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Friday, July 31, 2020 | History

1 edition of Magnetic Resonance Imaging with Nonlinear Gradient Fields found in the catalog.

Magnetic Resonance Imaging with Nonlinear Gradient Fields

Signal Encoding and Image Reconstruction

by Gerrit Schultz

  • 212 Want to read
  • 16 Currently reading

Published by Springer Fachmedien Wiesbaden, Imprint: Springer Spektrum in Wiesbaden .
Written in English

    Subjects:
  • Diagnostic Radiology,
  • Measurement Science and Instrumentation,
  • Electronics,
  • Physics,
  • Instrumentation Electronics and Microelectronics,
  • Medical Radiology

  • About the Edition

    Within the past few decades magnetic resonance imaging has become one of the most important imaging modalities in medicine. For a reliable diagnosis of pathologies further technological improvements are of primary importance. This text deals with a radically new approach of image encoding: The fundamental principle of gradient linearity is challenged by investigating the possibilities of acquiring anatomical images with the help of nonlinear gradient fields. Besides a thorough theoretical analysis with a focus on signal encoding and image reconstruction, initial hardware implementations are tested using phantom as well as in-vivo measurements. Several applications are presented that give an impression about the implications that this technological advancement may have for future medical diagnostics. Contentsn Image Reconstruction in MRIn Nonlinear Gradient Encoding: PatLoc Imagingn Presentation of Initial Hardware Designsn Basics of Signal Encoding and Image Reconstruction in PatLoc Imagingn Direct and Iterative Reconstruction Techniques Target Groups· Researchers and students in the fields of physics, mathematics, medicine and engineering with interest in imaging technology.· Industrial practitioners with focus on medical imaging. About the AuthorGerrit Schultz studied Physics and Mathematics at the Universities of Heidelberg and Geneva. He joined the Medical Physics Group at the University Medical Center in Freiburg in 2007, where he is currently working as a postdoctoral researcher.

    Edition Notes

    Statementby Gerrit Schultz
    ContributionsSpringerLink (Online service)
    Classifications
    LC ClassificationsT50
    The Physical Object
    Format[electronic resource] :
    PaginationXVI, 333 p. 93 illus., 27 illus. in color.
    Number of Pages333
    ID Numbers
    Open LibraryOL27072192M
    ISBN 109783658011345

    Page Figure Time domain nuclear magnetic resonance signal from volume element dxdydz in an object of magnetization density M xy (t) in the presence of a spatial encoding gradient G.. ation terms (which can be done without loss of generality when formulating the imaging equations), the steady-state solution of equation in the presence of a static polarizing field H 0 = H z. Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio waves to generate images of the organs in the body. MRI does not involve X-rays or the use of ionizing radiation, which distinguishes it from CT and PET scans.

    New Strategies for Accelerated Spatial Encoding with Quadratic Fields in Magnetic Resonance Imaging Jason Peter Stockmann Spatial encoding with nonlinear magnetic fields has recently drawn attention for its potential to achieve faster gradient field switching within safety limits, tailored resolution in regions of interest, and improved parallel imaging using encoding fields that. Ideally an imaging gradient should produce an incremental magnetic field whose intensity varies linearly with distance from magnet isocenter. In other words, if the gradient field at distance D equals S, the gradient contribution at distance 2D should equal magnetic field homogeneity, gradient linearity falls off significantly the farther one gets from isocenter.

    A new nonlinear diffusion method to improve image quality We propose a nonlinear diffusion method based on the gradient vector field construction to remove noises in image while preserving fine details. Results obtained from various images, including synthetic and magnetic resonance imaging (MRI), are used to demonstrate the performance.   Usually, the gradients vary in a linear manner over the field of view (FOV) and are defined as the rate of change of the magnetic field (B) in the direction of interest. In all, the gradients perform three functions: slice selection (z component), frequency encoding (x component), and .


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Magnetic Resonance Imaging with Nonlinear Gradient Fields by Gerrit Schultz Download PDF EPUB FB2

From the Back Cover. Within the past few decades magnetic resonance imaging has become one of the most important imaging modalities in medicine. For a reliable diagnosis of pathologies further technological improvements are of primary importance.

This text deals with a radically new approach of image encoding: The fundamental principle of gradient linearity is challenged by investigating the possibilities of acquiring anatomical images with the help of nonlinear gradient : Springer Spektrum.

Introduction. Within the past few decades magnetic resonance imaging has become one of the most important imaging modalities in medicine. For a reliable diagnosis of pathologies further technological improvements are of primary importance.

This text deals with a radically new approach of image encoding: The fundamental principle of gradient linearity is challenged by investigating the possibilities of acquiring anatomical images with the help of nonlinear gradient fields.

Magnetic Resonance Imaging with Nonlinear Gradient Fields Signal Encoding and Image Reconstruction. With the advent of parallel imaging, this approach may be questioned, making way of much a more flexible gradient hardware that uses encoding fields with an arbitrary geometry.

The theoretical basis of this new imaging modality – PatLoc Brand: Springer Spektrum. Get this from a library. Magnetic resonance imaging with nonlinear gradient fields: signal encoding and image reconstruction. [Gerrit Schultz] -- Within the past few decades magnetic resonance imaging has become one of the most important imaging modalities in medicine.

