Download or read book Parallel Radiofrequency Transmission for 3 Tesla and 7 Tesla Magnetic Resonance Imaging written by Filiz Yetişir and published by . This book was released on 2017 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic resonance imaging (MRI) is a noninvasive imaging technique with high soft tissue contrast. MR scanners are characterized by their main magnetic field strength. Commercially available clinical MR scanners commonly have main field strengths of 1.5 and 3 Tesla. Researchers increasingly explore clinical benefits of higher field strength scanners as they provide higher signal to noise ratio and higher resolution images. On the other hand, higher field strength imaging comes with increased image shading leading to non-uniform image contrast. Moreover, the tissue heating rate due to radiofrequency (RF) energy deposition (also called specific absorption rate or SAR) increases, limiting the imaging speed. Parallel RF transmission (pTx) was proposed to address both of these challenges by optimization of RF pulses transmitted from multiple independent channels simultaneously. However, both the RF pulse design and RF safety management become more complicated with pTx. In this work, a framework to apply pTx to 3T fetal and 7T brain imaging is developed to address the image shading and high SAR issues. Fetal imaging where a large pregnant torso is imaged rapidly to avoid fetal motion artifacts, suffers from similar levels of image shading and imaging limitations by SAR to 7T brain MRI. Hence the same techniques benefit both application domains. First, a SAR constrained pTx RF pulse design technique is developed for slice selective high flip angle imaging which is clinically the most common imaging technique. Next, the performance of the developed technique in reducing SAR and the image contrast non-uniformity is demonstrated through simulations and in phantom experiments for 7T brain imaging. Then, a comprehensive RF safety workflow for an 8 channel pTx system at 7T is developed. Finally, the potential of pTx for fetal imaging at 3T is demonstrated with simulation studies and a protected fetus mode of pTx was created using additional constraints in the RF pulse design. By addressing the two main RF transmission challenges associated with high and ultrahigh field MRI, this work aims to help bring the benefits of 7T brain imaging into routine clinical use and significantly improve the clinical experience for 3T fetal imaging.
Download or read book Applications of Parallel Radiofrequency Transmission to Ultra high field Magnetic Resonance Imaging written by Yan Tong and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Parallel Transmission for Magnetic Resonance Imaging of the Human Brain at Ultra High Field written by Martijn Anton Hendrik Cloos and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The focus of this thesis lies on the development, and implementation, of parallel transmission (pTx) techniques in magnetic resonance imaging for flip-angle homogenization throughout the human brain at ultra-high field. In order to allow in-vivo demonstrations, a conservative yet viable safety concept is introduced to control the absorbed radiofrequency (RF) power . Subsequently, novel methods for local SAR control and non-selective RF pulse-design are investigated. The impact of these short and energy-efficient waveforms, referred to as kT-points, is first demonstrated in the context of the small-tip-angle domain. Targeting a larger scope of applications, the kT-points design is then generalized to encompass large flip angle excitations and inversions. This concept is applied to one of the most commonly used T1-weighted sequences in neuroimaging. Results thus obtained at 7 Tesla are compared to images acquired with a clinical setup at 3 Tesla, validating the principles of the kT-points method and demonstrating that pTx-enabled ultra-high field systems can also be competitive in the context of T1-weighted imaging. Finally, simplifications in the global design of the pTx-implementation are studied in order to obtain a more cost-effective solution.
Download or read book Contrast Enhanced Clinical Magnetic Resonance Imaging written by Val M. Runge and published by University Press of Kentucky. This book was released on 1997 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Body MR Imaging at 3 Tesla written by Ihab R. Kamel and published by Cambridge University Press. This book was released on 2011-08-04 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: Guides radiologists in optimizing protocols for 3T MR systems, reducing artifacts and identifying the advantages of 3T in body applications.
Download or read book Ultra High Field Magnetic Resonance Imaging written by Pierre-Marie Robitaille and published by Springer Science & Business Media. This book was released on 2007-12-31 with total page 487 pages. Available in PDF, EPUB and Kindle. Book excerpt: The foundation for understanding the function and dynamics of biological systems is not only knowledge of their structure, but the new methodologies and applications used to determine that structure. This volume in Biological Magnetic Resonance emphasizes the methods that involve Ultra High Field Magnetic Resonance Imaging. It will interest researchers working in the field of imaging.
