1
|
Colman MA, Varela M, MacLeod RS, Hancox JC, Aslanidi OV. Interactions between calcium-induced arrhythmia triggers and the electrophysiological-anatomical substrate underlying the induction of atrial fibrillation. J Physiol 2024; 602:835-853. [PMID: 38372694 DOI: 10.1113/jp285740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 01/17/2024] [Indexed: 02/20/2024] Open
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia and is sustained by spontaneous focal excitations and re-entry. Spontaneous electrical firing in the pulmonary vein (PV) sleeves is implicated in AF generation. The aim of this simulation study was to identify the mechanisms determining the localisation of AF triggers in the PVs and their contribution to the genesis of AF. A novel biophysical model of the canine atria was used that integrates stochastic, spontaneous subcellular Ca2+ release events (SCRE) with regional electrophysiological heterogeneity in ionic properties and a detailed three-dimensional model of atrial anatomy, microarchitecture and patchy fibrosis. Simulations highlighted the importance of the smaller inward rectifier potassium current (IK1 ) in PV cells compared to the surrounding atria, which enabled SCRE more readily to result in delayed-afterdepolarisations that induced triggered activity. There was a leftward shift in the dependence of the probability of triggered activity on sarcoplasmic reticulum Ca2+ load. This feature was accentuated in 3D tissue compared to single cells (Δ half-maximal [Ca2+ ]SR = 58 μM vs. 22 μM). In 3D atria incorporating electrical heterogeneity, excitations preferentially emerged from the PV region. These triggered focal excitations resulted in transient re-entry in the left atrium. Addition of fibrotic patches promoted localised emergence of focal excitations and wavebreaks that had a more substantial impact on generating AF-like patterns than the PVs. Thus, a reduced IK1 , less negative resting membrane potential, and fibrosis-induced changes of the electrotonic load all contribute to the emergence of complex excitation patterns from spontaneous focal triggers. KEY POINTS: Focal excitations in the atria are most commonly associated with the pulmonary veins, but the mechanisms for this localisation are yet to be elucidated. We applied a multi-scale computational modelling approach to elucidate the mechanisms underlying such localisations. Myocytes in the pulmonary vein region of the atria have a less negative resting membrane potential and reduced time-independent potassium current; we demonstrate that both of these factors promote triggered activity in single cells and tissues. The less negative resting membrane potential also contributes to heterogeneous inactivation of the fast sodium current, which can enable re-entrant-like excitation patterns to emerge without traditional conduction block.
Collapse
Affiliation(s)
- Michael A Colman
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Marta Varela
- National Heart & Lung Institute, Faculty of Medicine, Imperial College London, London, UK
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Rob S MacLeod
- The Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, UT, USA
| | - Jules C Hancox
- School of Physiology, Pharmacology & Neuroscience, Faculty of Life Sciences, University of Bristol, Bristol, UK
| | - Oleg V Aslanidi
- School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| |
Collapse
|
2
|
Rodero C, Baptiste TMG, Barrows RK, Lewalle A, Niederer SA, Strocchi M. Advancing clinical translation of cardiac biomechanics models: a comprehensive review, applications and future pathways. FRONTIERS IN PHYSICS 2023; 11:1306210. [PMID: 38500690 PMCID: PMC7615748 DOI: 10.3389/fphy.2023.1306210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 03/20/2024]
Abstract
Cardiac mechanics models are developed to represent a high level of detail, including refined anatomies, accurate cell mechanics models, and platforms to link microscale physiology to whole-organ function. However, cardiac biomechanics models still have limited clinical translation. In this review, we provide a picture of cardiac mechanics models, focusing on their clinical translation. We review the main experimental and clinical data used in cardiac models, as well as the steps followed in the literature to generate anatomical meshes ready for simulations. We describe the main models in active and passive mechanics and the different lumped parameter models to represent the circulatory system. Lastly, we provide a summary of the state-of-the-art in terms of ventricular, atrial, and four-chamber cardiac biomechanics models. We discuss the steps that may facilitate clinical translation of the biomechanics models we describe. A well-established software to simulate cardiac biomechanics is lacking, with all available platforms involving different levels of documentation, learning curves, accessibility, and cost. Furthermore, there is no regulatory framework that clearly outlines the verification and validation requirements a model has to satisfy in order to be reliably used in applications. Finally, better integration with increasingly rich clinical and/or experimental datasets as well as machine learning techniques to reduce computational costs might increase model reliability at feasible resources. Cardiac biomechanics models provide excellent opportunities to be integrated into clinical workflows, but more refinement and careful validation against clinical data are needed to improve their credibility. In addition, in each context of use, model complexity must be balanced with the associated high computational cost of running these models.
Collapse
Affiliation(s)
- Cristobal Rodero
- Cardiac Electro-Mechanics Research Group (CEMRG), National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Tiffany M. G. Baptiste
- Cardiac Electro-Mechanics Research Group (CEMRG), National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, Faculty of Life Sciences and Medicine, King’s College London, London, United Kingdom
| | - Rosie K. Barrows
- Cardiac Electro-Mechanics Research Group (CEMRG), National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom
- Department of Biomedical Engineering, School of Biomedical Engineering and Imaging Sciences, Faculty of Life Sciences and Medicine, King’s College London, London, United Kingdom
| | - Alexandre Lewalle
- Cardiac Electro-Mechanics Research Group (CEMRG), National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Steven A. Niederer
- Cardiac Electro-Mechanics Research Group (CEMRG), National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom
- Turing Research and Innovation Cluster in Digital Twins (TRIC: DT), The Alan Turing Institute, London, United Kingdom
| | - Marina Strocchi
- Cardiac Electro-Mechanics Research Group (CEMRG), National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London, United Kingdom
| |
Collapse
|
3
|
Yang F, Wei X, Chen B, Li C, Li D, Zhang S, Lu W, Zhang L. Cardiac biophysical detailed synergetic modality rendering and visible correlation. Front Physiol 2023; 14:1086154. [PMID: 37089421 PMCID: PMC10119415 DOI: 10.3389/fphys.2023.1086154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/27/2023] [Indexed: 04/25/2023] Open
Abstract
The heart is a vital organ in the human body. Research and treatment for the heart have made remarkable progress, and the functional mechanisms of the heart have been simulated and rendered through the construction of relevant models. The current methods for rendering cardiac functional mechanisms only consider one type of modality, which means they cannot show how different types of modality, such as physical and physiological, work together. To realistically represent the three-dimensional synergetic biological modality of the heart, this paper proposes a WebGL-based cardiac synergetic modality rendering framework to visualize the cardiac physical volume data and present synergetic correspondence rendering of the cardiac electrophysiological modality. By constructing the biological detailed interactive histogram, users can implement local details rendering for the heart, which could reveal the cardiac biology details more clearly. We also present cardiac physical-physiological correlation visualization to explore cardiac biological association characteristics. Experimental results show that the proposed framework can provide favorable cardiac biological detailed synergetic modality rendering results in terms of both effectiveness and efficiency. Compared with existing methods, the framework can facilitate the study of the internal mechanism of the heart and subsequently deduce the process of initiation, development, and transformation from a healthy heart to an ill one, and thereby improve the diagnosis and treatment of cardiac disorders.
Collapse
Affiliation(s)
- Fei Yang
- School of Mechanical, Electrical and Information Engineering, Shandong University, Weihai, China
- School of Computer Science and Technology, Shandong University, Qingdao, China
| | - Xiaoxi Wei
- School of Mechanical, Electrical and Information Engineering, Shandong University, Weihai, China
| | - Bo Chen
- School of Mechanical, Electrical and Information Engineering, Shandong University, Weihai, China
| | - Chenxi Li
- Pizhou Power Supply Branch of State Grid Jiangsu Electric Power Co., Ltd., Pizhou, China
| | - Dong Li
- School of Mechanical, Electrical and Information Engineering, Shandong University, Weihai, China
| | - Shugang Zhang
- College of Computer Science and Technology, Ocean University of China, Qingdao, China
| | - Weigang Lu
- Department of Educational Technology, Ocean University of China, Qingdao, China
- *Correspondence: Weigang Lu,
| | - Lei Zhang
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States
| |
Collapse
|
4
|
OCT Meets micro-CT: A Subject-Specific Correlative Multimodal Imaging Workflow for Early Chick Heart Development Modeling. J Cardiovasc Dev Dis 2022; 9:jcdd9110379. [DOI: 10.3390/jcdd9110379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/29/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022] Open
Abstract
Structural and Doppler velocity data collected from optical coherence tomography have already provided crucial insights into cardiac morphogenesis. X-ray microtomography and other ex vivo methods have elucidated structural details of developing hearts. However, by itself, no single imaging modality can provide comprehensive information allowing to fully decipher the inner workings of an entire developing organ. Hence, we introduce a specimen-specific correlative multimodal imaging workflow combining OCT and micro-CT imaging which is applicable for modeling of early chick heart development—a valuable model organism in cardiovascular development research. The image acquisition and processing employ common reagents, lab-based micro-CT imaging, and software that is free for academic use. Our goal is to provide a step-by-step guide on how to implement this workflow and to demonstrate why those two modalities together have the potential to provide new insight into normal cardiac development and heart malformations leading to congenital heart disease.
Collapse
|
5
|
Aminu AJ, Chen W, Yin Z, Kuniewicz M, Walocha J, Perde F, Molenaar P, Iaizzo PA, Dobrzynski H, Atkinson AJ. Novel micro-computed tomography contrast agents to visualise the human cardiac conduction system and surrounding structures in hearts from normal, aged, and obese individuals. TRANSLATIONAL RESEARCH IN ANATOMY 2022. [DOI: 10.1016/j.tria.2022.100175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
|
6
|
Logantha SJRJ, Cai XJ, Yanni J, Jones CB, Stephenson RS, Stuart L, Quigley G, Monfredi O, Nakao S, Oh IY, Starborg T, Kitmitto A, Vohra A, Hutcheon RC, Corno AF, Jarvis JC, Dobrzynski H, Boyett MR, Hart G. Remodeling of the Purkinje Network in Congestive Heart Failure in the Rabbit. Circ Heart Fail 2021; 14:e007505. [PMID: 34190577 PMCID: PMC8288482 DOI: 10.1161/circheartfailure.120.007505] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Supplemental Digital Content is available in the text. Background: Purkinje fibers (PFs) control timing of ventricular conduction and play a key role in arrhythmogenesis in heart failure (HF) patients. We investigated the effects of HF on PFs. Methods: Echocardiography, electrocardiography, micro-computed tomography, quantitative polymerase chain reaction, immunohistochemistry, volume electron microscopy, and sharp microelectrode electrophysiology were used. Results: Congestive HF was induced in rabbits by left ventricular volume- and pressure-overload producing left ventricular hypertrophy, diminished fractional shortening and ejection fraction, and increased left ventricular dimensions. HF baseline QRS and corrected QT interval were prolonged by 17% and 21% (mean±SEMs: 303±6 ms HF, 249±11 ms control; n=8/7; P=0.0002), suggesting PF dysfunction and impaired ventricular repolarization. Micro-computed tomography imaging showed increased free-running left PF network volume and length in HF. mRNA levels for 40 ion channels, Ca2+-handling proteins, connexins, and proinflammatory and fibrosis markers were assessed: 50% and 35% were dysregulated in left and right PFs respectively, whereas only 12.5% and 7.5% changed in left and right ventricular muscle. Funny channels, Ca2+-channels, and K+-channels were significantly reduced in left PFs. Microelectrode recordings from left PFs revealed more negative resting membrane potential, reduced action potential upstroke velocity, prolonged duration (action potential duration at 90% repolarization: 378±24 ms HF, 249±5 ms control; n=23/38; P<0.0001), and arrhythmic events in HF. Similar electrical remodeling was seen at the left PF-ventricular junction. In the failing left ventricle, upstroke velocity and amplitude were increased, but action potential duration at 90% repolarization was unaffected. Conclusions: Severe volume- followed by pressure-overload causes rapidly progressing HF with extensive remodeling of PFs. The PF network is central to both arrhythmogenesis and contractile dysfunction and the pathological remodeling may increase the risk of fatal arrhythmias in HF patients.
