Download or read book Universal Parallel Transmission Pulse Design for the Human Brain and Spinal Cord MRI at 9 4T written by Ole Geldschläger and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Non selective Refocusing Pulse Design in Parallel Transmission for Magnetic Resonance Imaging of the Human Brain at Ultra High Field written by Aurélien Massire and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Magnetic Resonance Imaging (MRI), the increase of the static magnetic field strength is used to provide in theory a higher signal-to-noise ratio, thereby improving the overall image quality. The purpose of ultra-high-field MRI is to achieve a spatial image resolution sufficiently high to be able to distinguish structures so fine that they are currently impossible to view in a non-invasive manner. However, at such static magnetic fields strengths, the wavelength of the electromagnetic waves sent to flip the water proton spins is of the same order of magnitude than the scanned object. Interference wave phenomena are then observed, which are caused by the radiofrequency (RF) field inhomogeneity within the object. These generate signal and/or contrast artifacts in MR images, making their exploitation difficult, if not impossible, in certain areas of the body. It is therefore crucial to provide solutions to mitigate the non-uniformity of the spins excitation. Failing this, these imaging systems with very high fields will not reach their full potential.For relevant high field clinical diagnosis, it is therefore necessary to create RF pulses homogenizing the excitation of all spins (here of the human brain), and optimized for each individual to be imaged. For this, an 8-channel parallel transmission system (pTX) was installed in our 7 Tesla scanner. While most clinical MRI systems only use a single transmission channel, the pTX extension allows to simultaneously playing various forms of RF pulses on all channels. The resulting sum of the interference must be optimized in order to reduce the non-uniformity typically seen.The objective of this thesis is to synthesize this type of tailored RF pulses, using parallel transmission. These pulses will have as an additional constraint the compliance with the international exposure limits for radiofrequency exposure, which induces a temperature rise in the tissue. In this sense, many electromagnetic and temperature simulations were carried out as an introduction of this thesis, in order to assess the relationship between the recommended RF exposure limits and the temperature rise actually predicted in tissues.This thesis focuses specifically on the design of all RF refocusing pulses used in non-selective MRI sequences based on the spin-echo. Initially, only one RF pulse was generated for a simple application: the reversal of spin dephasing in the transverse plane, as part of a classic spin echo sequence. In a second time, sequences with very long refocusing echo train applied to in vivo imaging are considered. In all cases, the mathematical operator acting on the magnetization, and not its final state as is done conventionally, is optimized. The gain in high field imaging is clearly visible, as the necessary mathematical operations (that is to say, the rotation of the spins) are performed with a much greater fidelity than with the methods of the state of the art. For this, the generation of RF pulses is combining a k-space-based spin excitation method, the kT-points, and an optimization algorithm, called Gradient Ascent Pulse Engineering (GRAPE), using optimal control.This design is relatively fast thanks to analytical calculations rather than finite difference methods. The inclusion of a large number of parameters requires the use of GPUs (Graphics Processing Units) to achieve computation times compatible with clinical examinations. This method of designing RF pulses has been experimentally validated successfully on the NeuroSpin 7 Tesla scanner, with a cohort of healthy volunteers. An imaging protocol was developed to assess the image quality improvement using these RF pulses compared to typically used non-optimized RF pulses. All methodological developments made during this thesis have contributed to improve the performance of ultra-high-field MRI in NeuroSpin, while increasing the number of MRI sequences compatible with parallel transmission.