Download or read book Towards High Field MRI Systems written by Nadine Kolment and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "High-field magnetic resonance imaging (MRI) is a very promising concept as it benefits from a significant improvement in the signal-to-noise ratio (SNR), a measure that directly affects image resolution. However, as the resonant wavelength approaches the dimensions of the object being imaged, the wave propagation effects of the radio frequency (RF) field significantly deteriorate the uniformity of the excitation pattern, thus leading to contrast aberrations and distortions in the resulting image. Recent proof-of-concept studies have shown the merits of parallel transmission techniques in accurately controlling the RF magnetic field whereas novel coil arrangements, such as the TEM resonator, have provided the necessary platform for conducting truly parallel excitations experiments. The purpose of this thesis is to provide a comprehensive study on the design of the TEM resonator by comparing two modelling techniques. The first technique uses multi-conductor transmission line theory to model the coil; the second technique uses the brute-force computational algorithm called finite-difference time-domain (FDTD). The two techniques are compared in terms of the S11 trends observed while varying TEM resonator design parameters such as the capacitor values and the line element geometry. A difference of 15% in the coil response was observed for an MRI system of 3-Tesla field strength. This modelling error increases with resonant frequency and reaches the 40% mark for a high-field MRI system of 7-Tesla field strength. Despite the diverging results for increasing frequency, this study shows that the variation of design parameters in each modelling technique exhibit comparable trends." --
Download or read book 7T MRI An Issue of Magnetic Resonance Imaging Clinics of North America written by Meng Law and published by Elsevier Health Sciences. This book was released on 2020-11-30 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: This issue of MRI Clinics of North America focuses on 7T MRI and is edited by Dr. Meng Law. Articles will include: 3T vs 7T MRI: Is It Really Worth It?; High Resolution Structural MRI & Quantitative Susceptibility Mapping; High Resolution Neurovascular Imaging at 7T: Arterial Spin Labeling Perfusion, 4-dimensional MR Angiography and Black blood MRI; 7T and Beyond Functional MRI; Sodium and Other UHF MRI; MR-EYE: Ultra High Field MRI of the Human Eye and Orbit at 7T; 7T MRI of Perivascular Spaces; 7T MRI in “Non Lesional" Epilepsy/ Perivascular Spaces; 7T Multiple Sclerosis; 7T Brain Tumors and Radiation Therapy; 7T Musculoskeletal MRI; Body Applications for 7T; MRI Safety at 7T/Implants; 7T Simultaneous MRI PET with PET Insert; GluCest 7T MRI; and more!
Download or read book Cardiovascular Magnetic Resonance written by Warren J. Manning and published by Elsevier Health Sciences. This book was released on 2018-04-26 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides state-of-the-art coverage of CMR technologies and guidelines, including basic principles, imaging techniques, ischemic heart disease, right ventricular and congenital heart disease, vascular and pericardium conditions, and functional cardiovascular disease. Includes new chapters on non-cardiac pathology, pacemaker safety, economics of CMR, and guidelines as well as new coverage of myocarditis and its diagnosis and assessment of prognosis by cardiovascular magnetic resonance, and the use of PET/CMR imaging of the heart, especially in sarcoidosis. Features more than 1,100 high-quality images representing today’s CMR imaging. Covers T1, T2 and ECV mapping, as well as T2* imaging in iron overload, which has been shown to save lives in patients with thalassaemia major Discusses the cost-effectiveness of CMR.
Download or read book Brain and Human Body Modeling written by Sergey Makarov and published by Springer Nature. This book was released on 2019-08-27 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book describes modern applications of computational human modeling with specific emphasis in the areas of neurology and neuroelectromagnetics, depression and cancer treatments, radio-frequency studies and wireless communications. Special consideration is also given to the use of human modeling to the computational assessment of relevant regulatory and safety requirements. Readers working on applications that may expose human subjects to electromagnetic radiation will benefit from this book’s coverage of the latest developments in computational modelling and human phantom development to assess a given technology’s safety and efficacy in a timely manner. Describes construction and application of computational human models including anatomically detailed and subject specific models; Explains new practices in computational human modeling for neuroelectromagnetics, electromagnetic safety, and exposure evaluations; Includes a survey of modern applications for which computational human models are critical; Describes cellular-level interactions between the human body and electromagnetic fields.