Collapse
Affiliation(s)
- Sunil Jit R J Logantha
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom.,Liverpool Centre for Cardiovascular Science and Department of Cardiovascular and Metabolic Medicine (S.J.R.J.L.), University of Liverpool, United Kingdom
| | - Xue J Cai
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom
| | - Joseph Yanni
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom
| | - Caroline B Jones
- Alder Hey Children's National Health Service Foundation Trust, Liverpool, United Kingdom (C.B.J.)
| | - Robert S Stephenson
- School of Sport and Exercise Sciences, Liverpool John Moores University, United Kingdom (R.S.S., J.C.J.).,Institute of Clinical Sciences, University of Birmingham, United Kingdom (R.S.S.)
| | - Luke Stuart
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom.,Manchester University NHS Foundation Trust, United Kingdom (L.S.)
| | - Gillian Quigley
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom
| | - Oliver Monfredi
- Division of Cardiovascular Medicine, University of Virginia, Charlottesville (O.M.).,Laboratory of Cardiovascular Medicine, National Institute on Aging, NIH Biomedical Research Center, Baltimore, MD (O.M.)
| | - Shu Nakao
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom.,Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, Kyoto, Japan (S.N.)
| | - Il-Young Oh
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom.,Department of Internal Medicine, Seoul National University Bundang Hospital, Republic of Korea (I.-Y.O.)
| | - Tobias Starborg
- Wellcome Centre for Cell Matrix Research (T.S.), University of Manchester, United Kingdom
| | - Ashraf Kitmitto
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom
| | - Akbar Vohra
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom
| | - Robert C Hutcheon
- Division of Clinical Sciences (R.C.H.), University of Liverpool, United Kingdom
| | - Antonio F Corno
- Memorial Hermann Children's Hospital, University of Texas Health, Houston (A.F.C.)
| | - Jonathan C Jarvis
- School of Sport and Exercise Sciences, Liverpool John Moores University, United Kingdom (R.S.S., J.C.J.)
| | - Halina Dobrzynski
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom.,Department of Anatomy, Jagiellonian University, Medical College, Cracow, Poland (H.D.)
| | - Mark R Boyett
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom
| | - George Hart
- Division of Cardiovascular Sciences (S.J.R.J.L., X.J.C., J.Y., L.S., G.Q., S.N., I.-Y.O., A.K., A.V., H.D., M.R.B., G.H.), University of Manchester, United Kingdom
| |
Collapse
|
7
|
Sands GB, Ashton JL, Trew ML, Baddeley D, Walton RD, Benoist D, Efimov IR, Smith NP, Bernus O, Smaill BH. It's clearly the heart! Optical transparency, cardiac tissue imaging, and computer modelling. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2021; 168:18-32. [PMID: 34126113 DOI: 10.1016/j.pbiomolbio.2021.06.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 05/10/2021] [Accepted: 06/07/2021] [Indexed: 12/19/2022]
Abstract
Recent developments in clearing and microscopy enable 3D imaging with cellular resolution up to the whole organ level. These methods have been used extensively in neurobiology, but their uptake in other fields has been much more limited. Application of this approach to the human heart and effective use of the data acquired present challenges of scale and complexity. Four interlinked issues need to be addressed: 1) efficient clearing and labelling of heart tissue, 2) fast microscopic imaging of human-scale samples, 3) handling and processing of multi-terabyte 3D images, and 4) extraction of structural information in computationally tractable structure-based models of cardiac function. Preliminary studies show that each of these requirements can be achieved with the appropriate application and development of existing technologies.
Collapse
Affiliation(s)
- Gregory B Sands
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand.
| | - Jesse L Ashton
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Mark L Trew
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - David Baddeley
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand; Department of Cell Biology, Yale University, New Haven CT, 06520, USA
| | - Richard D Walton
- IHU Liryc, Fondation Bordeaux Université, Bordeaux, France; Univ. Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique, U1045, 33000, Bordeaux, France
| | - David Benoist
- IHU Liryc, Fondation Bordeaux Université, Bordeaux, France; Univ. Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique, U1045, 33000, Bordeaux, France
| | - Igor R Efimov
- IHU Liryc, Fondation Bordeaux Université, Bordeaux, France; Department of Biomedical Engineering, The George Washington University, Washington DC, 20052, USA
| | - Nicolas P Smith
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand; Queensland University of Technology, Brisbane 4000, Australia
| | - Olivier Bernus
- IHU Liryc, Fondation Bordeaux Université, Bordeaux, France; Univ. Bordeaux, Inserm, Centre de Recherche Cardio-Thoracique, U1045, 33000, Bordeaux, France
| | - Bruce H Smaill
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| |
Collapse
|
8
|
Simcock IC, Shelmerdine SC, Hutchinson JC, Sebire NJ, Arthurs OJ. Human fetal whole-body postmortem microfocus computed tomographic imaging. Nat Protoc 2021; 16:2594-2614. [PMID: 33854254 DOI: 10.1038/s41596-021-00512-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 01/05/2021] [Indexed: 02/02/2023]
Abstract
Perinatal autopsy is the standard method for investigating fetal death; however, it requires dissection of the fetus. Human fetal microfocus computed tomography (micro-CT) provides a generally more acceptable and less invasive imaging alternative for bereaved parents to determine the cause of early pregnancy loss compared with conventional autopsy techniques. In this protocol, we describe the four main stages required to image fetuses using micro-CT. Preparation of the fetus includes staining with the contrast agent potassium triiodide and takes 3-19 d, depending on the size of the fetus and the time taken to obtain consent for the procedure. Setup for imaging requires appropriate positioning of the fetus and takes 1 h. The actual imaging takes, on average, 2 h 40 min and involves initial test scans followed by high-definition diagnostic scans. Postimaging, 3 d are required to postprocess the fetus, including removal of the stain, and also to undertake artifact recognition and data transfer. This procedure produces high-resolution isotropic datasets, allowing for radio-pathological interpretations to be made and long-term digital archiving for re-review and data sharing, where required. The protocol can be undertaken following appropriate training, which includes both the use of micro-CT techniques and handling of postmortem tissue.
Collapse
Affiliation(s)
- Ian C Simcock
- Department of Clinical Radiology, Great Ormond Street Hospital for Children, London, UK.,UCL Great Ormond Street Institute of Child Health, Great Ormond Street Hospital for Children, London, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - Susan C Shelmerdine
- Department of Clinical Radiology, Great Ormond Street Hospital for Children, London, UK.,UCL Great Ormond Street Institute of Child Health, Great Ormond Street Hospital for Children, London, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - J Ciaran Hutchinson
- UCL Great Ormond Street Institute of Child Health, Great Ormond Street Hospital for Children, London, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK.,Department of Histopathology, Great Ormond Street Hospital for Children, London, UK
| | - Neil J Sebire
- UCL Great Ormond Street Institute of Child Health, Great Ormond Street Hospital for Children, London, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK.,Department of Histopathology, Great Ormond Street Hospital for Children, London, UK
| | - Owen J Arthurs
- Department of Clinical Radiology, Great Ormond Street Hospital for Children, London, UK. .,UCL Great Ormond Street Institute of Child Health, Great Ormond Street Hospital for Children, London, UK. .,NIHR Great Ormond Street Hospital Biomedical Research Centre, London, UK.
| |
Collapse
|
9
|
Leyssens L, Pestiaux C, Kerckhofs G. A Review of Ex Vivo X-ray Microfocus Computed Tomography-Based Characterization of the Cardiovascular System. Int J Mol Sci 2021; 22:3263. [PMID: 33806852 PMCID: PMC8004599 DOI: 10.3390/ijms22063263] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 12/27/2022] Open
Abstract
Cardiovascular malformations and diseases are common but complex and often not yet fully understood. To better understand the effects of structural and microstructural changes of the heart and the vasculature on their proper functioning, a detailed characterization of the microstructure is crucial. In vivo imaging approaches are noninvasive and allow visualizing the heart and the vasculature in 3D. However, their spatial image resolution is often too limited for microstructural analyses, and hence, ex vivo imaging is preferred for this purpose. Ex vivo X-ray microfocus computed tomography (microCT) is a rapidly emerging high-resolution 3D structural imaging technique often used for the assessment of calcified tissues. Contrast-enhanced microCT (CE-CT) or phase-contrast microCT (PC-CT) improve this technique by additionally allowing the distinction of different low X-ray-absorbing soft tissues. In this review, we present the strengths of ex vivo microCT, CE-CT and PC-CT for quantitative 3D imaging of the structure and/or microstructure of the heart, the vasculature and their substructures in healthy and diseased state. We also discuss their current limitations, mainly with regard to the contrasting methods and the tissue preparation.
Collapse
Affiliation(s)
- Lisa Leyssens
- Institute of Mechanics, Materials, and Civil Engineering, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium; (L.L.); (C.P.)
- Institute of Experimental and Clinical Research, Université Catholique de Louvain, 1200 Woluwe-Saint-Lambert, Belgium
| | - Camille Pestiaux
- Institute of Mechanics, Materials, and Civil Engineering, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium; (L.L.); (C.P.)
- Institute of Experimental and Clinical Research, Université Catholique de Louvain, 1200 Woluwe-Saint-Lambert, Belgium
| | - Greet Kerckhofs
- Institute of Mechanics, Materials, and Civil Engineering, Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium; (L.L.); (C.P.)
- Institute of Experimental and Clinical Research, Université Catholique de Louvain, 1200 Woluwe-Saint-Lambert, Belgium
- Department of Materials Engineering, Katholieke Universiteit Leuven, 3001 Leuven, Belgium
- Prometheus, Division of Skeletal Tissue Engineering, Katholieke Universiteit Leuven, 3000 Leuven, Belgium
| |
Collapse
|
10
|
Novo Matos J, Garcia-Canadilla P, Simcock IC, Hutchinson JC, Dobromylskyj M, Guy A, Arthurs OJ, Cook AC, Luis Fuentes V. Micro-computed tomography (micro-CT) for the assessment of myocardial disarray, fibrosis and ventricular mass in a feline model of hypertrophic cardiomyopathy. Sci Rep 2020; 10:20169. [PMID: 33214588 PMCID: PMC7678873 DOI: 10.1038/s41598-020-76809-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 11/02/2020] [Indexed: 01/15/2023] Open
Abstract
Micro-computed tomography (micro-CT) is a high-resolution imaging modality that provides accurate tissue characterization. Hypertrophic cardiomyopathy (HCM) occurs as a spontaneous disease in cats, and is characterized by myocardial hypertrophy, disarray and fibrosis, as in humans. While hypertrophy/mass (LVM) can be objectively measured, fibrosis and myocyte disarray are difficult to assess. We evaluated the accuracy of micro-CT for detection and quantification of myocardial disarray and fibrosis by direct comparison with histopathology. 29 cat hearts (12 normal and 17 HCM hearts) underwent micro-CT and pathologic examination. Myocyte orientation was assessed using structure tensor analysis by determination of helical angle (HA), fractional anisotropy (FA) and myocardial disarray index (MDI). Fibrosis was segmented and quantified based on comparison of gray-scale values in normal and fibrotic myocardium. LVM was obtained by determining myocardial volume. Myocardial segments with low FA, low MDI and disruption of normal HA transmural profile on micro-CT were associated with myocardial disarray on histopathology. FA was consistently lower in HCM than normal hearts. Assessment of fibrosis on micro-CT closely matched the histopathologic evaluation. LVM determined by micro-CT was higher in HCM than normal hearts. Micro-CT can be used to detect and quantify myocardial disarray and fibrosis and determine myocardial mass in HCM.
Collapse
Affiliation(s)
- Jose Novo Matos
- Clinical Sciences and Services, Royal Veterinary College, London, UK.
| | - Patricia Garcia-Canadilla
- Institut D'Investigacions Biomèdiques August Pi I Sunyer, Barcelona, Spain.,Institute of Cardiovascular Science, University College London, London, UK
| | - Ian C Simcock
- Department of Radiology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK.,National Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - J Ciaran Hutchinson
- Department of Histopathology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | | | - Anna Guy
- Department of Radiology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Owen J Arthurs
- Department of Radiology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK.,National Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - Andrew C Cook
- Institute of Cardiovascular Science, University College London, London, UK
| | | |
Collapse
|
11
|
Novo Matos J, Garcia-Canadilla P, Simcock IC, Hutchinson JC, Dobromylskyj M, Guy A, Arthurs OJ, Cook AC, Luis Fuentes V. Micro-computed tomography (micro-CT) for the assessment of myocardial disarray, fibrosis and ventricular mass in a feline model of hypertrophic cardiomyopathy. Sci Rep 2020. [PMID: 33214588 DOI: 10.1038/s41598-020-76809-5.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Micro-computed tomography (micro-CT) is a high-resolution imaging modality that provides accurate tissue characterization. Hypertrophic cardiomyopathy (HCM) occurs as a spontaneous disease in cats, and is characterized by myocardial hypertrophy, disarray and fibrosis, as in humans. While hypertrophy/mass (LVM) can be objectively measured, fibrosis and myocyte disarray are difficult to assess. We evaluated the accuracy of micro-CT for detection and quantification of myocardial disarray and fibrosis by direct comparison with histopathology. 29 cat hearts (12 normal and 17 HCM hearts) underwent micro-CT and pathologic examination. Myocyte orientation was assessed using structure tensor analysis by determination of helical angle (HA), fractional anisotropy (FA) and myocardial disarray index (MDI). Fibrosis was segmented and quantified based on comparison of gray-scale values in normal and fibrotic myocardium. LVM was obtained by determining myocardial volume. Myocardial segments with low FA, low MDI and disruption of normal HA transmural profile on micro-CT were associated with myocardial disarray on histopathology. FA was consistently lower in HCM than normal hearts. Assessment of fibrosis on micro-CT closely matched the histopathologic evaluation. LVM determined by micro-CT was higher in HCM than normal hearts. Micro-CT can be used to detect and quantify myocardial disarray and fibrosis and determine myocardial mass in HCM.
