Principles and Applications of Magnetic Resonance Elastography

Magnetic resonance elastography (MRE) is a medical imaging technique that combines magnetic resonance imaging (MRI) with mechanical vibrations to generate maps of viscoelastic properties of biological tissue. It serves as a non–invasive tool to detect and quantify mechanical changes in tissue structure, which can be symptoms or causes of various diseases. Clinical and research applications of MRE include staging of liver fibrosis, assessment of tumor stiffness and investigation of neurodegenerative diseases. The first part of this book is dedicated to the physical and technological principles underlying MRE, with an introduction to MRI physics, viscoelasticity theory and classical waves, as well as vibration generation, image acquisition and viscoelastic parameter reconstruction. The second part of the book focuses on clinical applications of MRE to various organs. Each section starts with a discussion of the specific properties of the organ, followed by an extensive overview of clinical and preclinical studies that have been performed, tabulating reference values from published literature. The book is completed by a chapter discussing technical aspects of elastography methods based on ultrasound. INDICE: Foreword. Preface. . Introduction. . PART I. Magnetic Resonance Imaging. . NUCLEAR MAGNETIC RESONANCE. Protons in a Magnetic Field. Precession of Magnetization. Relaxation. Bloch Equations. Echoes. Magnetic Resonance Imaging. . IMAGING CONCEPTS. k–Space. k–Space Sampling Strategies. . MOTION ENCODING AND MRE SEQUENCES. Motion Encoding. Intra–Voxel Phase Dispersion. Diffusion–Weighted MRE. MRE Sequences. . PART II. Elasticity. . VISCOELASTIC THEORY. Strain. Stress. Invariants. Hooke?s Law. Strain–Energy Function. Symmetries. Engineering Constants. Viscoelastic Models. Dynamic Deformation. Waves in Anisotropic Media. Energy Density and Flux. Shear Wave Scattering from Interfaces and Inclusions. . POROELASTICITY. Navier Equations for Biphasic Media. Poroelastic Signal Equation. . PART III. Technical Aspects and Data Processing. . MRE HARDWARE. MRI Systems. Actuators. . MRE PROTOCOLS. . NUMERICAL METHODS AND POST–PROCESSING. Noise and Denoising in MRE. Directional Filters. Numerical Filters. Finite Differences. . PHASE UNWRAPPING. Flynn?s Minimum Discontinuity Algorithm. Gradient Unwrapping. Laplacian Unwrapping. . VISCOELASTIC PARAMETER RECONSTRUCTION METHODS. Discretization and Noise. Phase Gradient. Algebraic Helmholtz Inversion. Local Frequency Estimation. Multifrequency Inversion. k–MDEV. Finite Element Method. Direct Inversion for a Transverse Isotropic Medium. Waveguide Elastography. . MULTI–COMPONENT ACQUISITION. . ULTRASOUND ELASTOGRAPHY. Strain Imaging (SI). Strain–Rate Imaging (SRI). Acoustic Radiation Force Impulse (ARFI) Imaging. Vibro–Acoustography (VA). Vibration–Amplitude Sonoelastography (VA Sono). Cardiac Time–Harmonic Elastography (cardiac THE). Vibration Phase Gradient (PG) Sonoelastography. Time–Harmonic Elastography (1D/2D THE). Crawling Waves (CW) Sonoelastography. Electromechanical Wave Imaging (EWI). Pulse Wave Imaging (PWI). Transient Elastography (TE). Point Shear Wave Elastography (pSWE). Shear Wave Elasticity Imaging (SWEI). Comb–Push Ultrasound Shear Elastography (CUSE). Supersonic Shear Imaging (SSI). Spatially Modulated Ultrasound Radiation Force (SMURF). Shear Wave Dispersion Ultrasound Vibrometry (SDUV). Harmonic Motion Imaging (HMI). . PART IV. Clinical Applications. . MRE OF THE HEART. Normal Heart Physiology. Clinical Motivation for Cardiac MRE. Cardiac Elastography. . MRE OF THE BRAIN. General Aspects of Brain MRE. Technical Aspects of Brain MRE. Findings. . MRE OF ABDOMEN, PELVIS AND INTERVERTEBRAL DISC. Liver. Spleen. Pancreas. Kidneys. Uterus. Prostate. Intervertebral Disc. . MRE OF SKELETAL MUSCLE. In Vivo MRE of Healthy Muscles. MRE in Muscle Diseases. . ELASTOGRAPHY OF TUMORS. Micromechanical Properties of Tumors. Ultrasound Elastography of Tumors. MRE of Tumors. . PART V. Outlook. . APPENDICES. Simulating the Bloch Equations. Proof that eq. (3.8) is Sinusoidal. Proof for eq. (4.1). Wave Intensity Distributions

• ISBN: 978-3-527-34008-8
• Editorial: Wiley VCH
• Encuadernacion: Cartoné
• Páginas: 496
• Fecha Publicación: 28/12/2016
• Nº Volúmenes: 1
• Idioma: Inglés