Download or read book Noninvasive Imaging of Hemorrhagic Myocardial Infarction with Confounder Corrected T2 Cardiac MRI written by Xingmin Guan and published by . This book was released on 2022 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current gold-standard approach for detection and quantification of intramyocardial hemorrhage (IMH) is T2* cardiovascular magnetic resonance imaging (CMR). T2*-based imaging techniques have been demonstrated to have high sensitivity for detecting hemorrhage and residual iron. The conventional T2*-based imaging employed for IMH imaging is based on a 2D breath-held, ECG-triggered, segmented, multi-gradient-echo sequence. More recently, a dark-blood cardiac T2* MRI technique has emerged for imaging of global iron overload such as thalassemia. It has been interchangeably used with bright-blood T2* MRI for imaging of local iron overload such as intramyocardial hemorrhage. To date however, dark-blood T2* techniques for intramyocardial hemorrhage characterization has not been validated. In Chapters 2 and 3, we investigated the diagnostic capacity of dark-blood T2* MRI against bright-blood T2* MRI for intramyocardial hemorrhage characterization in both clinical and preclinical settings. We found that double-inversion-recovery prepared dark-blood T2* images provide lower signal-to-noise ratio and lower contrast-to-noise ratio between hemorrhage and remote myocardium, consequently underestimating the hemorrhage extent. Dark-blood T2* MRI also demonstrated weaker sensitivity, specificity, accuracy, and inter-observer variability compared to bright-blood T2*-weighted MRI. Our studies also showed that the loss in SNR and CNR in dark-blood T2* imaging emerges from the signal loss following double-inversion-recovery preparation and insufficient recovery time between double-inversion-recovery preparation and readout. Hence, we conclude that dark-blood T2* MRI does not have the same diagnostic capacity for assessment of intramyocardial hemorrhage and bright-blood T2* MRI should be the preferred choice for clinical use. Studies have shown that fat infiltration is a common phenomenon in chronic myocardial infarction. However, signal from fat protons can confound the T2* assessment of intramyocardial hemorrhage. To address this issue, in Chapter 4, we studied the influence of fat infiltration on iron quantification in T2* mapping using a widely accepted water-fat separation algorithm. Specifically, we evaluated the temporal dependence of fat infiltration in hemorrhagic myocardial infarctions. We found that fat infiltration was observed in early and late chronic phases of myocardial infarctions, which if not corrected for, can underestimate the extent of iron content within the infarct zone. Notably, we also found that the amount of fat infiltration in chronic phase of MI was closely correlated with the amount of iron. Another major confounder in conventional 2D breath-held ECG-gated T2* imaging is motion artifacts. In clinical settings, patients with acute myocardial infarctions often find it difficult to hold their breath during cardiac MRI exams. Some patients may even suffer from arrhythmia (irregular heartbeat). Both situations can lead to unsuccessful gating during data acquisition leading to motion artifacts on T2* images especially with long echo times. To address this issue, in Chapter 5, we developed a motion-resolved fully ungated free-breathing 3D cardiac T2* imaging technique using a low-rank tensor framework to accommodate clinical needs and to mitigate motion artifacts due to unsuccessful breath-holds or ECG gating. We tested our 3D LRT technique in healthy volunteers and animal models for image quality, SNR and T2*. We found that the proposed 3D LRT technique can provide superior image quality compared to conventional T2* techniques at the same level of signal-to-noise ratio. T2* measured from proposed 3D LRT data showed excellent agreement with T2* from conventional 2D approach. We also found that a key benefit of 3D acquisition is that it permits the reconstruction of high-resolution T2* images using the proposed 3D LRT T2* approach. High-resolution T2* images from proposed 3D LRT approach showed superior image quality and diagnostic capacity for assessment of intramyocardial hemorrhage. In Chapter 6, the proposed 3D LRT T2* imaging approach was validated on an animal model for feasibility and capability for characterization of intramyocardial hemorrhage. We found that our 3D LRT approach had excellent image quality and diagnostic accuracy in the assessment of intramyocardial hemorrhage compared to the 2D breath-held and gated acquisitions. Broadly, this dissertation identified and corrected a number of critical confounders affecting the accuracy of T2* MRI in assessment of intramyocardial hemorrhage. By identifying and solving these confounders in T2* imaging, we aim to improve the diagnostic capability of MRI for prognosis and therapeutic care of patients with hemorrhagic myocardial infarctions. In future work, feasibility of the newly developed fully ungated free-breathing 3D LRT T2* imaging technique will be investigated on patients for imaging of intramyocardial hemorrhage. And the potential of high-resolution T2* imaging which greatly improved intravoxel dephasing due to off-resonance will be explored.

