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E-raamat: Magnetic Resonance Elastography - Physical Background and Medical Applications: Physical Background and Medical Applications [Wiley Online]

  • Formaat: 456 pages
  • Ilmumisaeg: 11-Jan-2017
  • Kirjastus: Blackwell Verlag GmbH
  • ISBN-10: 3527696016
  • ISBN-13: 9783527696017
  • Wiley Online
  • Hind: 185,03 €*
  • * hind, mis tagab piiramatu üheaegsete kasutajate arvuga ligipääsu piiramatuks ajaks
  • Formaat: 456 pages
  • Ilmumisaeg: 11-Jan-2017
  • Kirjastus: Blackwell Verlag GmbH
  • ISBN-10: 3527696016
  • ISBN-13: 9783527696017
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.
About the Authors xiii
Foreword xv
Preface xvii
Acknowledgments xix
Notation xxi
List of Symbols
xxiii
Introduction 1(6)
Part I Magnetic Resonance Imaging
7(54)
1 Nuclear Magnetic Resonance
9(14)
1.1 Protons in a Magnetic Field
9(1)
1.2 Precession of Magnetization
10(3)
1.2.1 Quadrature Detection
11(2)
1.3 Relaxation
13(1)
1.4 Bloch Equations
14(1)
1.5 Echoes
15(2)
1.5.1 Spin Echoes
15(2)
1.5.2 Gradient Echoes
17(1)
1.6 Magnetic Resonance Imaging
17(6)
1.6.1 Spatial Encoding
18(1)
1.6.1.1 Slice Selection
19(1)
1.6.1.2 Phase Encoding
19(1)
1.6.1.3 Frequency Encoding
20(3)
2 Imaging Concepts
23(18)
2.1 k-Space
23(3)
2.2 k-Space Sampling Strategies
26(7)
2.2.1 Segmented Image Acquisition
27(1)
2.2.1.1 Fast Low-Angle Shot (FLASH)
27(1)
2.2.1.2 Balanced Steady-State Free Precession (bSSFP)
28(2)
2.2.2 Echo-Planar Imaging (EPI)
30(2)
2.2.3 Non-Cartesian Imaging
32(1)
2.3 Fast Imaging
33(8)
2.3.1 Fast Imaging Strategies
33(1)
2.3.2 Partial Fourier Imaging
34(1)
2.3.3 Parallel Imaging
35(1)
2.3.3.1 GRAPPA
36(1)
2.3.4 Impact of Fast Imaging on SNR and Scan Time
37(4)
3 Motion Encoding and MRE Sequences
41(20)
3.1 Motion Encoding
43(14)
3.1.1 Gradient Moment Nulling
44(2)
3.1.2 Encoding of Time-Harmonic Motion
46(4)
3.1.3 Fractional Encoding
50(1)
3.2 Intra-Voxel Phase Dispersion
51
3.3 Diffusion-Weighted MRE
52(1)
3.4 MRE Sequences
53(8)
3.4.1 FLASH-MRE
53(2)
3.4.2 bSSFP-MRE
55(2)
3.4.3 EPI-MRE
57(4)
Part II Elasticity
61(84)
4 Viscoelastic Theory
63(68)
4.1 Strain
63(4)
4.2 Stress
67(1)
4.3 Invariants
68(1)
4.4 Hooke's Law
69(1)
4.5 Strain-Energy Function
70(1)
4.6 Symmetries
71(4)
4.7 Engineering Constants
75(5)
4.7.1 Young's Modulus and Poisson's Ratio
75(1)
4.7.2 Shear Modulus and Lame's First Parameter
76(1)
4.7.3 Compressibility and Bulk Modulus
77(2)
4.7.4 Compliance and Elasticity Tensor for a Transversely Isotropic Material
79(1)
4.8 Viscoelastic Models
80(12)
4.8.1 Elastic Model: Spring
81(1)
4.8.2 Viscous Model: Dashpot
82(1)
4.8.3 Combinations of Elastic and Viscous Elements
83(6)
4.8.4 Overview of Viscoelastic Models
89(3)
4.9 Dynamic Deformation
92(12)
4.9.1 Balance of Momentum
92(4)
4.9.2 Mechanical Waves
96(2)
4.9.2.1 Complex Moduli and Wave Speed
98(1)
4.9.3 Navier--Stokes Equation
99(1)
4.9.4 Compression Modulus and Oscillating Volumetric Strain
100(1)
4.9.5 Elastodynamic Green's Function
101(2)
4.9.6 Boundary Conditions
103(1)
4.10 Waves in Anisotropic Media
104(6)
4.10.1 The Christoffel Equation
105(1)
4.10.2 Waves in a Transversely Isotropic Medium
106(4)
4.11 Energy Density and Flux
110(4)
4.11.1 Geometric Attenuation
113(1)
4.12 Shear Wave Scattering from Interfaces and Inclusions
114(17)
4.12.1 Plane Interfaces
115(3)
4.12.2 Spatial and Temporal Interfaces
118(3)
4.12.3 Wave Diffusion
121(4)
4.12.3.1 Green's Function of Waves and Diffusion Phenomena
125(1)
4.12.3.2 Amplitudes and Intensities of Diffusive Waves
126(5)
5 Poroelasticity
131(14)
5.1 Navier's Equation for Biphasic Media
133(9)
5.1.1 Pressure Waves in Poroelastic Media
136(4)