Collapse
Affiliation(s)
- Jose Novo Matos
- Clinical Sciences and Services, Royal Veterinary College, London, UK.
| | - Patricia Garcia-Canadilla
- Institut D'Investigacions Biomèdiques August Pi I Sunyer, Barcelona, Spain.,Institute of Cardiovascular Science, University College London, London, UK
| | - Ian C Simcock
- Department of Radiology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK.,National Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - J Ciaran Hutchinson
- Department of Histopathology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | | | - Anna Guy
- Department of Radiology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Owen J Arthurs
- Department of Radiology, Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK.,National Institute for Health Research Great Ormond Street Hospital Biomedical Research Centre, London, UK
| | - Andrew C Cook
- Institute of Cardiovascular Science, University College London, London, UK
| | | |
Collapse
|
12
|
Nguyen TD, Kadri OE, Voronov RS. An Introductory Overview of Image-Based Computational Modeling in Personalized Cardiovascular Medicine. Front Bioeng Biotechnol 2020; 8:529365. [PMID: 33102452 PMCID: PMC7546862 DOI: 10.3389/fbioe.2020.529365] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 08/31/2020] [Indexed: 02/05/2023] Open
Abstract
Cardiovascular diseases account for the number one cause of deaths in the world. Part of the reason for such grim statistics is our limited understanding of the underlying mechanisms causing these devastating pathologies, which is made difficult by the invasiveness of the procedures associated with their diagnosis (e.g., inserting catheters into the coronal artery to measure blood flow to the heart). Likewise, it is also difficult to design and test assistive devices without implanting them in vivo. However, with the recent advancements made in biomedical scanning technologies and computer simulations, image-based modeling (IBM) has arisen as the next logical step in the evolution of non-invasive patient-specific cardiovascular medicine. Yet, due to its novelty, it is still relatively unknown outside of the niche field. Therefore, the goal of this manuscript is to review the current state-of-the-art and the limitations of the methods used in this area of research, as well as their applications to personalized cardiovascular investigations and treatments. Specifically, the modeling of three different physics – electrophysiology, biomechanics and hemodynamics – used in the cardiovascular IBM is discussed in the context of the physiology that each one of them describes and the mechanisms of the underlying cardiac diseases that they can provide insight into. Only the “bare-bones” of the modeling approaches are discussed in order to make this introductory material more accessible to an outside observer. Additionally, the imaging methods, the aspects of the unique cardiac anatomy derived from them, and their relation to the modeling algorithms are reviewed. Finally, conclusions are drawn about the future evolution of these methods and their potential toward revolutionizing the non-invasive diagnosis, virtual design of treatments/assistive devices, and increasing our understanding of these lethal cardiovascular diseases.
Collapse
Affiliation(s)
- Thanh Danh Nguyen
- Otto H. York Department of Chemical and Materials Engineering, Newark College of Engineering, New Jersey Institute of Technology, Newark, NJ, United States
| | - Olufemi E Kadri
- Otto H. York Department of Chemical and Materials Engineering, Newark College of Engineering, New Jersey Institute of Technology, Newark, NJ, United States.,UC-P&G Simulation Center, University of Cincinnati, Cincinnati, OH, United States
| | - Roman S Voronov
- Otto H. York Department of Chemical and Materials Engineering, Newark College of Engineering, New Jersey Institute of Technology, Newark, NJ, United States.,Department of Biomedical Engineering, Newark College of Engineering, New Jersey Institute of Technology, Newark, NJ, United States
| |
Collapse
|
13
|
Simcock IC, Hutchinson JC, Shelmerdine SC, Matos JN, Sebire NJ, Fuentes VL, Arthurs OJ. Investigation of optimal sample preparation conditions with potassium triiodide and optimal imaging settings for microfocus computed tomography of excised cat hearts. Am J Vet Res 2020; 81:326-333. [PMID: 32228254 DOI: 10.2460/ajvr.81.4.326] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine optimal sample preparation conditions with potassium triiodide (I2KI) and optimal imaging settings for microfocus CT (micro-CT) of excised cat hearts. SAMPLE 7 excised hearts (weight range, 10 to 17.6 g) obtained from healthy adult cats after euthanasia by IV injection of pentobarbital sodium. PROCEDURES Following excision, the hearts were preserved in 10% formaldehyde solution. Six hearts were immersed in 1.25% I2KI solution (n = 3) or 2.5% I2KI solution (3) for a 12-day period. Micro-CT images were acquired at time 0 (prior to iodination) then approximately every 24 and 48 hours thereafter to determine optimal sample preparation conditions (ie, immersion time and concentration of I2KI solution). Identified optimal conditions were then used to prepare the seventh heart for imaging; changes in voltage, current, exposure time, and gain on image quality were evaluated to determine optimal settings (ie, maximal signal-to-noise and contrast-to-noise ratios). Images were obtained at a voxel resolution of 30 μm. A detailed morphological assessment of the main cardiac structures of the seventh heart was then performed. RESULTS Immersion in 2.5% I2KI solution for 48 hours was optimal for sample preparation. The optimal imaging conditions included a tube voltage of 100 kV, current of 150 μA, and exposure time of 354 milliseconds; scan duration was 12 minutes. CONCLUSIONS AND CLINICAL RELEVANCE Results provided an optimal micro-CT imaging protocol for excised cat hearts prepared with I2KI solution that could serve as a basis for future studies of micro-CT for high resolution 3-D imaging of cat hearts.
Collapse
|
14
|
Oda H, Roth HR, Sugino T, Sunaguchi N, Usami N, Oda M, Shimao D, Ichihara S, Yuasa T, Ando M, Akita T, Narita Y, Mori K. Cardiac fiber tracking on super high-resolution CT images: a comparative study. J Med Imaging (Bellingham) 2020; 7:026001. [PMID: 32206685 PMCID: PMC7064862 DOI: 10.1117/1.jmi.7.2.026001] [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: 02/13/2019] [Accepted: 02/11/2020] [Indexed: 01/14/2023] Open
Abstract
Purpose: High-resolution cardiac imaging and fiber analysis methods are required to understand cardiac anatomy. Although refraction-contrast x-ray CT (RCT) has high soft tissue contrast, it cannot be commonly used because it requires a synchrotron system. Microfocus x-ray CT (μCT) is another commercially available imaging modality. Approach: We evaluate the usefulness of μCT for analyzing fibers by quantitatively and objectively comparing the results with RCT. To do so, we scanned a rabbit heart by both modalities with our original protocol of prepared materials and compared their image-based analysis results, including fiber orientation estimation and fiber tracking. Results: Fiber orientations estimated by two modalities were closely resembled under the correlation coefficient of 0.63. Tracked fibers from both modalities matched well the anatomical knowledge that fiber orientations are different inside and outside of the left ventricle. However, the μCT volume caused incorrect tracking around the boundaries caused by stitching scanning. Conclusions: Our experimental results demonstrated that μCT scanning can be used for cardiac fiber analysis, although further investigation is required in the differences of fiber analysis results on RCT and μCT.
Collapse
Affiliation(s)
- Hirohisa Oda
- Nagoya University, Graduate School of Informatics, Nagoya, Japan
| | - Holger R Roth
- Nagoya University, Graduate School of Informatics, Nagoya, Japan
| | - Takaaki Sugino
- Nagoya University, Graduate School of Informatics, Nagoya, Japan
| | - Naoki Sunaguchi
- Nagoya University Graduate School of Medicine, Department of Radiological and Medical Laboratory Sciences, Nagoya, Japan
| | - Noriko Usami
- Nagoya University School of Medicine, Department of Tissue Engineering, Nagoya, Japan
| | - Masahiro Oda
- Nagoya University, Graduate School of Informatics, Nagoya, Japan
| | - Daisuke Shimao
- Hokkaido University of Science, Department of Radiological Technology, Sapporo, Japan
| | - Shu Ichihara
- Nagoya Medical Center, Clinical Research Center, Department of Pathology, Nagoya, Japan
| | - Tetsuya Yuasa
- Yamagata University, Graduate School of Engineering and Science, Yamagata, Japan
| | - Masami Ando
- Tokyo University of Science, Research Institute of Science and Technology, Tokyo, Japan
| | - Toshiaki Akita
- Nagoya University School of Medicine, Department of Tissue Engineering, Nagoya, Japan
| | - Yuji Narita
- Nagoya University School of Medicine, Department of Tissue Engineering, Nagoya, Japan
| | - Kensaku Mori
- Nagoya University, Graduate School of Informatics, Nagoya, Japan.,Nagoya University, Information Technology Center, Nagoya, Japan.,National Institute of Informatics, Research Center for Medical Bigdata, Tokyo, Japan
| |
Collapse
|
15
|
Investigation of the Role of Myocyte Orientations in Cardiac Arrhythmia Using Image-Based Models. Biophys J 2019; 117:2396-2408. [PMID: 31679763 PMCID: PMC6990390 DOI: 10.1016/j.bpj.2019.09.041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 09/13/2019] [Accepted: 09/23/2019] [Indexed: 11/24/2022] Open
Abstract
Cardiac electrical excitation-propagation is influenced by myocyte orientations (cellular organization). Quantitatively understanding this relationship presents a significant research challenge, especially during arrhythmias in which excitation patterns become complex. Tissue-scale simulations of cardiac electrophysiology, incorporating both dynamic action potential behavior and image-based myocardial architecture, provide an approach to investigate three-dimensional (3D) propagation of excitation waves in the heart. In this study, we aimed to assess the importance of natural variation in myocyte orientations on cardiac arrhythmogenesis using 3D tissue electrophysiology simulations. Three anatomical models (i.e., describing myocyte orientations) of healthy rat ventricles—obtained using diffusion tensor imaging at 100 μm resolution—were registered to a single biventricular geometry (i.e., a single cardiac shape), in which the myocyte orientations could be represented by each of the diffusion tensor imaging data sets or by an idealized rule-based description. The Fenton-Karma cellular excitation model was modified to reproduce rat ventricular action potential duration restitution to create reaction-diffusion cardiac electrophysiology models. Over 250 3D simulations were performed to investigate the effects of myocyte orientations on the following: 1) ventricular activation, 2) location-dependent arrhythmia induction via rapid pacing, and 3) dynamics of re-entry averaged over multiple episodes. It was shown that 1) myocyte orientation differences manifested themselves in local activation times, but the influence on total activation time was small; 2) differences in myocyte orientations could critically affect the inducibility and persistence of arrhythmias for specific stimulus-location/cycle-length combinations; and 3) myocyte orientations alone could be an important determinant of scroll wave break, although no significant differences were observed in averaged arrhythmia dynamics between the four myocyte orientation scenarios considered. Our results show that myocyte orientations are an important determinant of arrhythmia inducibility, persistence, and scroll wave break. These findings suggest that where specificity is desired (for example, when predicting location-dependent, patient-specific arrhythmia inducibility), subject-specific myocyte orientations may be important.
Collapse
|
16
|
Sakurai Y, Ikeda Y. Development of a contrast-enhanced micro computed tomography protocol for the oval squid (Sepioteuthis lessoniana) brain. Microsc Res Tech 2019; 82:1941-1952. [PMID: 31411804 DOI: 10.1002/jemt.23363] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 06/28/2019] [Accepted: 08/01/2019] [Indexed: 01/13/2023]
Abstract
Coleoid cephalopods (squid, cuttlefish, and octopus) have a well-developed and complex central nervous system. Its absolute size is the largest among invertebrates, and the brain-to-body mass ratio is larger than that of fish and reptiles and equivalent to that of birds and mammals. Although a number of histological studies have been conducted on the brains of cephalopods, most of them used a light microscope or an electron microscope, which show the microstructure of the brain, but often cannot image the whole brain instantaneously. Of late, micro computed tomography (CT) has gained popularity for imaging animal brains because it allows for noninvasive three-dimensional (3D) reconstruction and preprocessing that are not cumbersome. To perform micro-CT on cephalopod brains, we first tested conditions suitable for preprocessing, paying special attention to staining conditions that would provide high contrast images. Four agents, iodine in 99.5% ethanol, iodine potassium iodide in water (IKI), phosphotungstic acid in 70% ethanol, and nonionic iodinated contrast agent in water, were tested at various concentrations and durations on brain of juvenile oval squid. To evaluate the quality of staining, we calculated the contrast ratio of the two-dimensional (2D) images and compared 3D segmentation of the best and worst 2D images. We concluded that 3% IKI staining for 7 days was the best combination to enhance the images contrast of the oval squid brain, in which each brain lobe was clearly detected and 3D segmentation of the whole brain was possible. The wider applicability of this preprocessing method for micro-CT of the brains of other cephalopods is discussed.
Collapse
Affiliation(s)
- Yuma Sakurai
- Department of Marine and Environmental Sciences, Graduate School of Engineering and Science, University of the Ryukyus, Okinawa, Japan
| | - Yuzuru Ikeda
- Faculty of Science, Department of Chemistry, Biology, and Marine Science, University of the Ryukyus, Okinawa, Japan
| |
Collapse
|
17
|
Baier W, Mangham C, Warnett JM, Payne M, Painter M, Williams MA. Using histology to evaluate micro-CT findings of trauma in three post-mortem samples — First steps towards method validation. Forensic Sci Int 2019; 297:27-34. [DOI: 10.1016/j.forsciint.2019.01.027] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 01/21/2019] [Accepted: 01/24/2019] [Indexed: 10/27/2022]
|
18
|
Starborg T, O'Sullivan JDB, Carneiro CM, Behnsen J, Else KJ, Grencis RK, Withers PJ. Experimental steering of electron microscopy studies using prior X-ray computed tomography. Ultramicroscopy 2019; 201:58-67. [PMID: 30928781 PMCID: PMC6504073 DOI: 10.1016/j.ultramic.2019.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/26/2019] [Accepted: 03/03/2019] [Indexed: 01/23/2023]
Abstract
Using microCT pre-scans to accurately steer serial block face SEM. High throughput screening and mapping samples to reduce time hunting for features of interest. Using microCT to optimise specimen preparation and staining. Using microCT to guide site-specific TEM sample preparation.
Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) can provide unrivalled high-resolution images of specific features and volumes of interest. However, the regions interrogated are typically very small, and sample preparation is both time-consuming and destructive. Here we consider how prior X-ray micro-computed tomography (microCT) presents an opportunity to increase the efficiency of electron microscopy in biology. We demonstrate how it can be used to; select the most promising samples and target site-specific locations; provide a wider context of the location being interrogated (multiscale correlative imaging); guide sample preparation and 3D imaging schemes; as well as quantify the effects of destructive sample preparation and staining procedures. We present a workflow utilising open source software in which microCT can be used either broadly, or precisely, to experimentally steer and inform subsequent electron microscopy studies. As automated sample registration procedures are developed to enable correlative microscopy, experimental steering by prior CT could be beneficially routinely incorporated into many experimental workflows.
