Download or read book Non invasive Characterization of the Mechanical Properties of Arteries written by Yanik Tardy and published by . This book was released on 1992 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mechanical Properties of Arteries written by Jan-Lucas Gade and published by Linköping University Electronic Press. This book was released on 2019-08-29 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this Licentiate of Engineering thesis, a method is proposed that identi?es the mechanical properties of arteries in vivo. The mechanical properties of an artery are linked to the development of cardiovascular diseases. The possibility to identify the mechanical properties of an artery inside the human body could, thus, facilitate disease diagnostization, treatment and monitoring. Supplied with information obtainable in the clinic, typically limited to time- resolved pressure-radius measurement pairs, the proposed in vivo parameter identi- ?cation method calculates six representative parameters by solving a minimization problem. The artery is treated as a homogeneous, incompressible, residual stress- free, thin-walled tube consisting of an elastin dominated matrix with embedded collagen ?bers referred to as the constitutive membrane model. To validate the in vivo parameter identi?cation method, in silico arteries in the form of ?nite element models are created using published data for the human abdominal aorta. With these in silico arteries which serve as mock experiments with pre-de?ned material parameters and boundary conditions, in vivo-like pressure-radius data sets are generated. The mechanical properties of the in silico arteries are then determined using the proposed parameter identi?cation method. By comparing the identi?ed and the pre-de?ned parameters, the identi?cation method is quantitatively validated. The parameters for the radius of the stress-free state and the material constant associated with elastin show high agreement in case of healthy arteries. Larger di?erences are obtained for the material constants associated with collagen, and the largest discrepancy occurs for the in situ axial prestretch. For arteries with a pathologically small elastin content, incorrect parameters are identi?ed but the presence of a diseased artery is revealed by the parameter identi?cation method. Furthermore, the identi?ed parameters are used in the constitutive membrane model to predict the stress state of the artery in question. The stress state is thereby decomposed into an isotropic and an anisotropic component which are primarily associated with the elastin dominated matrix and the collagen ?bers, respectively. In order to assess the accuracy of the predicted stress, it is compared to the known stress state of the in silico arteries. The comparison of the predicted and the in silico decomposed stress states show a close agreement for arteries exhibiting a low transmural stress gradient. With increasing transmural stress gradient the agreement deteriorates. The proposed in vivo parameter identi?cation method is capable of identifying adequate parameters and predicting the decomposed stress state reasonably well for healthy human abdominal aortas from in vivo-like data. In diesem Lizentiat der Ingenieurwissenschaften wird eine Methode zur Identifikation der mechanischen Eigenschaften von Arterien in vivo vorgestellt. Die mechanischen Eigenschaften einer Arterie sind mit der Ausbildung kardiovaskulärer Krankheiten verknüpft und deren Identifikation hat daher das Potenzial die Diagnose, die Behandlung und die Überwachung dieser Krankheiten zu verbessern. Basierend auf klinisch möglichen Messungen, die üblicherweise auf ein zeitaufgelöstes Druck-Radiussignal limitiert sind, werden sechs repräsentative Parameter durch Lösen eines Minimierungsproblems berechnet. Die sechs Parameter sind dabei die Eingangsparameter des zur Hilfe gezogenen konstitutiven Schalenmodells welches eine Arterie als eine homogene, inkompressible, restspannungsfreie und dünnwandige Röhre beschreibt. Weiterhin wird angenommen, dass die Arterienwand aus einer elastindominierten Matrix mit eingebetteten Kollagenfasern besteht. Um die in vivo Parameteridentifikationsmethode zu validieren, werden in