Download or read book MRI written by Mark A. Brown and published by John Wiley & Sons. This book was released on 2011-01-14 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fourth Edition Brings This Popular Guide Thoroughly Up To Date With The Latest MRI Findings, Techniques, And Applications For its Fourth Edition, the acclaimed MRI: Basic Principles and Applications has been rigorously revised, enabling readers to quickly master the principles and take advantage of all the latest MRI applications. Among the new materials are fresh and updated discussions on 3D imaging, real-time imaging, cardiac imaging, and parallel acquisition techniques. In addition, readers will find dozens of brand-new images to illustrate key concepts. Moreover, clinical protocols have been thoroughly updated and revised to reflect current methodologies. Throughout the book, readers will find easy-to-follow coverage of all the latest findings, technologies, and techniques, including: Nephrotoxic effects of gadolinium-based contrast media New scan techniques, including radial scanning Parallel acquisition and cardiovascular imaging techniques New applications, including spin tagging and diffusion tensor imaging 3 Tesla and 7 Tesla scanning Hardware innovations, including large-scale array coils New motion compensation techniques With its clear explanations and ample illustrations, this Fourth Edition maintains all the hallmarks of the previous edition that have made this book a fixture in MRI labs around the world. Students and practitioners—from physicians to radiologists to technicians—will gain a full, accurate understanding of the underlying physics and the clinical applications of MRI, all with a minimum of mathematical formulas and technical details. From Reviews of the Third Edition ". . . successful in transferring key ideas in an undaunting and progressive manner . . . thoroughly deserves a place on the bookshelf." —NMR in Biomedicine, Vol 17(4), June 2004 ". . . it will reward the reader with an understanding of the principles underpinning nuclear magnetic resonance." —Yale Journal of Biology and Medicine, May 2003
Download or read book Magnetic Resonance Imaging in Deep Brain Stimulation written by Alexandre Boutet and published by Springer Nature. This book was released on 2022-11-28 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the roles magnetic resonance imaging (MRI) can play in deep brain stimulation (DBS). DBS therapeutically modulates aberrant neural circuits implicated in a broad range of neurological disorders. Following surgical insertion, an electrode placed into the desired brain target generates constant electricity, analogous to a cardiac pacemaker. Most commonly employed in movement disorders such as Parkinson’s disease, dystonia, and tremor, DBS is also being investigated for use in psychiatric and cognitive disorders, including depression and Alzheimer’s disease. It is estimated that more than 230,000 patients have undergone DBS surgery worldwide. Imaging techniques, specifically MRI, have played key roles in the preoperative and postoperative aspects of DBS. This book focuses on the established as well as the innovative roles of MRI in DBS. MRI and DBS are first introduced from an historical perspective and a review of the clinical aspects of DBS is performed. Then, the preoperative and postoperative applications of MRI in DBS are covered. The crucial aspect of MRI safety in these patients is also discussed. Finally, possible upcoming MRI applications for patients with DBS are discussed in a future directions chapter. Chapters are written by experts from the University of Toronto, a world leader in the field of DBS, alongside international co-authors to ensure a thorough review of the topics. This is an ideal guide for both clinicians (neurosurgeons, neurologists, psychiatrists, and neuroradiologists) and researchers as well as trainees interested in neuroimaging for DBS.
Download or read book Cardiac CT PET and MR written by Vasken Dilsizian and published by John Wiley & Sons. This book was released on 2019-07-04 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt: A complete guide to non-invasive imaging techniques in cardiology Todays imaging technologies offer cardiologists more ways than ever to diagnose conditions of the heart without the need of endoscopies and other invasive procedures. Now in its third edition,Cardiac CT, PET and MRI continues to provide an in-depth explanation of these tools and their correct applications, while also exploring cardiac imagings most recent and groundbreaking developments. This wide-ranging guide places CT, PET and MRI in a practical context, illustrating clearly their respective functions as they apply to specific cardiological disorders and clinical situations. With the addition of seven new chapters, it also offers an expanded insight into PET an increasingly popular and affordable diagnostic utility, hitherto underexplored in texts devoted to imaging. Cardiac CT, PET and MRI includes: Clinically focused examinations of CT, PET and MRI the three most popular non-invasive imaging modalities Illustrative full-color photos and images Access to a companion website featuring additional content Cardiologists, radiologists, nuclear medicine physicians, physicists, and imaging technologists alike will find the third edition of Cardiac CT, PET and MRI an informative and accessible resource with a direct use in their day-to-day practice.