Collapse
Affiliation(s)
- Tobias Starborg
- Wellcome Centre for Cell Matrix Research, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
| | - James D B O'Sullivan
- Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Claudia Martins Carneiro
- Immunopathology Laboratory, NUPEB, Federal University of Ouro Preto, Campus Universitário Morro do Cruzeiro, 35400-000 Ouro Preto, MG, Brazil
| | - Julia Behnsen
- Henry Royce Institute for Advanced Materials, School of Materials, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Kathryn J Else
- Faculty of Biology Medicine and Health, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Richard K Grencis
- Wellcome Centre for Cell Matrix Research, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Philip J Withers
- Henry Royce Institute for Advanced Materials, School of Materials, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| |
Collapse
|
19
|
Contrast-Enhanced MicroCT for Virtual 3D Anatomical Pathology of Biological Tissues: A Literature Review. CONTRAST MEDIA & MOLECULAR IMAGING 2019; 2019:8617406. [PMID: 30944550 PMCID: PMC6421764 DOI: 10.1155/2019/8617406] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 02/07/2019] [Indexed: 11/17/2022]
Abstract
To date, the combination of histological sectioning, staining, and microscopic assessment of the 2D sections is still the golden standard for structural and compositional analysis of biological tissues. X-ray microfocus computed tomography (microCT) is an emerging 3D imaging technique with high potential for 3D structural analysis of biological tissues with a complex and heterogeneous 3D structure, such as the trabecular bone. However, its use has been mostly limited to mineralized tissues because of the inherently low X-ray absorption of soft tissues. To achieve sufficient X-ray attenuation, chemical compounds containing high atomic number elements that bind to soft tissues have been recently adopted as contrast agents (CAs) for contrast-enhanced microCT (CE-CT); this novel technique is very promising for quantitative "virtual" 3D anatomical pathology of both mineralized and soft biological tissues. In this paper, we provided a review of the advances in CE-CT since the very first reports on the technology to date. Perfusion CAs for in vivo imaging have not been discussed, as the focus of this review was on CAs that bind to the tissue of interest and that are, thus, used for ex vivo imaging of biological tissues. As CE-CT has mostly been applied for the characterization of musculoskeletal tissues, we have put specific emphasis on these tissues. Advantages and limitations of multiple CAs for different musculoskeletal tissues have been highlighted, and their reproducibility has been discussed. Additionally, the advantages of the "full" 3D CE-CT information have been pinpointed, and its importance for more detailed structural, spatial, and functional characterization of the tissues of interest has been shown. Finally, the remaining challenges that are still hampering a broader adoption of CE-CT have been highlighted, and suggestions have been made to move the field of CE-CT imaging one step further towards a standard accepted tool for quantitative virtual 3D anatomical pathology.
Collapse
|
20
|
Koç MM, Aslan N, Kao AP, Barber AH. Evaluation of X-ray tomography contrast agents: A review of production, protocols, and biological applications. Microsc Res Tech 2019; 82:812-848. [PMID: 30786098 DOI: 10.1002/jemt.23225] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 01/02/2019] [Accepted: 01/12/2019] [Indexed: 12/25/2022]
Abstract
X-ray computed tomography is a strong tool that finds many applications both in medical applications and in the investigation of biological and nonbiological samples. In the clinics, X-ray tomography is widely used for diagnostic purposes whose three-dimensional imaging in high resolution helps physicians to obtain detailed image of investigated regions. Researchers in biological sciences and engineering use X-ray tomography because it is a nondestructive method to assess the structure of their samples. In both medical and biological applications, visualization of soft tissues and structures requires special treatment, in which special contrast agents are used. In this detailed report, molecule-based and nanoparticle-based contrast agents used in biological applications to enhance the image quality were compiled and reported. Special contrast agent applications and protocols to enhance the contrast for the biological applications and works to develop nanoparticle contrast agents to enhance the contrast for targeted drug delivery and general imaging applications were also assessed and listed.
Collapse
Affiliation(s)
- Mümin Mehmet Koç
- School of Engineering, University of Portsmouth, Portsmouth, United Kingdom.,Department of Physics, Kirklareli University, Kirklareli, Turkey
| | - Naim Aslan
- Department of Metallurgical and Materials Engineering, Munzur University, Tunceli, Turkey
| | - Alexander P Kao
- School of Engineering, University of Portsmouth, Portsmouth, United Kingdom
| | - Asa H Barber
- School of Engineering, London South Bank University, London, United Kingdom
| |
Collapse
|
21
|
Sullivan SP, McGechie FR, Middleton KM, Holliday CM. 3D Muscle Architecture of the Pectoral Muscles of European Starling ( Sturnus vulgaris). Integr Org Biol 2019; 1:oby010. [PMID: 33791517 PMCID: PMC7671135 DOI: 10.1093/iob/oby010] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Avian flight is achieved through a number of modifications to the body, including the pectoral girdle, yet little is known about the architecture of the pectoral musculature. Muscle architecture is a critical variable in determining the biomechanical function of the vertebrate musculoskeletal system; however, accurate three-dimensional (3D) understanding of muscle architecture has been historically difficult to acquire. Here, we present a musculoskeletal model of a European starling (Sturnus vulgaris) pectoral girdle generated from iodine contrast-enhanced micro-computed-tomography (CT) data and 3D fiber tracking analysis. We used a template-based fiber-tracking algorithm to reconstruct muscle fibers in 3D based on grayscale differences in CT images, which allowed us to estimate fascicle lengths, pennation angles, muscle volumes, and physiological cross-sectional area. Our modeled muscles were qualitatively accurate; however, quantitative muscle architecture data differed between digital and traditional gross-dissection methods reflecting the complex organization of the tissue and differing natures of data collection. We found that model quality is affected by the resolution of CT image data and the fiber-tracking program’s input parameters. Nonetheless, digital fiber tracking offers numerous advantages over gross-dissection methods, most importantly, the ability to visualize and quantify entire muscles in three-dimensions, yielding a much more accurate estimation of whole muscle architecture.
Collapse
Affiliation(s)
- S P Sullivan
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA
| | - F R McGechie
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA
| | - K M Middleton
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA
| | - C M Holliday
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA
| |
Collapse
|
22
|
Kawashima T, Sato F. Clarifying the anatomy of the atrioventricular node artery. Int J Cardiol 2018; 269:158-164. [DOI: 10.1016/j.ijcard.2018.07.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 06/29/2018] [Accepted: 07/03/2018] [Indexed: 12/12/2022]
|
23
|
Stephenson RS, Rowley-Nobel J, Jones CB, Guerrero R, Lowe T, Zhao J, Zhang H, Jarvis JC. Morphological Substrates for Atrial Arrhythmogenesis in a Heart With Atrioventricular Septal Defect. Front Physiol 2018; 9:1071. [PMID: 30190677 PMCID: PMC6115687 DOI: 10.3389/fphys.2018.01071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/17/2018] [Indexed: 11/13/2022] Open
Abstract
Due to advances in corrective surgery, congenital heart disease has an ever growing patient population. Atrial arrhythmias are frequently observed pre- and post-surgical correction. Pharmaceutical antiarrhythmic therapy is not always effective, therefore many symptomatic patients undergo catheter ablation therapy. In patients with atrioventricular septal defects (AVSD), ablation therapy itself has mixed success; arrhythmogenic recurrences are common, and because of the anatomical displacement of the atrioventricular node, 3-degree heart block post-ablation is a real concern. In order to develop optimal and safe ablation strategies, the field of congenital cardiac electrophysiology must combine knowledge from clinical electrophysiology with a thorough understanding of the anatomical substrates for arrhythmias. Using image-based analysis and multi-cellular mathematical modeling of electrical activation, we show how the anatomical alterations characteristic of an AVSD serve as arrhythmogenic substrates. Using ex-vivo contrast enhanced micro-computed tomography we imaged post-mortem the heart of a 5 month old male with AVSD at an isometric spatial resolution of 38 μm. Morphological analysis revealed the 3D disposition of the cardiac conduction system for the first time in an intact heart with this human congenital malformation. We observed displacement of the compact atrioventricular node inferiorly to the ostium of the coronary sinus. Myocyte orientation analysis revealed that the normal arrangement of the major atrial muscle bundles was preserved but was modified in the septal region. Models of electrical activation suggest the disposition of the myocytes within the atrial muscle bundles associated with the "fast pathway," together with the displaced atrioventricular node, serve as potential substrates for re-entry and possibly atrial fibrillation. This study used archived human hearts, showing them to be a valuable resource for the mathematical modeling community, and opening new possibilities for the investigations of arrhythmogenesis and ablation strategies in the congenitally malformed heart.
Collapse
Affiliation(s)
- Robert S Stephenson
- Comparative Medicine Lab, Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Jack Rowley-Nobel
- School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Caroline B Jones
- Department of Cardiology, Alder Hey Children's Hospital, Liverpool, United Kingdom
| | - Rafael Guerrero
- Department of Cardiac Surgery, Alder Hey Children's Hospital, Liverpool, United Kingdom
| | - Tristan Lowe
- Manchester X-ray Imaging Facility, Photon Science Institute, University of Manchester, Manchester, United Kingdom
| | - Jichao Zhao
- Auckland Bioengineering Institute, Auckland University, Auckland, New Zealand
| | - Henggui Zhang
- School of Physics and Astronomy, University of Manchester, Manchester, United Kingdom
| | - Jonathan C Jarvis
- School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| |
Collapse
|
24
|
Gonzalez-Tendero A, Zhang C, Balicevic V, Cárdenes R, Loncaric S, Butakoff C, Paun B, Bonnin A, Garcia-Cañadilla P, Muñoz-Moreno E, Gratacós E, Crispi F, Bijnens B. Whole heart detailed and quantitative anatomy, myofibre structure and vasculature from X-ray phase-contrast synchrotron radiation-based micro computed tomography. Eur Heart J Cardiovasc Imaging 2018; 18:732-741. [PMID: 28329054 DOI: 10.1093/ehjci/jew314] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 11/28/2016] [Indexed: 11/13/2022] Open
Abstract
Background While individual cardiac myocytes only have a limited ability to shorten, the heart efficiently pumps a large volume-fraction thanks to a cell organization in a complex 3D fibre structure. Subclinical subtle cardiac structural remodelling is often present before symptoms arise. Understanding and early detection of these subtle changes is crucial for diagnosis and prevention. Additionally, personalized computational modelling requires knowledge on the multi-scale structure of the whole heart and vessels. Methods and Results We developed a rapid acquisition together with visualization and quantification methods of the integrated microstructure of whole in-vitro rodents hearts using synchrotron based X-ray phase-contrast tomography. These images are formed not only by X-ray absorption by the tissue but also by wave propagation phenomena, enhancing structural information, thus allowing to raise tissue contrast to an unprecedented level. We used a (ex-vivo) normal rat heart and fetal rabbit hearts suffering intrauterine growth restriction as a model of subclinical cardiac remodelling to illustrate the strengths and potential of the technique. For comparison, histology and diffusion tensor magnetic resonance imaging was performed. Conclusions We have developed a novel, high resolution, image acquisition, and quantification approach to study a whole in-vitro heart at myofibre resolution, providing integrated 3D structural information at microscopic level without any need of tissue slicing and processing. This superior imaging approach opens up new possibilities for a systems approach towards analysing cardiac structure and function, providing rapid acquisition of quantitative microstructure of the heart in a near native state.
Collapse
Affiliation(s)
- Anna Gonzalez-Tendero
- Fetal i+D Fetal Medicine Research Center, BCNatal-Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Deu), IDIBAPS, University of Barcelona, and Centre for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain
| | - Chong Zhang
- PhySense, DTIC, Universitat Pompeu Fabra, Barcelona, Spain.,CellNetworks, Heidelberg, Germany
| | - Vedrana Balicevic
- Faculty of Electrical Engineering and Computing, University of Zagreb, Zagreb, Croatia
| | - Rubén Cárdenes
- Fetal i+D Fetal Medicine Research Center, BCNatal-Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Deu), IDIBAPS, University of Barcelona, and Centre for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain.,PhySense, DTIC, Universitat Pompeu Fabra, Barcelona, Spain
| | - Sven Loncaric
- Faculty of Electrical Engineering and Computing, University of Zagreb, Zagreb, Croatia
| | | | - Bruno Paun
- PhySense, DTIC, Universitat Pompeu Fabra, Barcelona, Spain
| | - Anne Bonnin
- European Synchrotron Radiation Facility, Grenoble, France.,Paul Scherrer Institut, Villigen, Switzerland
| | | | - Emma Muñoz-Moreno
- Fetal i+D Fetal Medicine Research Center, BCNatal-Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Deu), IDIBAPS, University of Barcelona, and Centre for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain
| | - Eduard Gratacós
- Fetal i+D Fetal Medicine Research Center, BCNatal-Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Deu), IDIBAPS, University of Barcelona, and Centre for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain
| | - Fatima Crispi
- Fetal i+D Fetal Medicine Research Center, BCNatal-Barcelona Center for Maternal-Fetal and Neonatal Medicine (Hospital Clínic and Hospital Sant Joan de Deu), IDIBAPS, University of Barcelona, and Centre for Biomedical Research on Rare Diseases (CIBER-ER), Barcelona, Spain
| | - Bart Bijnens
- PhySense, DTIC, Universitat Pompeu Fabra, Barcelona, Spain.,ICREA, Barcelona, Spain
| |
Collapse
|
25
|
Hedrick BP, Yohe L, Vander Linden A, Dávalos LM, Sears K, Sadier A, Rossiter SJ, Davies KTJ, Dumont E. Assessing Soft-Tissue Shrinkage Estimates in Museum Specimens Imaged With Diffusible Iodine-Based Contrast-Enhanced Computed Tomography (diceCT). MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2018; 24:284-291. [PMID: 29916341 DOI: 10.1017/s1431927618000399] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The increased accessibility of soft-tissue data through diffusible iodine-based contrast-enhanced computed tomography (diceCT) enables comparative biologists to increase the taxonomic breadth of their studies with museum specimens. However, it is still unclear how soft-tissue measurements from preserved specimens reflect values from freshly collected specimens and whether diceCT preparation may affect these measurements. Here, we document and evaluate the accuracy of diceCT in museum specimens based on the soft-tissue reconstructions of brains and eyes of five bats. Based on proxies, both brains and eyes were roughly 60% of the estimated original sizes when first imaged. However, these structures did not further shrink significantly over a 4-week staining interval, and 1 week in 2.5% iodine-based solution yielded sufficient contrast for differentiating among soft-tissues. Compared to six "fresh" bat specimens imaged shortly after field collection (not fixed in ethanol), the museum specimens had significantly lower relative volumes of the eyes and brains. Variation in field preparation techniques and conditions, and long-term storage in ethanol may be the primary causes of shrinkage in museum specimens rather than diceCT staining methodology. Identifying reliable tissue-specific correction factors to adjust for the shrinkage now documented in museum specimens requires future work with larger samples.