silico Arterien in Form von Finite Elemente Modellen erstellt. Diese in silico Arterien beruhen auf publizierten Materialparametern der menschlichen Abdominalaorta und dienen als Pseudoexperimente mit vordefinierten mechanischen Eigenschaften und Randbedingungen. Mit diesen Arterien werden in vivo-ähnliche Druck-Radiussignale erstellt und anschliesend werden ihre mechanischen Eigenschaften mit Hilfe der Parameteridentifikationsmethode bestimmt. Der Vergleich der identifizierten und der vordefinierten Parameter ermöglicht die quantitative Validierung der Methode. Die Parameter des spannungsfreien Radius und der Materialkonstanten für Elastin weisen hohe Übereinstummung im Falle gesunder Arterien auf. Die Abweichung der Materialkonstanten für Kollagen sind etwas gröser und der gröste Unterschied tritt beim axialen in situ Stretch auf. Für Arterien mit einem pathologisch geringen Elastinbestandteil werden falsche Parameter identifiziert, wobei die Parameteridentifikationsmethode eine krankhafte Arterie offenlegt. Weiterhin werden mit Hilfe der identifizierten Parameter und des konstitutiven Schalenmodells der Spannungszustand in der Arterienwand berechnet. Dieser ist dabei aufgeteilt in einen isotropen und einen anisotropen Anteil. Der isotrope Anteil wird mit der elastindomierten Matrix und der anisotrope Anteil mit den Kollagenfasern verknüpft. Um die Genauigkeit des berechneten Spannungszustandes beurteilen zu können, wird dieser mit dem Zustand in den in silico Arterien verglichen. Im Fall von Arterien, die einen geringen transmuralen Spannungsgradienten aufweisen, entspricht der berechnete Spannungszustand dem in silico Zustand. Mit zunehmendem transmuralen Spannungsgradienten lässt die Übereinstimmung nach. Für die gesunde menschliche Abdominalaorta ist die entwickelte in vivo Parameteridentifikationsmethode in der Lage, basierend auf in vivo-ähnlichen Messsignalen, adäquate Parameter zu identifizieren und einen zufriedenstellenden Spannungszustand zu berechnen. I denna licentiatavhandling föreslås en metod för att identifiera mekaniska egenskaper hos artärer in vivo. De mekaniska egenskaperna är kopplade till utvecklingen av hjärt-kärlsjukdomar, och möjligheten att identifiera dessa egenskaper skulle således kunna underlätta diagnostisering, behandling och uppföljning av dessa sjukdomar. Den förslagna metoden använder kliniskt mätbara tryck-radie-signaler och löser ett minimeringsproblem för att bestämma sex parametrar som beskriver kärlets mekaniska egenskaper. Artären modelleras som ett homogent, inkompressibelt och spänningsfritt tunnväggigt rör där kärlväggen utgörs av en elastindominerad matris armerad med inbäddade kollagenfibrer. För att validera parameteridentifieringen skapas en uppsättning representativa, virtuella artärer med hjälp av finita element. Dessa in silico-artärer baseras på publicerade data för mänsklig bukaorta och används för att generera fiktiva tryckradie-signaler vilka sedan matas in i den förslagna modellen. Genom att parametrar och randvillkor för in silico-artärerna är kända fungerar dessa som en kontroll mot vilka resultatet från parameteridentifieringen kan jämföras. Parametrarna som beskriver den icke trycksatta radien och den elastindominerade matrisen visar god överensstämmelse med de in silico-artärerna för friska kärl. Större diskrepans erhålls för de parametrar som associeras med kollagenet, och den största avvikelsen erhålls för den parameter som beskriver den axiella försträckningen. För artärer med patologiskt lågt elastininnehåll identifieras felaktiga parametrar, men resultatet avslöjar ändå tydligt en sjuk artär. De identifierade parametrarna har också använts för att jämföra spänningstillst åndet i membranmodellen och in silico-artäreren. Spänningstillståndet har delats upp i en isotrop och en anisotrop komponent svarande mot, i huvudsak, den elastindominerade matrisen samt kollagenfibrerna. Resultatet visar en mycket god överensstämmelse för bägge komponenterna hos in silico-artärer med låg spänningsgradient genom väggen. Med ökande spänningsgradient försämras dock överensstämmelsen. Resultatet visar att den förslagna metoden är kapabel att identifiera adekvata parametrar och att förutsäga spänningskomponenterna i en frisk aorta.