Download or read book Cardiac Magnetic Resonance Imaging Guided Therapies for Chronic Hemorrhagic Myocardial Infarction written by Eric Johnson and published by . This book was released on 2021 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation aims to evaluate therapies that have the potential to improve the recovery of the left ventricle (LV) following myocardial infarction (MI) burdened with intramyocardial hemorrhage (IMH). Prior studies have shown that hemorrhagic MI results in the deposition of chronic iron in the myocardium, which induces cytotoxic effects as well as impacts the normal function of the microvasculature. In order to characterize the content of intramyocardial iron, T2* magnetic resonance imaging (MRI) was used as the gold standard in non-invasive detection of cardiac iron, and therefore acts as a diagnostic guidance tool informing the efficacy of the therapies. The dissertation may be broken down into three phases, all performed with MRI guidance to elucidate: 1) mechanistic understanding of the microvascular environment in chronic MI subjects; 2) effects of iron chelation therapy via Deferiprone (DFP) administration; and 3) effects of therapeutic hypothermia (TH) induced post reperfusion. The first phase investigated the long-term changes in myocardial perfusion assessed via MRI, in patients with reperfused myocardial infarction and an animal model of ischemia reperfusion (I/R) injury. From animal studies, histology, immunohistochemistry (IHC), and western blotting analysis were performed to elucidate the mechanistic underpinnings of MRI observations. The outcomes of this study led to the discovery that hemorrhagic MI results in reduced myocardial perfusion within hemorrhagic, but not non-hemorrhagic, MI territories. Further, the protein expression investigations enabled the proposal of a mechanistic pathway to examine the role chronic iron deposition plays in the perfusion defects observed in hemorrhagic MI. The subsequent study in a canine model of hemorrhagic MI to remove iron from within chronic infarction regions using the small-molecule iron chelator deferiprone (DFP), is the first to show the potential to abrogate resting perfusion defects observed in the hemorrhagic MI setting. Furthermore, the study showed that the recovery of rest perfusion did not persist following termination of the DFP therapy, indicating the potential need for continuous, or extended, iron chelation in this population to maintain persistent benefits. Lastly, the study showed the potential beneficial impact of DFP therapy on LV remodeling by resulting in reduced end-diastolic mass, suggesting a possible role of iron in LV hypertrophy and diastolic dysfunction. Finally, a study of post-reperfusion localized therapeutic hypothermia was conducted in a pig model to evaluate the potential impact of hypothermia therapy on IMH and chronic iron deposition. This is the first study to show the capability of therapeutic hypothermia to reduce chronic iron deposition in hemorrhagic MI. The results of this study showed that post-reperfusion hypothermia did not impact acute infarct size and did not affect hemorrhage in the acute phase (day 3 post-MI). However, by 1 month hypothermia-treated animals showed significantly reduced T2*-derived iron deposition volume, which held when normalized by infarct size. By 2 months post-MI, absolute T2* values were also indicative of decreased myocardial iron content, with significantly increased T2* values (lower iron content) in hypothermia-treated animals. Furthermore, LV ejection fraction (LVEF) was significantly elevated at 2 months in the hypothermia group, suggesting a positive effect of therapeutic hypothermia on chronic LV function. In summary, this dissertation used animal models of hemorrhagic MI to investigate two promising therapeutic methods for alleviating the adverse remodeling in hemorrhagic MI subjects, showing promising results that will aid the future development of adjunctive clinical therapies for advancing treatment in MI and ischemia reperfusion injury.