Collapse
Affiliation(s)
- Brandon P Hedrick
- 1Department of Organismic and Evolutionary Biology,Harvard University,Cambridge,MA 02138,USA
| | - Laurel Yohe
- 2Department of Ecology and Evolution,Stony Brook University,650 Life Sciences Building,Stony Brook,NY 11794,USA
| | - Abby Vander Linden
- 3Graduate Program in Organismic and Evolutionary Biology,University of Massachusetts Amherst,Amherst,MA 01003,USA
| | - Liliana M Dávalos
- 2Department of Ecology and Evolution,Stony Brook University,650 Life Sciences Building,Stony Brook,NY 11794,USA
| | - Karen Sears
- 4Department of Animal Biology,University of Illinois at Urbana-Champaign,Urbana,IL 61801,USA
| | - Alexa Sadier
- 4Department of Animal Biology,University of Illinois at Urbana-Champaign,Urbana,IL 61801,USA
| | - Stephen J Rossiter
- 5School of Biological and Chemical Sciences,Queen Mary University of London,London E1 4NS,UK
| | - Kalina T J Davies
- 5School of Biological and Chemical Sciences,Queen Mary University of London,London E1 4NS,UK
| | - Elizabeth Dumont
- 6School of Natural Sciences,University of California-Merced,Merced,CA 95343,USA
| |
Collapse
|
26
|
Martins de Souza E Silva J, Utsch J, Kimm MA, Allner S, Epple MF, Achterhold K, Pfeiffer F. Dual-energy micro-CT for quantifying the time-course and staining characteristics of ex-vivo animal organs treated with iodine- and gadolinium-based contrast agents. Sci Rep 2017; 7:17387. [PMID: 29234002 PMCID: PMC5727238 DOI: 10.1038/s41598-017-17064-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 11/20/2017] [Indexed: 01/12/2023] Open
Abstract
Chemical staining of soft-tissues can be used as a strategy to increase their low inherent contrast in X-ray absorption micro-computed tomography (micro-CT), allowing to obtain fast three-dimensional structural information of animal organs. Though some staining agents are commonly used in this context, little is known about the staining agents' ability to stain specific types of tissues; the times necessary to provide a sufficient contrast; and the effect of staining solution in distorting the tissue. Here we contribute to studies of animal organs (mouse heart and lungs) using staining combined with dual-energy micro-CT (DECT). DECT was used in order to obtain an additional quantitative measure for the amount of staining agents within the sample in 3D maps. Our results show that the two staining solutions used in this work diffuse differently in the tissues studied, the staining times of some tens of minutes already produce high-quality micro-CT images and, at the concentrations applied in this work, the staining solutions tested do not cause relevant tissue distortions. While one staining solution provides images of the general morphology of the organs, the other reveals organs' features in the order of a hundred micrometers.
Collapse
Affiliation(s)
- Juliana Martins de Souza E Silva
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany.
- Institute of Physics, Martin Luther University, Halle-Wittenberg, Germany.
| | - Julian Utsch
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Melanie A Kimm
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Germany
| | - Sebastian Allner
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Michael F Epple
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Klaus Achterhold
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Germany
- Institute for Advanced Study, Technical University of Munich, 85748, Garching, Germany
| |
Collapse
|
27
|
Tensile rupture of medial arterial tissue studied by X-ray micro-tomography on stained samples. J Mech Behav Biomed Mater 2017; 78:362-368. [PMID: 29207329 DOI: 10.1016/j.jmbbm.2017.11.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 11/14/2017] [Accepted: 11/21/2017] [Indexed: 01/01/2023]
Abstract
Detailed characterization of damage and rupture mechanics of arteries is one the current challenges in vascular biomechanics, which requires developing suitable experimental approaches. This paper introduces an approach using in situ tensile tests in an X-ray micro-tomography setup to observe mechanisms of damage initiation and progression in medial layers of porcine aortic samples. The technique requires the use of sodium polytungstate as a contrast agent, of which the conditions for use are detailed in this paper. Immersion of the samples during 24h in a 15g/L concentrated solution provided the best compromise for viewing musculo-elastic units in this tissue. The process of damage initiation, delamination and rupture of medial tissue under tensile loading was observed and can be described as an elementary process repeating several times until complete failure. This elementary process initiates with a sudden mode I fracture of a group of musculo-elastic units, followed by an elastic recoil of these units, causing mode II separation of these, hence a delamination plane. The presented experimental approach constitutes a basis for observation of other constituents, or for investigations on other tissues and damage mechanisms.
Collapse
|
28
|
Abstract
X-ray micro-computed tomography (μCT) is a technique which can obtain three-dimensional images of a sample, including its internal structure, without the need for destructive sectioning. Here, we review the capability of the technique and examine its potential to provide novel insights into the lifestyles of parasites embedded within host tissue. The current capabilities and limitations of the technology in producing contrast in soft tissues are discussed, as well as the potential solutions for parasitologists looking to apply this technique. We present example images of the mouse whipworm Trichuris muris and discuss the application of μCT to provide unique insights into parasite behaviour and pathology, which are inaccessible to other imaging modalities.
Collapse
|
29
|
Stephenson RS, Atkinson A, Kottas P, Perde F, Jafarzadeh F, Bateman M, Iaizzo PA, Zhao J, Zhang H, Anderson RH, Jarvis JC, Dobrzynski H. High resolution 3-Dimensional imaging of the human cardiac conduction system from microanatomy to mathematical modeling. Sci Rep 2017; 7:7188. [PMID: 28775383 PMCID: PMC5543124 DOI: 10.1038/s41598-017-07694-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 07/03/2017] [Indexed: 12/23/2022] Open
Abstract
Cardiac arrhythmias and conduction disturbances are accompanied by structural remodelling of the specialised cardiomyocytes known collectively as the cardiac conduction system. Here, using contrast enhanced micro-computed tomography, we present, in attitudinally appropriate fashion, the first 3-dimensional representations of the cardiac conduction system within the intact human heart. We show that cardiomyocyte orientation can be extracted from these datasets at spatial resolutions approaching the single cell. These data show that commonly accepted anatomical representations are oversimplified. We have incorporated the high-resolution anatomical data into mathematical simulations of cardiac electrical depolarisation. The data presented should have multidisciplinary impact. Since the rate of depolarisation is dictated by cardiac microstructure, and the precise orientation of the cardiomyocytes, our data should improve the fidelity of mathematical models. By showing the precise 3-dimensional relationships between the cardiac conduction system and surrounding structures, we provide new insights relevant to valvar replacement surgery and ablation therapies. We also offer a practical method for investigation of remodelling in disease, and thus, virtual pathology and archiving. Such data presented as 3D images or 3D printed models, will inform discussions between medical teams and their patients, and aid the education of medical and surgical trainees.
Collapse
Affiliation(s)
- Robert S Stephenson
- Comparative Medicine Lab, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Andrew Atkinson
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Petros Kottas
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - Filip Perde
- National Institute of Legal Medicine, Bucharest, Romania
| | - Fatemeh Jafarzadeh
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Mike Bateman
- The Visible Heart Laboratory, University of Minnesota, Minneapolis, USA
| | - Paul A Iaizzo
- The Visible Heart Laboratory, University of Minnesota, Minneapolis, USA
| | - Jichao Zhao
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Henggui Zhang
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - Robert H Anderson
- Institute of Genetic Medicine, University of Newcastle, Newcastle, UK
| | - Jonathan C Jarvis
- School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.
| | - Halina Dobrzynski
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
| |
Collapse
|
30
|
Can the Drosophila model help in paving the way for translational medicine in heart failure? Biochem Soc Trans 2017; 44:1549-1560. [PMID: 27911738 DOI: 10.1042/bst20160017c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 08/02/2016] [Accepted: 08/15/2016] [Indexed: 01/09/2023]
Abstract
Chronic heart failure is a common consequence of various heart diseases. Mechanical force is known to play a key role in heart failure development through regulating cardiomyocyte hypertrophy. In order to understand the complex disease mechanism, this article discussed a multi-disciplinary approach that may aid the illustration of heart failure molecular process.
Collapse
|
31
|
Ferrer-Albero A, Godoy EJ, Lozano M, Martínez-Mateu L, Atienza F, Saiz J, Sebastian R. Non-invasive localization of atrial ectopic beats by using simulated body surface P-wave integral maps. PLoS One 2017; 12:e0181263. [PMID: 28704537 PMCID: PMC5509320 DOI: 10.1371/journal.pone.0181263] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Accepted: 06/28/2017] [Indexed: 01/22/2023] Open
Abstract
Non-invasive localization of continuous atrial ectopic beats remains a cornerstone for the treatment of atrial arrhythmias. The lack of accurate tools to guide electrophysiologists leads to an increase in the recurrence rate of ablation procedures. Existing approaches are based on the analysis of the P-waves main characteristics and the forward body surface potential maps (BSPMs) or on the inverse estimation of the electric activity of the heart from those BSPMs. These methods have not provided an efficient and systematic tool to localize ectopic triggers. In this work, we propose the use of machine learning techniques to spatially cluster and classify ectopic atrial foci into clearly differentiated atrial regions by using the body surface P-wave integral map (BSPiM) as a biomarker. Our simulated results show that ectopic foci with similar BSPiM naturally cluster into differentiated non-intersected atrial regions and that new patterns could be correctly classified with an accuracy of 97% when considering 2 clusters and 96% for 4 clusters. Our results also suggest that an increase in the number of clusters is feasible at the cost of decreasing accuracy.
Collapse
Affiliation(s)
- Ana Ferrer-Albero
- Centro de Investigación e Innovación en Bioingeniería (Ci2B), Universitat Politècnica de València, Valencia, Spain
- * E-mail:
| | - Eduardo J. Godoy
- Computational Multiscale Physiology Lab (CoMMLab), Department of Computer Science, Universitat de Valencia, Valencia, Spain
| | - Miguel Lozano
- Computational Multiscale Physiology Lab (CoMMLab), Department of Computer Science, Universitat de Valencia, Valencia, Spain
| | - Laura Martínez-Mateu
- Centro de Investigación e Innovación en Bioingeniería (Ci2B), Universitat Politècnica de València, Valencia, Spain
| | | | - Javier Saiz
- Centro de Investigación e Innovación en Bioingeniería (Ci2B), Universitat Politècnica de València, Valencia, Spain
| | - Rafael Sebastian
- Computational Multiscale Physiology Lab (CoMMLab), Department of Computer Science, Universitat de Valencia, Valencia, Spain
| |
Collapse
|
32
|
Yang F, Zhang L, Lu W, Zhang Y, Zuo W, Wang K, Zhang H. A composite visualization method for electrophysiology-morphous merging of human heart. Biomed Eng Online 2017; 16:70. [PMID: 28595607 PMCID: PMC5465514 DOI: 10.1186/s12938-017-0368-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 06/01/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Electrophysiological behavior is of great importance for analyzing the cardiac functional mechanism under cardiac physiological and pathological condition. Due to the complexity of cardiac structure and biophysiological function, visualization of a cardiac electrophysiological model compositively is still a challenge. The lack of either modality of the whole organ structure or cardiac electrophysiological behaviors makes analysis of the intricate mechanisms of cardiac dynamic function a difficult task. This study aims at exploring 3D conduction of stimulus and electrical excitation reactivity on the level of organ with the authentic fine cardiac anatomy structure. METHODS In this paper, a cardiac electrical excitation propagation model is established based on the human cardiac cross-sectional data to explore detailed cardiac electrical activities. A novel biophysical merging visualization method is then presented for biophysical integration of cardiac anatomy and electrophysiological properties in the form of the merging optical model, which provides the corresponding position, spatial relationship and the whole process in 3D space with the context of anatomical structure for representing the biophysical detailed electrophysiological activity. RESULTS The visualization result present the action potential propagation of the left ventricle within the excitation cycle with the authentic fine cardiac organ anatomy. In the visualized images, all vital organs are identified and distinguished without ambiguity. The three dimensional spatial position, relation and the process of cardiac excitation conduction and re-entry propagation in the anatomical structure during the phase of depolarization and repolarization is also shown in the result images, which exhibits the performance of a more detailed biophysical understanding of the electrophysiological kinetics of human heart in vivo. CONCLUSIONS Results suggest that the proposed merging optical model can merge cardiac electrophysiological activity with the anatomy structure. By specifying the respective opacity for the cardiac anatomy structure and the electrophysiological model in the merging attenuation function, the visualized images can provide an in-depth insight into the biophysical detailed cardiac functioning phenomena and the corresponding electrophysiological behavior mechanism, which is helpful for further speculating cardiac physiological and pathological responses and is fundamental to the cardiac research and clinical diagnoses.