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 Quantitative MRI of the Spinal Cord written by Julien Cohen-Adad and published by Academic Press. This book was released on 2014-01-16 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantitative MRI of the Spinal Cord is the first book focused on quantitative MRI techniques with specific application to the human spinal cord. This work includes coverage of diffusion-weighted imaging, magnetization transfer imaging, relaxometry, functional MRI, and spectroscopy. Although these methods have been successfully used in the brain for the past 20 years, their application in the spinal cord remains problematic due to important acquisition challenges (such as small cross-sectional size, motion, and susceptibility artifacts). To date, there is no consensus on how to apply these techniques; this book reviews and synthesizes state-of-the-art methods so users can successfully apply them to the spinal cord. Quantitative MRI of the Spinal Cord introduces the theory behind each quantitative technique, reviews each theory’s applications in the human spinal cord and describes its pros and cons, and suggests a simple protocol for applying each quantitative technique to the spinal cord. Chapters authored by international experts in the field of MRI of the spinal cord Contains “cooking recipes —examples of imaging parameters for each quantitative technique—designed to aid researchers and clinicians in using them in practice Ideal for clinical settings
Download or read book Motion robust Pulse Design for Parallel Transmission Excitation at Ultra high Field MRI written by Luke Watkins and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This note is part of Quality testing.
Download or read book Fast High flip angle MRI Pulse Design for Parallel RF Transmission written by Rene Gumbrecht and published by . This book was released on 2010 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Parallel Imaging in Clinical MR Applications written by Stefan O. Schönberg and published by Springer Science & Business Media. This book was released on 2007-01-11 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the first in-depth introduction to parallel imaging techniques and, in particular, to the application of parallel imaging in clinical MRI. It will provide readers with a broader understanding of the fundamental principles of parallel imaging and of the advantages and disadvantages of specific MR protocols in clinical applications in all parts of the body at 1.5 and 3 Tesla.
Download or read book MRI from Picture to Proton written by Donald W. McRobbie and published by Cambridge University Press. This book was released on 2017-04-13 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: MR is a powerful modality. At its most advanced, it can be used not just to image anatomy and pathology, but to investigate organ function, to probe in vivo chemistry, and even to visualise the brain thinking. However, clinicians, technologists and scientists struggle with the study of the subject. The result is sometimes an obscurity of understanding, or a dilution of scientific truth, resulting in misconceptions. This is why MRI from Picture to Proton has achieved its reputation for practical clarity. MR is introduced as a tool, with coverage starting from the images, equipment and scanning protocols and traced back towards the underlying physics theory. With new content on quantitative MRI, MR safety, multi-band excitation, Dixon imaging, MR elastography and advanced pulse sequences, and with additional supportive materials available on the book's website, this new edition is completely revised and updated to reflect the best use of modern MR technology.
Download or read book Review of Radiologic Physics written by William Sensakovic and published by Lippincott Williams & Wilkins. This book was released on 2023-07-24 with total page 537 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offering a complete review for radiology residents and radiologic technologists preparing for certification, Review of Radiologic Physics, 5th Edition, by Dr. William F. Sensakovic, is a high-yield, efficient resource for today’s clinically focused exams. Now fully up to date, this edition covers x-ray production and interactions, projection and tomographic imaging, image quality, radiobiology, radiation protection, nuclear medicine, ultrasound, and magnetic resonance—all of the important physics information you need to understand the factors that improve or degrade image quality.
Download or read book Magnetic Resonance and Its Applications written by Vladimir I. Chizhik and published by Springer Science & Business Media. This book was released on 2014-04-08 with total page 785 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book is devoted to the description of the fundamentals in the area of magnetic resonance. The book covers two domains: radiospectroscopy and quantum radioelectronics. Radiospectroscopy comprises nuclear magnetic resonance , electron paramagnetic resonance, nuclear quadrupolar resonance, and some other phenomena. The radiospectroscopic methods are widely used for obtaining the information on internal (nano, micro and macro) structure of objects. Quantum radioelectronics, which was developed on the basis of radiospectroscopic methods, deals with processes in quantum amplifiers, generators and magnetometers. We do not know analogues of the book presented. The book implies a few levels of the general consideration of phenomena, that can be useful for different groups of readers (students, PhD students, scientists from other scientific branches: physics, chemistry, physical chemistry, biochemistry, biology and medicine).