Download or read book Non contrast Enhanced Cardiovascular Magnetic Resonance Imaging for Characterizing Chronic Myocardial Infarctions i e Infractions written by Avinash Kali and published by . This book was released on 2015 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: Myocardial infarction (MI) is the leading cause of morbidity and death globally. Non-invasive characterization of chronic MIs is of significant clinical importance due to its association with adverse cardiac outcomes such as cardiac arrhythmias, heart failure, and sudden cardiac death. Late Gadolinium Enhancement (LGE) MRI has evolved into a robust non-invasive imaging technique for characterizing chronic MIs and identifying new pathophysiological substrates of adverse cardiac outcomes within chronic MIs. However, the requisite Gadolinium administration in LGE MRI is contra-indicated in nearly 25% of the MI patients due to co-morbidity of chronic kidney disease. In this light, there has been a growing interest to develop non-contrast enhanced MRI techniques for robust characterization of chronic MIs. This dissertation focuses on the development of novel non-Gadolinium based MRI techniques for robust characterization of chronic MIs and pathological substrates of adverse cardiac outcomes. Using extensive histopathology in an animal model and validation studies in chronic MI patients, native T1 mapping at 3T was shown to characterize chronic MIs with high diagnostic accuracy. The second part of the dissertation focuses on detecting post-reperfusion intramyocardial hemorrhage using non-contrast enhanced MRI techniques, and its role as a potential pathological substrate of adverse cardiac outcomes in chronic MIs. Using histopathology and mass spectrometry analysis, T2* MRI was shown to be a highly sensitive technique for detecting hemorrhage and its degradation byproducts. Hemorrhage was found to persist within chronic MIs for several months post-MI in the form of localized iron deposits, which in turn was found to be associated with prolonged inflammatory burden and adverse left-ventricular remodeling. Using high-resolution electroanatomical maps co-registered with T2*-weighted images, localized iron deposition within chronic MIs was found to be a potential arrhythmogenic substrate. The prognostic value of cardiac T2* MRI for risk-stratifying patients susceptible to malignant ventricular arrhythmias was evaluated.

Download or read book Clinical Emergency Radiology written by J. Christian Fox and published by Cambridge University Press. This book was released on 2017-03-16 with total page 653 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a highly visual guide to the radiographic and advanced imaging modalities - such as computed tomography and ultrasonography - that are frequently used by physicians during the treatment of emergency patients. Covering practices ranging from ultrasound at the point of care to the interpretation of CT scan results, this book contains over 2,200 images, each with detailed captions and line-art that highlight key findings. Within each section, particular attention is devoted to practical tricks of the trade and tips for avoiding common pitfalls. Overall, this book is a useful source for experienced clinicians, residents, mid-level providers, or medical students who want to maximize the diagnostic accuracy of each modality without losing valuable time.

Download or read book Quantitative Magnetic Resonance Imaging written by Nicole Seiberlich and published by Academic Press. This book was released on 2020-11-18 with total page 1094 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantitative Magnetic Resonance Imaging is a 'go-to' reference for methods and applications of quantitative magnetic resonance imaging, with specific sections on Relaxometry, Perfusion, and Diffusion. Each section will start with an explanation of the basic techniques for mapping the tissue property in question, including a description of the challenges that arise when using these basic approaches. For properties which can be measured in multiple ways, each of these basic methods will be described in separate chapters. Following the basics, a chapter in each section presents more advanced and recently proposed techniques for quantitative tissue property mapping, with a concluding chapter on clinical applications. The reader will learn: - The basic physics behind tissue property mapping - How to implement basic pulse sequences for the quantitative measurement of tissue properties - The strengths and limitations to the basic and more rapid methods for mapping the magnetic relaxation properties T1, T2, and T2* - The pros and cons for different approaches to mapping perfusion - The methods of Diffusion-weighted imaging and how this approach can be used to generate diffusion tensor - maps and more complex representations of diffusion - How flow, magneto-electric tissue property, fat fraction, exchange, elastography, and temperature mapping are performed - How fast imaging approaches including parallel imaging, compressed sensing, and Magnetic Resonance - Fingerprinting can be used to accelerate or improve tissue property mapping schemes - How tissue property mapping is used clinically in different organs - Structured to cater for MRI researchers and graduate students with a wide variety of backgrounds - Explains basic methods for quantitatively measuring tissue properties with MRI - including T1, T2, perfusion, diffusion, fat and iron fraction, elastography, flow, susceptibility - enabling the implementation of pulse sequences to perform measurements - Shows the limitations of the techniques and explains the challenges to the clinical adoption of these traditional methods, presenting the latest research in rapid quantitative imaging which has the possibility to tackle these challenges - Each section contains a chapter explaining the basics of novel ideas for quantitative mapping, such as compressed sensing and Magnetic Resonance Fingerprinting-based approaches

Download or read book Magnetic Resonance Elastography written by Sudhakar K. Venkatesh and published by Springer. This book was released on 2014-10-01 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first book to cover the groundbreaking development and clinical applications of Magnetic Resonance Elastography, this book is essential for all practitioners interested in this revolutionary diagnostic modality. The book is divided into three sections. The first covers the history of MRE. The second covers technique and clinical applications of MRE in the liver with respect to fibrosis, liver masses, and other diseases. Case descriptions are presented to give the reader a hands-on approach. The final section presents the techniques, sequence and preliminary results of applications in other areas of the body including muscle, brain, lung, heart, and breast.