Collapse
Affiliation(s)
- Fei Yang
- School of Mechanical, Electrical & Information Engineering, Shandong University, Weihai, China
| | - Lei Zhang
- School of Art and Design, Harbin University, Harbin, China
| | - Weigang Lu
- Department of Educational Technology, Ocean University of China, Qingdao, China.
| | - Yue Zhang
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Wangmeng Zuo
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Kuanquan Wang
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Henggui Zhang
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China.,School of Physics and Astronomy, University of Manchester, Manchester, M139PL, UK
| |
Collapse
|
33
|
Lutton EJ, Lammers WJEP, James S, van den Berg HA, Blanks AM. A computational method for three-dimensional reconstruction of the microarchitecture of myometrial smooth muscle from histological sections. PLoS One 2017; 12:e0173404. [PMID: 28301486 PMCID: PMC5354307 DOI: 10.1371/journal.pone.0173404] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 02/13/2017] [Indexed: 11/25/2022] Open
Abstract
Background The fibrous structure of the myometrium has previously been characterised at high resolutions in small tissue samples (< 100 mm3) and at low resolutions (∼500 μm per voxel edge) in whole-organ reconstructions. However, no high-resolution visualisation of the myometrium at the organ level has previously been attained. Methods and results We have developed a technique to reconstruct the whole myometrium from serial histological slides, at a resolution of approximately 50 μm per voxel edge. Reconstructions of samples taken from human and rat uteri are presented here, along with histological verification of the reconstructions and detailed investigation of the fibrous structure of these uteri, using a range of tools specifically developed for this analysis. These reconstruction techniques enable the high-resolution rendering of global structure previously observed at lower resolution. Moreover, structures observed previously in small portions of the myometrium can be observed in the context of the whole organ. The reconstructions are in direct correspondence with the original histological slides, which allows the inspection of the anatomical context of any features identified in the three-dimensional reconstructions. Conclusions and significance The methods presented here have been used to generate a faithful representation of myometrial smooth muscle at a resolution of ∼50 μm per voxel edge. Characterisation of the smooth muscle structure of the myometrium by means of this technique revealed a detailed view of previously identified global structures in addition to a global view of the microarchitecture. A suite of visualisation tools allows researchers to interrogate the histological microarchitecture. These methods will be applicable to other smooth muscle tissues to analyse fibrous microarchitecture.
Collapse
Affiliation(s)
- E. Josiah Lutton
- Cell and Developmental Biology, Division of Biomedical Sciences Warwick Medical School, Coventry, United Kingdom
| | - Wim J. E. P. Lammers
- Bioengineering Institute, Auckland University, Auckland, New Zealand
- Department of Physiology, College of Medicine & Health Sciences, UAE University, Al Ain, United Arab Emirates
| | - Sean James
- Department of Pathology, University Hospitals Coventry and Warwickshire (UHCW), NHS Trust, Coventry, United Kingdom
| | | | - Andrew M. Blanks
- Cell and Developmental Biology, Division of Biomedical Sciences Warwick Medical School, Coventry, United Kingdom
- * E-mail:
| |
Collapse
|
34
|
Bribiesca-Contreras F, Sellers WI. Three-dimensional visualisation of the internal anatomy of the sparrowhawk ( Accipiter nisus) forelimb using contrast-enhanced micro-computed tomography. PeerJ 2017; 5:e3039. [PMID: 28316884 PMCID: PMC5356476 DOI: 10.7717/peerj.3039] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 01/27/2017] [Indexed: 12/20/2022] Open
Abstract
Background Gross dissection is a widespread method for studying animal anatomy, despite being highly destructive and time-consuming. X-ray computed tomography (CT) has been shown to be a non-destructive alternative for studying anatomical structures. However, in the past it has been limited to only being able to visualise mineralised tissues. In recent years, morphologists have started to use traditional X-ray contrast agents to allow the visualisation of soft tissue elements in the CT context. The aim of this project is to assess the ability of contrast-enhanced micro-CT (μCT) to construct a three-dimensional (3D) model of the musculoskeletal system of the bird wing and to quantify muscle geometry and any systematic changes due to shrinkage. We expect that this reconstruction can be used as an anatomical guide to the sparrowhawk wing musculature and form the basis of further biomechanical analysis of flight. Methods A 3% iodine-buffered formalin solution with a 25-day staining period was used to visualise the wing myology of the sparrowhawk (Accipiter nisus). μCT scans of the wing were taken over the staining period until full penetration of the forelimb musculature by iodine was reached. A 3D model was reconstructed by manually segmenting out the individual elements of the avian wing using 3D visualisation software. Results Different patterns of contrast were observed over the duration of the staining treatment with the best results occurring after 25 days of staining. Staining made it possible to visualise and identify different elements of the soft tissue of the wing. Finally, a 3D reconstruction of the musculoskeletal system of the sparrowhawk wing is presented and numerical data of muscle geometry is compared to values obtained by dissection. Discussion Contrast-enhanced μCT allows the visualisation and identification of the wing myology of birds, including the smaller muscles in the hand, and provides a non-destructive way for quantifying muscle volume with an accuracy of 96.2%. By combining contrast-enhanced μCT with 3D visualisation techniques, it is possible to study the individual muscles of the forelimb in their original position and 3D design, which can be the basis of further biomechanical analysis. Because the stain can be washed out post analysis, this technique provides a means of obtaining quantitative muscle data from museum specimens non-destructively.
Collapse
Affiliation(s)
| | - William I Sellers
- Faculty of Science and Engineering, University of Manchester , Manchester , UK
| |
Collapse
|
35
|
Extraction of the 3D local orientation of myocytes in human cardiac tissue using X-ray phase-contrast micro-tomography and multi-scale analysis. Med Image Anal 2017; 38:117-132. [PMID: 28334658 DOI: 10.1016/j.media.2017.02.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 02/06/2017] [Accepted: 02/13/2017] [Indexed: 11/23/2022]
Abstract
This paper presents a methodology to access the 3D local myocyte arrangements in fresh human post-mortem heart samples. We investigated the cardiac micro-structure at a high and isotropic resolution of 3.5 µm in three dimensions using X-ray phase micro-tomography at the European Synchrotron Radiation Facility. We then processed the reconstructed volumes to extract the 3D local orientation of the myocytes using a multi-scale approach with no segmentation. We created a simplified 3D model of tissue sample made of simulated myocytes with known size and orientations, to evaluate our orientation extraction method. Afterwards, we applied it to 2D histological cuts and to eight 3D left ventricular (LV) cardiac tissue samples. Then, the variation of the helix angles, from the endocardium to the epicardium, was computed at several spatial resolutions ranging from 3.63 mm3 to 1123 µm3. We measure an increased range of 20° to 30° from the coarsest resolution level to the finest level in the experimental samples. This result is in line with the higher values measured from histology. The displayed tractography demonstrates a rather smooth evolution of the transmural helix angle in six LV samples and a sudden discontinuity of the helix angle in two septum samples. These measurements bring a new vision of the human heart architecture from macro- to micro-scale.
Collapse
|
36
|
Enders C, Braig EM, Scherer K, Werner JU, Lang GK, Lang GE, Pfeiffer F, Noël P, Rummeny E, Herzen J. Advanced Non-Destructive Ocular Visualization Methods by Improved X-Ray Imaging Techniques. PLoS One 2017; 12:e0170633. [PMID: 28129364 PMCID: PMC5271321 DOI: 10.1371/journal.pone.0170633] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 01/06/2017] [Indexed: 01/15/2023] Open
Abstract
Due to limited X-ray contrast, the use of micro-CT in histology is so far not as widespread as predicted. While specific staining procedures-mostly using iodine-address this shortcoming, long diffusion times restrict its use in the often time-constrained daily routine. Recently, a novel staining protocol has been proposed using a biochemical preconditioning step, which increases the permeability of the cells for the staining agent. This could enable the imaging of entire organs of small mammals at a yet unmatched image quality with reasonable preparation and scan times. We here propose an adaptation of this technique for virtual ophthalmology and histology by volumetrically assessing both human and porcine eyes. Hereby, we demonstrate that (contrast-enhanced) micro-CT can outperform conventional histology in the assessment of tumor entities, as well as functioning as a supplementary tool for surgeons in the positioning of intraocular implants in-vitro and as a general assessment tool for ophthalmologic specimens.
Collapse
Affiliation(s)
- Christian Enders
- Department of Ophthalmology, University of Ulm, Prittwitzstrasse 43, 89075 Ulm, Germany
| | - Eva-Maria Braig
- Chair of Biomedical Physics, Departement of Physics and Institute of Medical Engineering (IMETUM), Technical University of Munich, James-Franck Strasse 1, 85748 Garching, Germany
- Department of Diagnostic and Interventionial Radiology, Technical University of Munich, Ismaninger Strasse 22, 81664 Munich, Germany
- * E-mail:
| | - Kai Scherer
- Chair of Biomedical Physics, Departement of Physics and Institute of Medical Engineering (IMETUM), Technical University of Munich, James-Franck Strasse 1, 85748 Garching, Germany
| | - Jens U. Werner
- Department of Ophthalmology, University of Ulm, Prittwitzstrasse 43, 89075 Ulm, Germany
| | - Gerhard K. Lang
- Department of Ophthalmology, University of Ulm, Prittwitzstrasse 43, 89075 Ulm, Germany
| | - Gabriele E. Lang
- Department of Ophthalmology, University of Ulm, Prittwitzstrasse 43, 89075 Ulm, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics, Departement of Physics and Institute of Medical Engineering (IMETUM), Technical University of Munich, James-Franck Strasse 1, 85748 Garching, Germany
- Department of Diagnostic and Interventionial Radiology, Technical University of Munich, Ismaninger Strasse 22, 81664 Munich, Germany
| | - Peter Noël
- Chair of Biomedical Physics, Departement of Physics and Institute of Medical Engineering (IMETUM), Technical University of Munich, James-Franck Strasse 1, 85748 Garching, Germany
- Department of Diagnostic and Interventionial Radiology, Technical University of Munich, Ismaninger Strasse 22, 81664 Munich, Germany
| | - Ernst Rummeny
- Department of Diagnostic and Interventionial Radiology, Technical University of Munich, Ismaninger Strasse 22, 81664 Munich, Germany
| | - Julia Herzen
- Chair of Biomedical Physics, Departement of Physics and Institute of Medical Engineering (IMETUM), Technical University of Munich, James-Franck Strasse 1, 85748 Garching, Germany
| |
Collapse
|
37
|
Pallua JD, Kuhn V, Pallua AF, Pfaller K, Pallua AK, Recheis W, Pöder R. Application of micro-computed tomography to microstructure studies of the medicinal fungus Hericium coralloides. Mycologia 2017; 107:227-38. [DOI: 10.3852/14-188] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Johannes D. Pallua
- Institute of Legal Medicine, Medical University of Innsbruck, Müllerstraβe 44, 6020 Innsbruck, Austria, and Institute of Microbiology, Leopold-Franzens University, Technikerstraβe 25, 6020 Innsbruck, Austria
| | - Volker Kuhn
- Department of Traumatology, Medical University of Innsbruck, Anichstraβe 35, 6020 Innsbruck, Austria
| | - Anton F. Pallua
- Section for Clinical Neurobiology, Medical University of Innsbruck, Anichstraβe 35, 6020 Innsbruck, Austria
| | - Kristian Pfaller
- Section for Histology and Embryology, Medical University of Innsbruck, Müllerstraβe 59, 6020 Innsbruck, Austria
| | - Anton K. Pallua
- Former Institute for Computed Tomography-Neuro CT, Medical University of Innsbruck, Anichstraβe 35, 6020 Innsbruck, Austria
| | - Wolfgang Recheis
- Department of Radiology, Medical University of Innsbruck, Anichstraβe 35, 6020 Innsbruck, Austria
| | - Reinhold Pöder
- Institute of Microbiology, Leopold-Franzens University, Technikerstraβe 25, 6020 Innsbruck, Austria
| |
Collapse
|
38
|
Varela M, Colman MA, Hancox JC, Aslanidi OV. Atrial Heterogeneity Generates Re-entrant Substrate during Atrial Fibrillation and Anti-arrhythmic Drug Action: Mechanistic Insights from Canine Atrial Models. PLoS Comput Biol 2016; 12:e1005245. [PMID: 27984585 PMCID: PMC5161306 DOI: 10.1371/journal.pcbi.1005245] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 11/12/2016] [Indexed: 12/31/2022] Open
Abstract
Anti-arrhythmic drug therapy is a frontline treatment for atrial fibrillation (AF), but its success rates are highly variable. This is due to incomplete understanding of the mechanisms of action of specific drugs on the atrial substrate at different stages of AF progression. We aimed to elucidate the role of cellular, tissue and organ level atrial heterogeneities in the generation of a re-entrant substrate during AF progression, and their modulation by the acute action of selected anti-arrhythmic drugs. To explore the complex cell-to-organ mechanisms, a detailed biophysical models of the entire 3D canine atria was developed. The model incorporated atrial geometry and fibre orientation from high-resolution micro-computed tomography, region-specific atrial cell electrophysiology and the effects of progressive AF-induced remodelling. The actions of multi-channel class III anti-arrhythmic agents vernakalant and amiodarone were introduced in the model by inhibiting appropriate ionic channel currents according to experimentally reported concentration-response relationships. AF was initiated by applied ectopic pacing in the pulmonary veins, which led to the generation of localized sustained re-entrant waves (rotors), followed by progressive wave breakdown and rotor multiplication in both atria. The simulated AF scenarios were in agreement with observations in canine models and patients. The 3D atrial simulations revealed that a re-entrant substrate was typically provided by tissue regions of high heterogeneity of action potential duration (APD). Amiodarone increased atrial APD and reduced APD heterogeneity and was more effective in terminating AF than vernakalant, which increased both APD and APD dispersion. In summary, the initiation and sustenance of rotors in AF is linked to atrial APD heterogeneity and APD reduction due to progressive remodelling. Our results suggest that anti-arrhythmic strategies that increase atrial APD without increasing its dispersion are effective in terminating AF. The mechanisms behind the most common arrhythmia, atrial fibrillation (AF), remain unclear and anti-arrhythmic drug therapy is often ineffective. In this paper, we develop and apply a novel comprehensive 3D model of canine atria to investigate the role of atrial heterogeneity in the mechanisms of AF and anti-arrhythmic drug action. We find that regions of high heterogeneity of action potential duration (APD) throughout the atria typically provide substrate for arrhythmogenic re-entrant waves during both AF initiation and progression. These mechanistic insights are directly linked with the efficacy of two clinically used class III anti-arrhythmic drugs: amiodarone is more effective at terminating AF than vernakalant, because it leads to an increase in atrial APD without increasing its dispersion. Our computational results are consistent with clinical observations and can help explain the superior efficacy of amiodarone in the clinical treatment of AF at late stages. This framework can easily be extended to investigate the action of other anti-arrhythmic drugs and translated to the human atria. By incorporating patient-specific anatomical and electrophysiological information, and after undergoing careful validation, the proposed in silico approach can become a useful tool to evaluate and potentially guide anti-arrhythmic therapy in the clinic.