Download or read book Atherosclerotic Plaque Characterization Methods Based on Coronary Imaging written by Lambros S Athanasiou and published by Academic Press. This book was released on 2017-05-04 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atherosclerotic Plaque Characterization Methods Based on Coronary Imaging provides a complete review of computer methods for atherosclerotic plaque reconstruction and characterization. The authors, with their expertise from biomedical engineering, computer science, and cardiology, offer a holistic view. The focus of the book is on the presentation of major imaging techniques, including their limitations. It includes details on the mechanical characterization and properties of plaques and appropriate constitutive models to describe the mechanical behavior of plaques. The authors explore the challenges of using multiple coronary imaging technologies, and provide the pros and cons of invasive vs. non-invasive techniques. Methods for plaque characterization and 3D reconstruction of coronary arteries using IVUS, OCT, and CT images are described. This book will help readers study new trends in image processing analysis and plaque characterization, implement automated plaque characterization methodologies, understand coronary imaging drawbacks, and comprehend 3 dimensional coronary artery and plaque reconstruction methods. Describes the multimodality imaging techniques that are commonly used in the diagnosis of arterial diseases, including intravascular ultrasound, optical coherence tomography, angiography, computed tomography angiography, and magnetic resonance angiography Discusses in-depth the computational methods which can be used for the detection of different plaque types Explores plaque in 3D reconstruction methods and plaque modeling approaches

Download or read book Biological Flows written by Colin G. Caro and published by Springer. This book was released on 2013-12-19 with total page 369 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biomechanics has a distinguished history extending at least to the 16th Century. However the later half oftbis century has seen an explosion ofthe field with it being viewed as affering exciting challenges for physical scientists and engineers interested in the life sciences, and wonderful opportunities for life scientists eager to collaborate with physical scientists and engineers and to render their scientific work more fundamental. That the field is now weil established and expanding is demonstrated by the formation of a World Committee for Biomechanics and the success and large participation in the 1st and 2nd World Congresses of Biomechanics, held respectively in San Diego in 1990 and in Amsterdam in 1994. With more than 1350 scientific papers delivered at the 2nd World Congress, either within symposia or oral or poster sessions, it would have been out of the question to try to produce comprehensive edited proceedings. Moreover, we are confident that most of the papers have been or will be published in one ofthe excellentjoumals covering the field. But of effort contributed by the plenary lecturers and the tutorial we thought that the large amount and keynote speakers of various symposia deserved tobe recognised in the form of a specific publication, thus also allowing those unable to attend the presentatiops . . tC\ sh?r~ in the findings. Furthermore, we feel that there is now a need to review aspects 'oftlie freld.

Download or read book Biomechanics of Soft Tissue in Cardiovascular Systems written by Gerhard A. Holzapfel and published by Springer. This book was released on 2014-05-04 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is written by leading experts in the field presenting an up-to-date view of the subject matter in a didactically sound manner. It presents a review of the current knowledge of the behaviour of soft tissues in the cardiovascular system under mechanical loads, and the importance of constitutive laws in understanding the underlying mechanics is highlighted. Cells are also described together with arteries, tendons and ligaments, heart, and other biological tissues of current research interest in biomechanics. This includes experimental, continuum mechanical and computational perspectives, with the emphasis on nonlinear behaviour, and the simulation of mechanical procedures such as balloon angioplasty.