Download or read book The Stroke Book written by Michel T. Torbey and published by Cambridge University Press. This book was released on 2013-07-18 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: An essential companion for busy professionals seeking to navigate stroke-related clinical situations successfully and make quick informed treatment decisions.

Download or read book Core Topics in Cardiac Anesthesia written by Jonathan H. Mackay and published by Cambridge University Press. This book was released on 2012-03-15 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the publication of the first edition of Core Topics in Cardiac Anaesthesia, the clinical landscape has undergone significant change. Recent developments include the increased use of electrophysiology, the resurgence of primary percutaneous intervention in acute coronary syndromes, the use of percutaneous devices in patients previously considered inoperable, and the withdrawal of aprotinin. Against this landscape, this invaluable resource has been fully updated. New chapters are dedicated to right heart valves, pulmonary vascular disease, cardiac tumours and cardiac trauma. All other chapters have been updated according to the latest international guidelines. Written and edited by an international author team with a wealth of expertise in all aspects of the perioperative care of cardiac patients, topics are presented in an easy to digest and a readily accessible manner. Core Topics in Cardiac Anaesthesia, Second Edition is essential reading for residents and fellows in anaesthesia and cardiac surgery and clinical perfusionists.

Download or read book Common Pitfalls in Cerebrovascular Disease written by José Biller and published by Cambridge University Press. This book was released on 2015-07-09 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clinical case studies have long been recognized as a useful adjunct to problem-based learning and continuing professional development. They emphasize the need for clinical reasoning, integrative thinking, problem-solving, communication, teamwork and self-directed learning – all desirable generic skills for health care professionals. This book is a teaching tool that bridges the gap between textbook information and everyday experience of clinicians 'in the trenches'. Leading practitioners bring a practical approach to these complex conditions, highlighting specific areas of diagnostic uncertainty in evaluation and treatment. Each case is taken from real-world clinical practice and reviews the diagnostic and treatment process in a systematic manner, identifying common challenges and potential pitfalls. This concise and useful guide in the Common Pitfalls series provides a step-by-step guide for everyday clinical practice, invaluable to anyone dealing with cerebrovascular disease on a front-line basis. The intended readership is trainees and non-specialist practitioners in neurology, stroke medicine, and neurosurgery.

Download or read book Spectral Photon Counting Computed Tomography written by Katsuyuki Taguchi and published by CRC Press. This book was released on 2020-07-14 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spectral, Photon Counting Computed Tomography is a comprehensive cover of the latest developments in the most prevalent imaging modality (x-ray computed tomography (CT)) in its latest incarnation: Spectral, Dual-Energy, and Photon Counting CT. Disadvantages of the conventional single-energy technique used by CT technology are that different materials cannot be distinguished and that the noise is larger. To address these problems, a novel spectral CT concept has been proposed. Spectral Dual-Energy CT (DE-CT) acquires two sets of spectral data, and Spectral Photon Counting CT (PC-CT) detects energy of x-ray photons to reveal additional material information of objects by using novel energy-sensitive, photon-counting detectors. The K-edge imaging may be a gateway for functional or molecular CT. The book covers detectors and electronics, image reconstruction methods, image quality assessments, a simulation tool, nanoparticle contrast agents, and clinical applications for spectral CT.

Download or read book Acute Heart Failure written by Alexandre Mebazaa and published by Springer Science & Business Media. This book was released on 2009-12-24 with total page 922 pages. Available in PDF, EPUB and Kindle. Book excerpt: For many years, there has been a great deal of work done on chronic congestive heart failure while acute heart failure has been considered a difficult to handle and hopeless syndrome. However, in recent years acute heart failure has become a growing area of study and this is the first book to cover extensively the diagnosis and management of this complex condition. The book reflects the considerable amounts of new data reported and many new concepts which have been proposed in the last 3-4 years looking at the epidemiology, diagnostic and treatment of acute heart failure.