For a reliable diagnosis of pathologies further technological improvements. Get this from a library. Magnetic Resonance Imaging with Nonlinear Gradient Fields: Signal Encoding and Image Reconstruction.

[Gerrit Schultz] -- Within the past few decades MRI has become one of the most important imaging modalities in medicine. For a reliable diagnosis of pathologies further technological improvements are of primary. Magnetic resonance (MR) imaging requires three different types of magnetic fields.

First, a static and highly uniform magnetic field, known as the main field, is required to create the initial longitudinal magnetization in the object and to maintain Larmor precession of nuclear spins at.

Nonlinear spatial encoding fields for magnetic resonance imaging (MRI) hold great promise to improve on the linear gradient approaches by, for example, enabling reduced imaging times. Magnetic Resonance Imaging, Second Edition begins with an introduction to fundamental principles, with coverage of magnetization, relaxation, quantum mechanics, signal detection and acquisition, Fourier imaging, image reconstruction, contrast, signal, and noise.

The second part of the text explores MRI methods and applications, including fast imaging, water-fat separation, steady state gradient echo imaging, echo planar imaging. Cite this chapter as: Schultz G. () Overview of PatLoc Imaging and Presentation of Initial Hardware Designs. In: Magnetic Resonance Imaging with Nonlinear Gradient Fields.

The goal of magnetic resonance (MR) imaging is not only to establish the presence of different nuclei, but also to determine the spatial distribution of a given species within the sample. To impose spatial dependence, the uniform static field can be augmented by a smaller, linearly varying magnetic field.

1 Magnetic Resonance Imaging: A Preview 1. Magnetic Resonance Imaging: The Name 1. The Origin of Magnetic Resonance Imaging 2. A Brief Overview of MRI Concepts 3. 2 Classical Response of a Single Nucleus to a Magnetic Field Magnetic Moment in the Presence of a Magnetic Field Magnetic Moment with Spin: Equation of.

Magnetic Resonance Imaging. Magnetic Field Gradients. As has been shown in Sectionthe fundamental equation of magnetic resonance is the Larmor equation. In an NMR experiment a measurement of the frequency of precession of the magnetisation gives information on the field experienced by that group of spins.

We present a method to correct intensity variations and voxel shifts caused by non-linear gradient fields in magnetic resonance images. The principal sources of distortion are briefly discussed, as well as the methods of correction currently in use. The implication of the gradient field non-linearities on the signal equations are described in a detailed way for the case of two- and three.

One embodiment of the present invention is a method for nuclear magnetic resonance imaging of an investigation region of formation surrounding a wellbore. The method comprises the steps of applying a series of magnetic field gradients to phase encode nuclear spins within the investigation region, wherein the strength of the magnetic field gradient applied is different from at least one.

Abstract: This tutorial explains how magnetic resonance imaging (MRI) systems use the reaction of hydrogen atoms moving in a magnetic field to yield a detailed medical image. The types of magnetic fields typically used are described. The note explains why today's higher resolution MRI systems rely on super-conducting magnets.

Monoplanar gradient system for imaging with nonlinear gradients. Encoding fields generated by the prototype encoding system were shown to be locally orthogonal and able to encode a cylindrical volume sufficient for some abdomen imaging applications for humans.

Magnetic Resonance Imaging/methods; Nonlinear Dynamics. Due to engineering limitations, the spatial encoding gradient fields in conventional magnetic resonance imaging cannot be perfectly linear and always contain higher-order, nonlinear components.

If ignored during image reconstruction, gradient nonlinearity (GNL) manifests as image geometric distortion. Time-varying magnetic field gradients in MR systems provide position-dependent variation in magnetic field strength. The gradients are pulsed and the faster the sequence of imaging, the greater the gradient fields change rate.

The main concerns associated with time-varying magnetic fields are biological effects and acoustic noise. Electromagnetic Analysis and Design in Magnetic Resonance Imaging is unique in its detailed examination of the analysis and design of the hardware for an MRI system.

It takes an engineering perspective to serve the many scientists and engineers in this rapidly expanding field. How The Development of Magnetic Resonance Imaging (MRI) Illustrates What’s Possible With Magnetic Fields. The breakthrough in the discovery of both the MRI for imaging and Q Magnets for pain relief is found in magnetic field gradients.

While the MRI is a state-of-the-art diagnostic instrument, its story shows how gradient modulated magnetic fields can be [ ]. We present a method to correct intensity variations and voxel shifts caused by non-linear gradient fields in magnetic resonance images.

The principal sources of distortion are briefly discussed, as well as the methods of correction currently in use. The implication of the gradient field non-linearit .Follow Medical Imaging and Technology Alliance (MITA), A division of NEMA This standard has been rescinded and is no longer for sale on the NEMA website.

If needed, please contact Techstreet at ()or () (outside the U.S.) or email [email protected] to inquire about buying historical copies.Joseph P. Hornak, Ph.D. Dr. Hornak is Professor of Chemistry and Imaging Science at the Rochester Institute of Technology where he teaches courses in magnetic resonance imaging, nuclear magnetic resonance spectroscopy, analytical chemistry, and physical chemistry.