Download or read book Subject Index of Current Research Grants and Contracts Administered by the National Heart Lung and Blood Institute written by National Heart, Lung, and Blood Institute and published by . This book was released on 1979 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ultrasound Elastography for Biomedical Applications and Medicine written by Ivan Z. Nenadic and published by John Wiley & Sons. This book was released on 2018-10-25 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultrasound Elastography for Biomedical Applications and Medicine Ivan Z. Nenadic, Matthew W. Urban, James F. Greenleaf, Mayo Clinic Ultrasound Research Laboratory, Mayo Clinic College of Medicine, USA Jean-Luc Gennisson, Miguel Bernal, Mickael Tanter, Institut Langevin – Ondes et Images, ESPCI ParisTech CNRS, France Covers all major developments and techniques of Ultrasound Elastography and biomedical applications The field of ultrasound elastography has developed various techniques with the potential to diagnose and track the progression of diseases such as breast and thyroid cancer, liver and kidney fibrosis, congestive heart failure, and atherosclerosis. Having emerged in the last decade, ultrasound elastography is a medical imaging modality that can noninvasively measure and map the elastic and viscous properties of soft tissues. Ultrasound Elastography for Biomedical Applications and Medicine covers the basic physics of ultrasound wave propagation and the interaction of ultrasound with various media. The book introduces tissue elastography, covers the history of the field, details the various methods that have been developed by research groups across the world, and describes its novel applications, particularly in shear wave elastography. Key features: Covers all major developments and techniques of ultrasound elastography and biomedical applications. Contributions from the pioneers of the field secure the most complete coverage of ultrasound elastography available. The book is essential reading for researchers and engineers working in ultrasound and elastography, as well as biomedical engineering students and those working in the field of biomechanics.

Download or read book Innovative Developments in Multi Modality Elastography written by Simon Chatelin and published by Frontiers Media SA. This book was released on 2022-11-23 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Cardiovascular Mechanics written by Michel R. Labrosse and published by CRC Press. This book was released on 2018-09-13 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this book is to illustrate in specific detail how cardiovascular mechanics stands as a common pillar supporting such different clinical successes as drugs for high blood pressure, prosthetic heart valves and coronary artery bypass grafting, among others. This information is conveyed through a comprehensive treatment of the overarching principles and theories that are behind mechanobiological processes, aortic and arterial mechanics, atherosclerosis, blood and microcirculation, hear valve mechanics, as well as medical devices and drugs. Examines all major theoretical and practical aspects of mechanical forces related to the cardiovascular system. Discusses a unique coverage of mechanical changes related to an aging cardiovascular system. Provides an overview of experimental methods in cardiovascular mechanics. Written by world-class researchers from Canada, the US and EU. Extensive references are provided at the end of each chapter to enhance further study. Michel R. Labrosse is the founder of the Cardiovascular Mechanics Laboratory at the University of Ottawa, where he is a full professor within the Department of Mechanical Engineering. He has been an active researcher in academia along with being heavily associated with the University of Ottawa Heart Institute. He has authored or co-authored over 90 refereed communications, and supervised or co-supervised over 40 graduate students and post-docs.

Download or read book An Experimental Method for Measuring written by and published by DIANE Publishing. This book was released on with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Biology of the Arterial Wall written by Bernard I. Levy and published by Springer Science & Business Media. This book was released on 2007-11-23 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biology of the Arterial Wall is intended as a general reference text concerned with the biology of the vascular cells and the blood vessel wall under physiological and pathological conditions. One of the major functions of the arteries is to maintain a continuous blood flow to the organs whatever the pressure conditions, thanks to the vasomotor tone of the smooth muscle cells. Great advances have been made over the last decade in the understanding of the endothelial cells as integrators and transducers of signals originating from the blood stream. The pluripotent control functions of the endothelial cells in the vessel wall are now well recognized. A review of endothelial functions and dysfunctions is presented. Cell biology and molecular genetic studies have now identified an array of molecules elaborated by endothelial cells and vascular smooth muscle cells and by the blood-borne elements which interact with artery cells, defending the artery against injury and modulating evolving abnormal processes. Molecules which induce or inhibit endothelial and/or smooth muscle cells are currently under great scrutiny. Angiogenesis, which plays a major role in tumor growth, but may also be beneficial as a healing process in muscle ischemia, is discussed. Apoptosis, or programmed cell death, has only recently been recognized as an essential process in blood vessel modeling and remodeling. An overview of apoptosis in the vascular system is presented. It is increasingly evident that the adjustments of the blood vessel wall are made in the presence of deforming disease processes such as hypertension and atherosclerosis. The second part of the book is concerned with the blood vessel wall in disease conditions. Several chapters review the role of the vessel and vascular cells in inflammation, and vascular remodeling during arterial hypertension and aging. One chapter is devoted to atherogenesis, atheroma and plaque instability, followed by the pathophysiology of post-angioplasty restenosis, which is a crucial issue in modern interventional cardiology.