Download or read book The Right Ventricle written by Marvin A. Konstam and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is quite natural that literature related to car heart disease, cardiomyopathy, pulmonary and diac structure, function, pathology, and patho pulmonary vascular disease, trauma, acquired valvular disease, congenital disease, and surgi physiology has emphasized the left heart and systemic circulation. The relative lack of im cal considerations. The pathologic and clinical relevance of myocardial infarction of the right portance of the right ventricle was supported by studies performed in the 1940s and 1950s ventricle has only been documented over the which suggested that the right ventricular free last 15 years. The chapter on right ventricular wall could be effectively destroyed in an animal infarction integrates clinical, functional, patho model without detectable untoward hemody physiologic, and pathologic observations to pro namic consequences. The relative inadequacy vide the reader with a thorough review, equally of noninvasive tools to study right ventricular relevant to the clinician and investigator. The contribution on dilated cardiomyopathy pro structure and function obviated detailed and systematic investigation. However, over the vides novel insight into the impact of right ventricular performance on the functional in past 15 years there has been a resurgence of interest in the right ventricle by a variety of capacity accompanying left heart failure. A book dealing with the right ventricle would investigators. The skeptic would argue that this renewed interest resulted from an exhaustion be incomplete without at least cursory reference we have of clinically-related observations that could be to the pulmonary circulation.

Download or read book Essentials of Restenosis written by Henricus J. Duckers and published by Springer Science & Business Media. This book was released on 2007-11-13 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: Leading interventional cardiologists, including Patrick Serruys, provide the gold-standard reference on the treatment of restenosis for interventional cardiologists. Dr. Serruys, who pioneered the use of drug-eluting stents, and other pioneers in the field, cover everything from non-invasive imaging, to eluting stents, to brachytherapy through to the latest molecular biology-based treatments including antisense, stem cells and gene therapy.

Download or read book Management of Acute Pulmonary Embolism written by Stavros V. Konstantinides and published by Springer Science & Business Media. This book was released on 2007-12-31 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: This practical volume highlights traditional, novel, and evolving aspects of the diagnosis and treatment of pulmonary embolism (PE). The contributors comprise an international team of experts. Important aspects of diagnosis, risk stratification, and differential treatment of patients with PE are presented in a concise, yet comprehensive manner. Emphasis is placed on specific issues related to PE, including pregnancy, cancer, thrombophilia, and air travel.

Download or read book AACN Protocols for Practice Noninvasive Monitoring Second Edition written by Burns and published by Jones & Bartlett Publishers. This book was released on 2005-09-22 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: AACN Protocols for Practice: Noninvasive Monitoring delineates the evidence for using devices for noninvasive patient monitoring of blood pressure, heart rhythms, pulse oximetry, end-tidal carbon dioxide, and respiratory waveforms. These protocols guide clinicians in the appropriate selection of patients for use of the device, application of the device, initial and ongoing monitoring, device removal, and selected aspects of quality control. AACN Protocols for Practice are authoritative evidence-based practice resources for use by clinicians, educators, and researchers. Each series of protocols makes recommendations for the application, practice, and monitoring associated with a device, procedure, or practice.

Download or read book Acute Ischemic Stroke written by R. Gilberto González and published by Springer Science & Business Media. This book was released on 2010-10-05 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: This updated second edition of Acute Ischemic Stroke: Imaging and Intervention provides a comprehensive account of the state of the art in the diagnosis and treatment of acute ischemic stroke. The basic format of the first edition has been retained, with sections on fundamentals such as pathophysiology and causes, imaging techniques and interventions. However, each chapter has been revised to reflect the important recent progress in advanced neuroimaging and the use of interventional tools. In addition, a new chapter is included on the classification instruments for ischemic stroke and their use in predicting outcomes and therapeutic triage. All of the authors are internationally recognized experts and members of the interdisciplinary stroke team at the Massachusetts General Hospital and Harvard Medical School. The text is supported by numerous informative illustrations, and ease of reference is ensured through the inclusion of suitable tables. This book will serve as a unique source of up-to-date information for neurologists, emergency physicians, radiologists and other health care providers who care for the patient with acute ischemic stroke.

Download or read book Stroke Syndromes 3ed written by Louis R. Caplan and published by Cambridge University Press. This book was released on 2012-07-12 with total page 633 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive survey of dysfunction due to stroke, this revised edition remains the definitive guide to stroke patterns and syndromes.