Collapse
Affiliation(s)
- Marta Varela
- Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, United Kingdom
| | - Michael A. Colman
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Jules C. Hancox
- School of Physiology, Pharmacology and Neuroscience, Biomedical Sciences Building, University of Bristol, Bristol, United Kingdom
| | - Oleg V. Aslanidi
- Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King’s College London, London, United Kingdom
- * E-mail:
| |
Collapse
|
39
|
A Mathematical Spline-Based Model of Cardiac Left Ventricle Anatomy and Morphology. COMPUTATION 2016. [DOI: 10.3390/computation4040042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
40
|
Shearer T, Bradley RS, Hidalgo-Bastida LA, Sherratt MJ, Cartmell SH. Three-dimensional visualisation of soft biological structures by X-ray computed micro-tomography. J Cell Sci 2016; 129:2483-92. [PMID: 27278017 DOI: 10.1242/jcs.179077] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Whereas the two-dimensional (2D) visualisation of biological samples is routine, three-dimensional (3D) imaging remains a time-consuming and relatively specialised pursuit. Current commonly adopted techniques for characterising the 3D structure of non-calcified tissues and biomaterials include optical and electron microscopy of serial sections and sectioned block faces, and the visualisation of intact samples by confocal microscopy or electron tomography. As an alternative to these approaches, X-ray computed micro-tomography (microCT) can both rapidly image the internal 3D structure of macroscopic volumes at sub-micron resolutions and visualise dynamic changes in living tissues at a microsecond scale. In this Commentary, we discuss the history and current capabilities of microCT. To that end, we present four case studies to illustrate the ability of microCT to visualise and quantify: (1) pressure-induced changes in the internal structure of unstained rat arteries, (2) the differential morphology of stained collagen fascicles in tendon and ligament, (3) the development of Vanessa cardui chrysalises, and (4) the distribution of cells within a tissue-engineering construct. Future developments in detector design and the use of synchrotron X-ray sources might enable real-time 3D imaging of dynamically remodelling biological samples.
Collapse
Affiliation(s)
- Tom Shearer
- School of Materials, University of Manchester, Manchester M13 9PL, UK School of Mathematics, University of Manchester, Manchester M13 9PL, UK
| | - Robert S Bradley
- Henry Moseley X-ray Imaging Facility, School of Materials, University of Manchester, Manchester M13 9PL, UK
| | | | - Michael J Sherratt
- Institute of Inflammation and Repair, University of Manchester, Manchester M13 9PL, UK
| | - Sarah H Cartmell
- School of Materials, University of Manchester, Manchester M13 9PL, UK
| |
Collapse
|
41
|
Balint R, Lowe T, Shearer T. Optimal Contrast Agent Staining of Ligaments and Tendons for X-Ray Computed Tomography. PLoS One 2016; 11:e0153552. [PMID: 27078030 PMCID: PMC4831740 DOI: 10.1371/journal.pone.0153552] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 03/31/2016] [Indexed: 01/05/2023] Open
Abstract
X-ray computed tomography has become an important tool for studying the microstructures of biological soft tissues, such as ligaments and tendons. Due to the low X-ray attenuation of such tissues, chemical contrast agents are often necessary to enhance contrast during scanning. In this article, the effects of using three different contrast agents—iodine potassium iodide solution, phosphotungstic acid and phosphomolybdic acid—are evaluated and compared. Porcine anterior cruciate ligaments, patellar tendons, medial collateral ligaments and lateral collateral ligaments were used as the basis of the study. Three samples of each of the four ligament/tendon types were each assigned a different contrast agent (giving a total of twelve samples), and the progression of that agent through the tissue was monitored by performing a scan every day for a total period of five days (giving a total of sixty scans). Since the samples were unstained on day one, they had been stained for a total of four days by the time of the final scans. The relative contrast enhancement and tissue deformation were measured. It was observed that the iodine potassium iodide solution penetrated the samples fastest and caused the least sample shrinkage on average (although significant deformation was observed by the time of the final scans), whereas the phosphomolybdic acid caused the greatest sample shrinkage. Equations describing the observed behaviour of the contrast agents, which can be used to predict optimal staining times for ligament and tendon X-ray computed tomography, are presented.
Collapse
Affiliation(s)
- Richard Balint
- School of Materials, University of Manchester, Manchester, United Kingdom
| | - Tristan Lowe
- Henry Moseley X-ray Imaging Facility, School of Materials, University of Manchester, Manchester, United Kingdom
| | - Tom Shearer
- School of Materials, University of Manchester, Manchester, United Kingdom
- School of Mathematics, University of Manchester, Manchester, United Kingdom
- * E-mail:
| |
Collapse
|
42
|
Gignac PM, Kley NJ, Clarke JA, Colbert MW, Morhardt AC, Cerio D, Cost IN, Cox PG, Daza JD, Early CM, Echols MS, Henkelman RM, Herdina AN, Holliday CM, Li Z, Mahlow K, Merchant S, Müller J, Orsbon CP, Paluh DJ, Thies ML, Tsai HP, Witmer LM. Diffusible iodine-based contrast-enhanced computed tomography (diceCT): an emerging tool for rapid, high-resolution, 3-D imaging of metazoan soft tissues. J Anat 2016; 228:889-909. [PMID: 26970556 PMCID: PMC5341577 DOI: 10.1111/joa.12449] [Citation(s) in RCA: 295] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2016] [Indexed: 12/13/2022] Open
Abstract
Morphologists have historically had to rely on destructive procedures to visualize the three‐dimensional (3‐D) anatomy of animals. More recently, however, non‐destructive techniques have come to the forefront. These include X‐ray computed tomography (CT), which has been used most commonly to examine the mineralized, hard‐tissue anatomy of living and fossil metazoans. One relatively new and potentially transformative aspect of current CT‐based research is the use of chemical agents to render visible, and differentiate between, soft‐tissue structures in X‐ray images. Specifically, iodine has emerged as one of the most widely used of these contrast agents among animal morphologists due to its ease of handling, cost effectiveness, and differential affinities for major types of soft tissues. The rapid adoption of iodine‐based contrast agents has resulted in a proliferation of distinct specimen preparations and scanning parameter choices, as well as an increasing variety of imaging hardware and software preferences. Here we provide a critical review of the recent contributions to iodine‐based, contrast‐enhanced CT research to enable researchers just beginning to employ contrast enhancement to make sense of this complex new landscape of methodologies. We provide a detailed summary of recent case studies, assess factors that govern success at each step of the specimen storage, preparation, and imaging processes, and make recommendations for standardizing both techniques and reporting practices. Finally, we discuss potential cutting‐edge applications of diffusible iodine‐based contrast‐enhanced computed tomography (diceCT) and the issues that must still be overcome to facilitate the broader adoption of diceCT going forward.
Collapse
Affiliation(s)
- Paul M Gignac
- Department of Anatomy and Cell Biology, Oklahoma State University Center for Health Sciences, Tulsa, OK, USA
| | - Nathan J Kley
- Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY, USA
| | - Julia A Clarke
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA
| | - Matthew W Colbert
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA
| | | | - Donald Cerio
- Department of Biological Sciences, Ohio University, Athens, OH, USA
| | - Ian N Cost
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA
| | - Philip G Cox
- Department of Archaeology, University of York and Hull York Medical School, York, UK
| | - Juan D Daza
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, USA
| | | | | | - R Mark Henkelman
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - A Nele Herdina
- Department of Theoretical Biology, University of Vienna, Vienna, Austria
| | - Casey M Holliday
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA
| | - Zhiheng Li
- Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, TX, USA
| | - Kristin Mahlow
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätforschung an der Humboldt-Universität zu Berlin, Berlin, Germany
| | - Samer Merchant
- Department of Biomedical Engineering, The University of Utah, Salt Lake City, UT, USA
| | - Johannes Müller
- Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätforschung an der Humboldt-Universität zu Berlin, Berlin, Germany
| | - Courtney P Orsbon
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL, USA
| | - Daniel J Paluh
- Department of Biology, Villanova University, Villanova, PA, USA
| | - Monte L Thies
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, USA
| | - Henry P Tsai
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, MO, USA.,Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, USA
| | | |
Collapse
|
43
|
Jacquemet V. Lessons from computer simulations of ablation of atrial fibrillation. J Physiol 2016; 594:2417-30. [PMID: 26846178 DOI: 10.1113/jp271660] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 01/28/2016] [Indexed: 11/08/2022] Open
Abstract
This paper reviews the simulations of catheter ablation in computer models of the atria, from the first attempts to the most recent anatomical models. It describes how postulated substrates of atrial fibrillation can be incorporated into mathematical models, how modelling studies can be designed to test ablation strategies, what their current trade-offs and limitations are, and what clinically relevant lessons can be learnt from these simulations. Drawing a parallel between clinical and modelling studies, six ablation targets are considered: pulmonary vein isolation, linear ablation, ectopic foci, complex fractionated atrial electrogram, rotors and ganglionated plexi. The examples presented for each ablation target illustrate a major advantage of computer models, the ability to identify why a therapy is successful or not in a given atrial fibrillation substrate. The integration of pathophysiological data to create detailed models of arrhythmogenic substrates is expected to solidify the understanding of ablation mechanisms and to provide theoretical arguments supporting substrate-specific ablation strategies.
Collapse
Affiliation(s)
- Vincent Jacquemet
- Department of Molecular and Integrative Physiology, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada.,Centre de Recherche, Hôpital du Sacré-Cœur, Montréal, QC, Canada
| |
Collapse
|
44
|
Csepe TA, Zhao J, Hansen BJ, Li N, Sul LV, Lim P, Wang Y, Simonetti OP, Kilic A, Mohler PJ, Janssen PML, Fedorov VV. Human sinoatrial node structure: 3D microanatomy of sinoatrial conduction pathways. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 120:164-78. [PMID: 26743207 DOI: 10.1016/j.pbiomolbio.2015.12.011] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 12/10/2015] [Accepted: 12/18/2015] [Indexed: 01/09/2023]
Abstract
INTRODUCTION Despite a century of extensive study on the human sinoatrial node (SAN), the structure-to-function features of specialized SAN conduction pathways (SACP) are still unknown and debated. We report a new method for direct analysis of the SAN microstructure in optically-mapped human hearts with and without clinical history of SAN dysfunction. METHODS Two explanted donor human hearts were coronary-perfused and optically-mapped. Structural analyses of histological sections parallel to epicardium (∼13-21 μm intervals) were integrated with optical maps to create 3D computational reconstructions of the SAN complex. High-resolution fiber fields were obtained using 3D Eigen-analysis of the structure tensor, and used to analyze SACP microstructure with a fiber-tracking approach. RESULTS Optical mapping revealed normal SAN activation of the atria through a lateral SACP proximal to the crista terminalis in Heart #1 but persistent SAN exit block in diseased Heart #2. 3D structural analysis displayed a functionally-observed SAN border composed of fibrosis, fat, and/or discontinuous fibers between SAN and atria, which was only crossed by several branching myofiber tracts in SACP regions. Computational 3D fiber-tracking revealed that myofiber tracts of SACPs created continuous connections between SAN #1 and atria, but in SAN #2, SACP region myofiber tracts were discontinuous due to fibrosis and fat. CONCLUSIONS We developed a new integrative functional, structural and computational approach that allowed for the resolution of the specialized 3D microstructure of human SACPs for the first time. Application of this integrated approach will shed new light on the role of the specialized SAN microanatomy in maintaining sinus rhythm.