Download or read book Ultrasound and Carotid Bifurcation Atherosclerosis written by Andrew Nicolaides and published by Springer Science & Business Media. This book was released on 2011-11-24 with total page 641 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ultrasound and Carotid Bifurcation Atherosclerosis provides a comprehensive overview of the most recent advancements in instrumentation, imaging techniques including the use of contrast enhancement agents, plaque image analysis and its automation, elastography and plaque motion analysis; also, the use of ultrasonic and other biomarkers in the detection of the high risk cardiovascular individual. Finally, it deals with the application of IVUS, TCD and carotid plaque characterization in clinical practice and in stroke risk stratification. Ultrasound and Carotid Bifurcation Atherosclerosis is intended for all those working in the field of atherosclerosis, ultrasound imaging and cardiovascular risk, including the clinician, the vascular ultrasonographer, the epidemiologist, the molecular biologist, the biomedical engineer and the informatics scientist. Furthermore, this book bridges the gap between the researcher and the clinician, who is keen to incorporate the latest results of research to his daily practice.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1987 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Research Awards Index written by and published by . This book was released on 1980 with total page 1230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Basic Sciences for MCEM written by Chetan Trivedy and published by CRC Press. This book was released on 2016-05-15 with total page 771 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a dedicated resource for those sitting the Part A of the MCEM (Membership of the College of Emergency Medicine) examination. It forms an essential revision guide for emergency trainees who need to acquire a broad understanding of the basic sciences, which underpin their approach to clinical problems in the emergency department. Common clinical scenarios are used to highlight the essential underlying basic science principles, providing a link between clinical management and a knowledge of the underlying anatomical, physiological, pathological and biochemical processes. Multiple choice questions with reasoned answers are used to confirm the candidates understanding and for self testing. Unlike other recent revision books which provide MCQ questions with extended answers, this book uses clinical cases linked to the most recent basic science aspects of the CEM syllabus to provide a book that not only serves as a useful revision resource for the Part A component of the MCEM examination, but also a unique way of understanding the processes underlying common clinical cases seen every day in the emergency department. This book is essential for trainees sitting the Part A of the MCEM exam and for clinicians and medical students who need to refresh their knowledge of basic sciences relevant to the management of clinical emergencies.

Download or read book Emerging Methods in Non invasive Vascular Imaging written by Luca Biasiolli and published by Frontiers Media SA. This book was released on 2022-12-05 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computing and Visualization for Intravascular Imaging and Computer Assisted Stenting written by Simone Balocco and published by Academic Press. This book was released on 2016-12-12 with total page 480 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computing and Visualization for Intravascular Imaging and Computer-Assisted Stenting presents imaging, treatment, and computed assisted technological techniques for diagnostic and intraoperative vascular imaging and stenting. These techniques offer increasingly useful information on vascular anatomy and function, and are poised to have a dramatic impact on the diagnosis, analysis, modeling, and treatment of vascular diseases. After setting out the technical and clinical challenges of vascular imaging and stenting, the book gives a concise overview of the basics before presenting state-of-the-art methods for solving these challenges. Readers will learn about the main challenges in endovascular procedures, along with new applications of intravascular imaging and the latest advances in computer assisted stenting. Brings together scientific researchers, medical experts, and industry partners working in different anatomical regions Presents an introduction to the clinical workflow and current challenges in endovascular Interventions Provides a review of the state-of-the-art methodologies in endovascular imaging and their applications Poses outstanding questions and discusses future research