and active material properties are prescribed using hyperelastic strain energy functions that define a nearly incompressible, orthotropic material capable of contractile function. These materials were calibrated using a sophisticated multistep approach to match orthotropic tri-axial shear data as well as subject-specific hemodynamic ventricular targets for pressure and volume to ensure realistic cardiac function. Each mechanically beating heart is coupled with a lumped-parameter representation of the circulatory system, allowing for a closed-loop definition of cardiovascular flow. The circulatory model incorporates unidirectional fluid exchanges driven by pressure gradients of the model, which in turn are driven by the mechanically beating heart. This creates a computationally meaningful representation of the dynamic beating of the heart coupled with the circulatory system. Each model was calibrated using subject-specific experimental data and compared with independent in vivo strain data obtained from echocardiography. Our methods produced highly detailed representations of swine hearts that function mechanically in a remarkably similar manner to the in vivo subject-specific strains on a global and regional comparison. The degree of subject-specificity included in the models represents a milestone for modeling efforts that captures realism of the whole heart. This study establishes a foundation for future computational studies that can apply these validated methods to advance cardiac mechanics research.
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Affiliation(s)
- Kevin L. Sack
- Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Eric Aliotta
- Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States
| | - Daniel B. Ennis
- Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, United States
| | - Jenny S. Choy
- California Medical Innovations Institute, Inc., San Diego, CA, United States
| | - Ghassan S. Kassab
- California Medical Innovations Institute, Inc., San Diego, CA, United States
| | - Julius M. Guccione
- Department of Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Thomas Franz
- Division of Biomedical Engineering, Department of Human Biology, University of Cape Town, Cape Town, South Africa
- Bioengineering Science Research Group, Engineering Sciences, Faculty of Engineering and the Environment, University of Southampton, Southampton, United Kingdom
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25
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Liang L, Liu M, Martin C, Sun W. A machine learning approach as a surrogate of finite element analysis-based inverse method to estimate the zero-pressure geometry of human thoracic aorta. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e3103. [PMID: 29740974 DOI: 10.1002/cnm.3103] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 04/19/2018] [Indexed: 06/08/2023]
Abstract
Advances in structural finite element analysis (FEA) and medical imaging have made it possible to investigate the in vivo biomechanics of human organs such as blood vessels, for which organ geometries at the zero-pressure level need to be recovered. Although FEA-based inverse methods are available for zero-pressure geometry estimation, these methods typically require iterative computation, which are time-consuming and may be not suitable for time-sensitive clinical applications. In this study, by using machine learning (ML) techniques, we developed an ML model to estimate the zero-pressure geometry of human thoracic aorta given 2 pressurized geometries of the same patient at 2 different blood pressure levels. For the ML model development, a FEA-based method was used to generate a dataset of aorta geometries of 3125 virtual patients. The ML model, which was trained and tested on the dataset, is capable of recovering zero-pressure geometries consistent with those generated by the FEA-based method. Thus, this study demonstrates the feasibility and great potential of using ML techniques as a fast surrogate of FEA-based inverse methods to recover zero-pressure geometries of human organs.
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Affiliation(s)
- Liang Liang
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Minliang Liu
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Caitlin Martin
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
| | - Wei Sun
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, USA
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26
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Lee T, Turin SY, Gosain AK, Tepole AB. Multi-view stereo in the operating room allows prediction of healing complications in a patient-specific model of reconstructive surgery. J Biomech 2018; 74:202-206. [PMID: 29716722 DOI: 10.1016/j.jbiomech.2018.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 03/26/2018] [Accepted: 04/01/2018] [Indexed: 11/27/2022]
Abstract
Excessive mechanical stress leads to wound healing complications following reconstructive surgery. However, this knowledge is not easily applicable in clinical scenarios due to the difficulty in measuring stress contours during complex tissue rearrangement procedures. Computational tools have been proposed as an alternative to address this need, but obtaining patient specific geometries with an affordable and flexible setup has remained a challenge. Here we present a methodology to determine the stress contours from a reconstructive procedure on a patient-specific finite element model based on multi-view stereo (MVS). MVS is a noninvasive technology that allows reconstruction of 3D geometries using a standard digital camera, making it ideal for the operating room. Finite element analysis can then be used on the patient-specific geometry to perform a virtual surgery and predict regions at risk of complications. We applied our approach to the case of a 7-year-old patient who was treated to correct a cranial contour deformity and resect two large areas of scalp scarring. The simulation showed several zones of high stress, particularly near the suture lines at the distal ends of the flaps. The patient did show delayed healing and partial flap tip necrosis at one of such predicted regions at the 30-day follow up visit. Our results further establish the application of computational tools in individualized medical scenarios to advance preoperative planing and anticipate regions of concern immediately after surgery.
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Affiliation(s)
- Taeksang Lee
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA
| | - Sergey Y Turin
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Arun K Gosain
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Adrian Buganza Tepole
- School of Mechanical Engineering, Purdue University, West Lafayette, IN, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA.
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