Download or read book Magnetic Resonance Procedures written by Frank G. Shellock and published by CRC Press. This book was released on 2000-12-21 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic Resonance Procedures: Health Effects and Safety is the first authoritative text on MR procedures and its associated health and safety concerns written by noted radiologists, physicists, and scientists with expertise in the field. It contains both theoretical and practical information. This timely text discusses emergent issues rela
Download or read book Neurobiology of Decision Making written by Antonio R. Damasio and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neuroscience has paid only little attention to decision-making for many years. Although no field of science has cohered around this topic, a variety of researchers in different areas of neuroscience ranging from cellular physiology to neuropsychology and computational neuroscience have been engaged in working on this issue. Thus, the time seemed to be ripe to bring these researchers together and discuss the state of the art of the neurobiology of decision-making in a broad forum. This book is a collection of contributions presented at that forum in Paris in October 1994 organized by the Fondation IPSEN.
Download or read book Nuclear Medicine Resources Manual written by International Atomic Energy Agency and published by International Atomic Energy Agency. This book was released on 2021-03-22 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Medical imaging is crucial in a variety of medical settings and at all levels of health care. In public health and preventive medicine as well as in both curative and palliative care, effective decisions depend on correct diagnoses. This edition addresses the most current needs and offers guidance on clinical practice, radiation safety and patient protection, human resource development and training required for the overall practice of nuclear medicine.
Download or read book A Text Book of Medical Instruments written by S. Ananthi and published by New Age International. This book was released on 2006 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: About the Book: This book has therefore subdivided the realm of medical instruments into the same sections like a text on physiology and introduces the basic early day methods well, before dealing with the details of present day instruments currently in
Download or read book The Decisive Moment written by Jonah Lehrer and published by Canongate Books. This book was released on 2010 with total page 305 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since Plato, philosophers have described the decision-making process as either rational or emotional: we carefully deliberate or we 'blink' and go with our gut. But as scientists break open the mind's black box with the latest tools of neuroscience, they're discovering this is not how the mind works. Our best decisions are a finely tuned blend of both feeling and reason - and the precise mix depends on the situation. When buying a house, for example, it's best to let our unconscious mull over the many variables. But when we're picking stocks and shares, intuition often leads us astray. The trick is to determine when to lean on which part of the brain, and to do this, we need to think harder (and smarter) about how we think.
Download or read book Anatomy and Physiology Coloring Workbook written by Elaine Nicpon Marieb and published by Pearson. This book was released on 2017-01-03 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: For courses in 1- and 2-semester Anatomy & Physiology Simplify your Study of Anatomy & Physiology. Combining a wide range and variety of engaging coloring activities, exercises, and self-assessments into an all-in-one Study Guide, the Anatomy and Physiology Coloring Workbook helps you simplify your study of A&P. Featuring contributions from new co-author Simone Brito, the 12th edition of this best-selling guide continues to reinforce the fundamentals of anatomy and physiology through a variety of unique, interactive activities. You now benefit from new crossword puzzles in each chapter, along with dozens of strengthened and expanded exercises, illustrations, and over 100 coloring exercises. Additional self-assessments, "At The Clinic" short answer questions, and unique "Incredible Journey" visualization exercises, further reinforce basic concepts that are relevant to health care careers.
Download or read book Wavelets in Neuroscience written by Alexander E. Hramov and published by Springer Nature. This book was released on 2021-06-16 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book illustrates how modern mathematical wavelet transform techniques offer fresh insights into the complex behavior of neural systems at different levels: from the microscopic dynamics of individual cells to the macroscopic behavior of large neural networks. It also demonstrates how and where wavelet-based mathematical tools can provide an advantage over classical approaches used in neuroscience. The authors well describe single neuron and populational neural recordings. This 2nd edition discusses novel areas and significant advances resulting from experimental techniques and computational approaches developed since 2015, and includes three new topics: • Detection of fEPSPs in multielectrode LFPs recordings. • Analysis of Visual Sensory Processing in the Brain and BCI for Human Attention Control; • Analysis and Real-time Classification of Motor-related EEG Patterns; The book is a valuable resource for neurophysiologists and physicists familiar with nonlinear dynamical systems and data processing, as well as for graduate students specializing in these and related areas.