Download or read book Simultaneous EEG and fMRI written by Markus Ullsperger and published by Oxford University Press. This book was released on 2010-05-28 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the major challenges in science is to study and understand the human brain. Numerous methods examining different aspects of brain functions have been developed and employed. To study systemic interactions brain networks in vivo, non-invasive methods such as electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) have been used with great success. However, each of these methods can map only certain, quite selective aspects of brain function while missing others; and the inferences on neuronal processes and information flow are often rather indirect. To overcome these shortcomings of single methods, researchers have attempted to combine methods in order to make optimal use of their advantages while compensating their disadvantages. Hence, it is not surprising that soon after the introduction of fMRI as a neuroimaging method the possibilities of combinations with EEG have been explored. This book is intended to aid researchers who plan to set up a simultaneous EEG-fMRI laboratory and those who are interested in integrating electrophysiological and hemodynamic data. As will be obvious from the different chapters, this is a dynamically developing field in which several approaches are being tested, validated and compared. Currently, there is no one best solution for all problems available, but many promising techniques are emerging. This book shall give a comprehensive overview of these techniques. In addition, it points to open questions and directions for future research.
Download or read book Electromagnetics in Magnetic Resonance Imaging written by Christopher M. Collins and published by Morgan & Claypool Publishers. This book was released on 2016-03-01 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past few decades, Magnetic Resonance Imaging (MRI) has become an indispensable tool in modern medicine, with MRI systems now available at every major hospital in the developed world. But for all its utility and prevalence, it is much less commonly understood and less readily explained than other common medical imaging techniques. Unlike optical, ultrasonic, X-ray (including CT), and nuclear medicine-based imaging, MRI does not rely primarily on simple transmission and/or reflection of energy, and the highest achievable resolution in MRI is orders of magnitude smaller that the smallest wavelength involved. In this book, MRI will be explained with emphasis on the magnetic fields required, their generation, their concomitant electric fields, the various interactions of all these fields with the subject being imaged, and the implications of these interactions to image quality and patient safety. Classical electromagnetics will be used to describe aspects from the fundamental phenomenon of nuclear precession through signal detection and MRI safety. Simple explanations and Illustrations combined with pertinent equations are designed to help the reader rapidly gain a fundamental understanding and an appreciation of this technology as it is used today, as well as ongoing advances that will increase its value in the future. Numerous references are included to facilitate further study with an emphasis on areas most directly related to electromagnetics.
Download or read book Muscle Cell and Tissue written by Kunihiro Sakuma and published by BoD – Books on Demand. This book was released on 2018-10-10 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to complete tissue regeneration, various cells (neuronal, skeletal and smooth) interact coordinately with each other. This book, Muscle Cell and Tissue - Current Status of Research Field, deals with current progress and perspectives in a variety of topics on the skeletal and smooth muscle, stem cells, regeneration, disease or therapeutics. Novel applications for cell and tissue engineering including cell therapy, tissue models and disease pathology modeling are introduced. This book also deals with the differentiation/de-differentiation process of vascular smooth muscle cells in health and disease. Furthermore, natural products to reverse metabolic syndromes are descriptively reviewed. These chapters can be interesting for graduate students, teachers, physicians, executives and researchers in the field of molecular biology and regenerative medicine.
Download or read book The Physics and Mathematics of MRI written by Richard Ansorge and published by Morgan & Claypool Publishers. This book was released on 2016-11-01 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic Resonance Imaging is a very important clinical imaging tool. It combines different fields of physics and engineering in a uniquely complex way. MRI is also surprisingly versatile, 'pulse sequences' can be designed to yield many different types of contrast. This versatility is unique to MRI. This short book gives both an in depth account of the methods used for the operation and construction of modern MRI systems and also the principles of sequence design and many examples of applications. An important additional feature of this book is the detailed discussion of the mathematical principles used in building optimal MRI systems and for sequence design. The mathematical discussion is very suitable for undergraduates attending medical physics courses. It is also more complete than usually found in alternative books for physical scientists or more clinically orientated works.