Collapse
Affiliation(s)
- Thomas A Csepe
- Department of Physiology & Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Jichao Zhao
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Brian J Hansen
- Department of Physiology & Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Ning Li
- Department of Physiology & Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Lidiya V Sul
- Department of Physiology & Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Praise Lim
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Yufeng Wang
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Orlando P Simonetti
- Department of Biomedical Informatics, College of Medicine, The Ohio State University, Columbus, OH, USA; Davis Heart & Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Ahmet Kilic
- Davis Heart & Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Department of Surgery, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Peter J Mohler
- Department of Physiology & Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Davis Heart & Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Paul M L Janssen
- Department of Physiology & Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Davis Heart & Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Vadim V Fedorov
- Department of Physiology & Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Davis Heart & Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
| |
Collapse
|
45
|
Dibb K, Trafford A, Zhang H, Eisner D. A model model: a commentary on DiFrancesco and Noble (1985) 'A model of cardiac electrical activity incorporating ionic pumps and concentration changes'. Philos Trans R Soc Lond B Biol Sci 2015; 370:rstb.2014.0316. [PMID: 25750236 PMCID: PMC4360121 DOI: 10.1098/rstb.2014.0316] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
This paper summarizes the advances made by the DiFrancesco and Noble (DFN) model of cardiac cellular electrophysiology, which was published in Philosophical Transactions B in 1985. This model was developed at a time when the introduction of new techniques and provision of experimental data had resulted in an explosion of knowledge about the cellular and biophysical properties of the heart. It advanced the cardiac modelling field from a period when computer models considered only the voltage-dependent channels in the surface membrane. In particular, it included a consideration of changes of both intra- and extracellular ionic concentrations. In this paper, we summarize the most important contributions of the DiFrancesco and Noble paper. We also describe how computer modelling has developed subsequently with the extension from the single cell to the whole heart as well as its use in understanding disease and predicting the effects of pharmaceutical interventions. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society.
Collapse
Affiliation(s)
- Katharine Dibb
- Institute for Cardiovascular Sciences, University of Manchester, Manchester, UK
| | - Andrew Trafford
- Institute for Cardiovascular Sciences, University of Manchester, Manchester, UK
| | - Henggui Zhang
- Computational Biology, Biological Physics Group, School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - David Eisner
- Institute for Cardiovascular Sciences, University of Manchester, Manchester, UK
| |
Collapse
|
46
|
Stephenson RS, Agger P, Lunkenheimer PP, Zhao J, Smerup M, Niederer P, Anderson RH, Jarvis JC. The functional architecture of skeletal compared to cardiac musculature: Myocyte orientation, lamellar unit morphology, and the helical ventricular myocardial band. Clin Anat 2015; 29:316-32. [PMID: 26478993 DOI: 10.1002/ca.22661] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 10/13/2015] [Accepted: 10/15/2015] [Indexed: 11/06/2022]
Abstract
How the cardiomyocytes are aggregated within the heart walls remains contentious. We still do not fully understand how the end-to-end longitudinal myocytic chains are arranged, nor the true extent and shape of the lamellar units they aggregate to form. In this article, we show that an understanding of the complex arrangement of cardiac musculature requires knowledge of three-dimensional myocyte orientation (helical and intrusion angle), and appreciation of myocyte packing within the connective tissue matrix. We show how visualization and segmentation of high-resolution three-dimensional image data can accurately identify the morphology and orientation of the myocytic chains, and the lamellar units. Some maintain that the ventricles can be unwrapped in the form of a "helical ventricular myocardial band," that is, as a compartmentalized band with selective regional innervation and deformation, and a defined origin and insertion like most skeletal muscles. In contrast to the simpler interpretation of the helical ventricular myocardial band, we provide insight as to how the complex myocytic chains, the heterogeneous lamellar units, and connective tissue matrix form an interconnected meshwork, which facilitates the complex internal deformations of the ventricular wall. We highlight the dangers of disregarding the intruding cardiomyocytes. Preparation of the band destroys intruding myocytic chains, and thus disregards the functional implications of the antagonistic auxotonic forces they produce. We conclude that the ventricular myocardium is not analogous to skeletal muscle, but is a complex three-dimensional meshwork, with a heterogeneous branching lamellar architecture.
Collapse
Affiliation(s)
- Robert S Stephenson
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, United Kingdom
| | - Peter Agger
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Paul P Lunkenheimer
- Department of Experimental Thoracic and Cardiovascular Surgery, University Hospital Munster, Munster, DE, Germany
| | - Jichao Zhao
- Auckland Bioengineering Institute, The University of Auckland, Auckland, New Zealand
| | - Morten Smerup
- Department of Cardiothoracic & Vascular Surgery, Aarhus University, Aarhus, Denmark
| | - Peter Niederer
- Institute for Biomedical Engineering, University of Zurich, Zurich, CH, Switzerland
| | - Robert H Anderson
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.,Division of Biomedical Sciences, University College London, London, United Kingdom
| | - Jonathan C Jarvis
- Research Institute for Sport and Exercise Science, Liverpool John Moores University, Liverpool, United Kingdom
| |
Collapse
|
47
|
Ferrer A, Sebastián R, Sánchez-Quintana D, Rodríguez JF, Godoy EJ, Martínez L, Saiz J. Detailed Anatomical and Electrophysiological Models of Human Atria and Torso for the Simulation of Atrial Activation. PLoS One 2015; 10:e0141573. [PMID: 26523732 PMCID: PMC4629897 DOI: 10.1371/journal.pone.0141573] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 10/09/2015] [Indexed: 01/24/2023] Open
Abstract
Atrial arrhythmias, and specifically atrial fibrillation (AF), induce rapid and irregular activation patterns that appear on the torso surface as abnormal P-waves in electrocardiograms and body surface potential maps (BSPM). In recent years both P-waves and the BSPM have been used to identify the mechanisms underlying AF, such as localizing ectopic foci or high-frequency rotors. However, the relationship between the activation of the different areas of the atria and the characteristics of the BSPM and P-wave signals are still far from being completely understood. In this work we developed a multi-scale framework, which combines a highly-detailed 3D atrial model and a torso model to study the relationship between atrial activation and surface signals in sinus rhythm. Using this multi scale model, it was revealed that the best places for recording P-waves are the frontal upper right and the frontal and rear left quadrants of the torso. Our results also suggest that only nine regions (of the twenty-one structures in which the atrial surface was divided) make a significant contribution to the BSPM and determine the main P-wave characteristics.
Collapse
Affiliation(s)
- Ana Ferrer
- Centro de Investigación e Innovación en Bioingeniería (Ci2B), Universitat Politècnica de València, Valencia, Spain
- * E-mail:
| | - Rafael Sebastián
- Computational Multiscale Physiology Lab (CoMMLab), Department of Computer Science, Universitat de Valencia, Valencia, Spain
| | - Damián Sánchez-Quintana
- Department of Anatomy and Cell Biology, Faculty of Medicine, Universidad de Extremadura, Badajoz, Spain
| | - José F. Rodríguez
- Applied Mechanics and Bioengineering Group (AMB), Universidad de Zaragoza, Zaragoza, Spain, and Dipartimento di Chimica, Materiali e Ingegneria Chimica “Giulio Natta”, Politecnico di Milano, Milano, Italy
| | - Eduardo J. Godoy
- Centro de Investigación e Innovación en Bioingeniería (Ci2B), Universitat Politècnica de València, Valencia, Spain
| | - Laura Martínez
- Centro de Investigación e Innovación en Bioingeniería (Ci2B), Universitat Politècnica de València, Valencia, Spain
| | - Javier Saiz
- Centro de Investigación e Innovación en Bioingeniería (Ci2B), Universitat Politècnica de València, Valencia, Spain
| |
Collapse
|
48
|
Nikolaidou T, Cai XJ, Stephenson RS, Yanni J, Lowe T, Atkinson AJ, Jones CB, Sardar R, Corno AF, Dobrzynski H, Withers PJ, Jarvis JC, Hart G, Boyett MR. Congestive Heart Failure Leads to Prolongation of the PR Interval and Atrioventricular Junction Enlargement and Ion Channel Remodelling in the Rabbit. PLoS One 2015; 10:e0141452. [PMID: 26509807 PMCID: PMC4624927 DOI: 10.1371/journal.pone.0141452] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 10/08/2015] [Indexed: 01/31/2023] Open
Abstract
Heart failure is a major killer worldwide. Atrioventricular conduction block is common in heart failure; it is associated with worse outcomes and can lead to syncope and bradycardic death. We examine the effect of heart failure on anatomical and ion channel remodelling in the rabbit atrioventricular junction (AVJ). Heart failure was induced in New Zealand rabbits by disruption of the aortic valve and banding of the abdominal aorta resulting in volume and pressure overload. Laser micro-dissection and real-time polymerase chain reaction (RT-PCR) were employed to investigate the effects of heart failure on ion channel remodelling in four regions of the rabbit AVJ and in septal tissues. Investigation of the AVJ anatomy was performed using micro-computed tomography (micro-CT). Heart failure animals developed first degree heart block. Heart failure caused ventricular myocardial volume increase with a 35% elongation of the AVJ. There was downregulation of HCN1 and Cx43 mRNA transcripts across all regions and downregulation of Cav1.3 in the transitional tissue. Cx40 mRNA was significantly downregulated in the atrial septum and AVJ tissues but not in the ventricular septum. mRNA abundance for ANP, CLCN2 and Navβ1 was increased with heart failure; Nav1.1 was increased in the inferior nodal extension/compact node area. Heart failure in the rabbit leads to prolongation of the PR interval and this is accompanied by downregulation of HCN1, Cav1.3, Cx40 and Cx43 mRNAs and anatomical enlargement of the entire heart and AVJ.
Collapse
Affiliation(s)
- Theodora Nikolaidou
- Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
- * E-mail:
| | - Xue J. Cai
- Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Robert S. Stephenson
- School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Joseph Yanni
- Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Tristan Lowe
- The Manchester Henry Moseley X-ray Imaging Facility, University of Manchester, Manchester, United Kingdom
| | - Andrew J. Atkinson
- Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Caroline B. Jones
- Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Rida Sardar
- Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Antonio F. Corno
- School of Medical Sciences, Health Campus, University Sains Malaysia, Kubang Kerian, Malaysia
| | - Halina Dobrzynski
- Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Philip J. Withers
- The Manchester Henry Moseley X-ray Imaging Facility, University of Manchester, Manchester, United Kingdom
| | - Jonathan C. Jarvis
- School of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - George Hart
- Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Mark R. Boyett
- Institute of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| |
Collapse
|
49
|
Three-dimensional non-destructive soft-tissue visualization with X-ray staining micro-tomography. Sci Rep 2015; 5:14088. [PMID: 26404036 PMCID: PMC4585898 DOI: 10.1038/srep14088] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 08/18/2015] [Indexed: 01/30/2023] Open
Abstract
Low inherent contrast in soft tissues has been limiting the use of X-ray absorption micro-computed tomography (micro-CT) to access high-resolution structural information of animal organs. The staining agents used in micro-CT to improve the contrast fail in providing high-quality images of whole organs of animals due to diffusion problems of the staining agent into the sample. We demonstrate a staining protocol that incorporates a biochemical conditioning step prior to exposure to the staining agent that succeeds in overcoming the diffusion problems, thus quickly providing high-quality micro-CT images of whole organs of mammals. Besides of yielding non-distorted three-dimensional information at the same spatial resolution accessible in histological sections, micro-CT images of whole organs stained by our method enable easy screening of slices along any direction of the volume thus demonstrating new possibilities of structural analysis in biomedical science.
Collapse
|
50
|
Burton RAB, Lee P, Casero R, Garny A, Siedlecka U, Schneider JE, Kohl P, Grau V. Three-dimensional histology: tools and application to quantitative assessment of cell-type distribution in rabbit heart. Europace 2015; 16 Suppl 4:iv86-iv95. [PMID: 25362175 PMCID: PMC4217519 DOI: 10.1093/europace/euu234] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Aims Cardiac histo-anatomical organization is a major determinant of function. Changes in tissue structure are a relevant factor in normal and disease development, and form targets of therapeutic interventions. The purpose of this study was to test tools aimed to allow quantitative assessment of cell-type distribution from large histology and magnetic resonance imaging- (MRI) based datasets. Methods and results Rabbit heart fixation during cardioplegic arrest and MRI were followed by serial sectioning of the whole heart and light-microscopic imaging of trichrome-stained tissue. Segmentation techniques developed specifically for this project were applied to segment myocardial tissue in the MRI and histology datasets. In addition, histology slices were segmented into myocytes, connective tissue, and undefined. A bounding surface, containing the whole heart, was established for both MRI and histology. Volumes contained in the bounding surface (called ‘anatomical volume’), as well as that identified as containing any of the above tissue categories (called ‘morphological volume’), were calculated. The anatomical volume was 7.8 cm3 in MRI, and this reduced to 4.9 cm3 after histological processing, representing an ‘anatomical’ shrinkage by 37.2%. The morphological volume decreased by 48% between MRI and histology, highlighting the presence of additional tissue-level shrinkage (e.g. an increase in interstitial cleft space). The ratio of pixels classified as containing myocytes to pixels identified as non-myocytes was roughly 6:1 (61.6 vs. 9.8%; the remaining fraction of 28.6% was ‘undefined’). Conclusion Qualitative and quantitative differentiation between myocytes and connective tissue, using state-of-the-art high-resolution serial histology techniques, allows identification of cell-type distribution in whole-heart datasets. Comparison with MRI illustrates a pronounced reduction in anatomical and morphological volumes during histology processing.
Collapse
Affiliation(s)
- Rebecca A B Burton
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK
| | - Peter Lee
- Department of Physics, University of Oxford, Oxford OX1 3RH, UK
| | - Ramón Casero
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX3 7DQ, UK
| | - Alan Garny
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK
| | - Urszula Siedlecka
- The Heart Science Centre, National Heart and Lung Institute, Imperial College London, Harefield UB9 6JH, UK
| | - Jürgen E Schneider
- British Heart Foundation Experimental MR Unit, Radcliffe Department of Medicine, Division of Cardiovascular Medicine, University of Oxford, Oxford OX3 7BN, UK
| | - Peter Kohl
- The Heart Science Centre, National Heart and Lung Institute, Imperial College London, Harefield UB9 6JH, UK
| | - Vicente Grau
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford OX3 7DQ, UK
| |
Collapse
|