5.1.2 Shear Waves in Poroelastic Media
140(2)
5.2 Poroelastic Signal Equation
142(3)
Part III Technical Aspects and Data Processing
145(98)
6 MRE Hardware
147(14)
6.1 MRI Systems
147(6)
6.2 Actuators
153(8)
6.2.1 Technical Requirements
153(1)
6.2.2 Practicality
153
6.2.3 Types of Mechanical Transducers
154(7)
7 MRE Protocols
161(4)
8 Numerical Methods and Postprocessing
165(26)
8.1 Noise and Denoising in MRE
165(11)
8.1.1 Denoising: An Overview
165(2)
8.1.2 Least Squares and Polynomial Fitting
167(1)
8.1.3 Frequency Domain (k-Space) Filtering
168(1)
8.1.3.1 Averaging
168(2)
8.1.3.2 LTI Filters in the Fourier Domain
170(2)
8.1.3.3 Band-Pass Filtering
172(1)
8.1.4 Wavelets and Multi-Resolution Analysis (MRA)
172(2)
8.1.5 FFT versus MRA in vivo
174(1)
8.1.6 Sparser Approximations and Performance Times
175(1)
8.2 Directional Filters
176(3)
8.3 Numerical Derivatives
179(8)
8.3.1 Matrix Representation of Derivative Operators
182(1)
8.3.2 Anderssen Gradients
183(3)
8.3.3 Frequency Response of Derivative Operators
186(1)
8.4 Finite Differences
187(4)
9 Phase Unwrapping
191(8)
9.1 Flynn's Minimum Discontinuity Algorithm
193(2)
9.2 Gradient Unwrapping
195(1)
9.3 Laplacian Unwrapping
196(3)
10 Viscoelastic Parameter Reconstruction Methods
199(30)
10.1 Discretization and Noise
201(3)
10.2 Phase Gradient
204(1)
10.3 Algebraic Helmholtz Inversion
205(3)
10.3.1 Multiparameter Inversion
207(1)
10.3.2 Helmholtz Decomposition
207(1)
10.4 Local Frequency Estimation
208(2)
10.5 Multifrequency Inversion
210(4)
10.5.1 Reconstruction of φ
211(2)
10.5.2 Reconstruction of |G*|
213(1)
10.6 k-MDEV
214(3)
10.7 Finite Element Method
217(7)
10.7.1 Weak Formulation of the One-Dimensional Wave Equation
218(1)
10.7.2 Discretization of the Problem Domain
219(1)
10.7.3 Basis Function in the Discretized Domain
220(1)
10.7.4 FE Formulation of the Wave Equation
221(3)
10.8 Direct Inversion for a Transverse Isotropic Medium
224(1)
10.9 Waveguide Elastography
225(4)
11 Multicomponent Acquisition
229(4)
12 Ultrasound Elastography
233(10)
12.1 Strain Imaging (SI)
235(1)
12.2 Strain Rate Imaging (SRI)
235(1)
12.3 Acoustic Radiation Force Impulse (ARFI) Imaging
235(2)
12.4 Vibro-Acoustography (VA)
237(1)
12.5 Vibration-Amplitude Sonoelastography (VA Sono)
237(1)
12.6 Cardiac Time-Harmonic Elastography (Cardiac THE)
237(1)
12.7 Vibration Phase Gradient (PG) Sonoelastography
238(1)
12.8 Time-Harmonic Elastography (1D/2D THE)
238(1)
12.9 Crawling Waves (CW) Sonoelastography
238(1)
12.10 Electromechanical Wave Imaging (EWI)
239(1)
12.11 Pulse Wave Imaging (PWI)
239(1)
12.12 Transient Elastography (TE)
240(1)
12.13 Point Shear Wave Elastography (pSWE)
240(1)
12.14 Shear Wave Elasticity Imaging (SWEI)
240(1)
12.15 Comb-Push Ultrasound Shear Elastography (CUSE)
241(1)
12.16 Supersonic Shear Imaging (SSI)
241(1)
12.17 Spatially Modulated Ultrasound Radiation Force (SMURF)
241(1)
12.18 Shear Wave Dispersion Ultrasound Vibrometry (SDUV)
241(1)
12.19 Harmonic Motion Imaging (HMI)
242(1)
Part IV Clinical Applications
243(108)
13 MRE of the Heart
245(18)
13.1 Normal Heart Physiology
245(5)
13.1.1 Cardiac Fiber Anatomy
247(2)
13.1.2 Wall Shear Modulus versus Cavity Pressure
249(1)
13.2 Clinical Motivation for Cardiac MRE
250(2)
13.2.1 Systolic Dysfunction versus Diastolic Dysfunction
250(2)
13.3 Cardiac Elastography
252(11)
13.3.1 Ex vivo SWI
253(1)
13.3.2 In vivo SDUV
253(1)
13.3.3 In vivo Cardiac MRE in Pigs
254(2)
13.3.4 In vivo Cardiac MRE in Humans
256(1)
13.3.4.1 Steady-State MRE (WAV-MRE)
256(3)
13.3.4.2 Wave Inversion Cardiac MRE
259(1)
13.3.5 MRE of the Aorta
260(3)
14 MRE of the Brain
263(20)
14.1 General Aspects of Brain MRE
264(1)
14.1.1 Objectives
264(1)
14.1.2 Determinants of Brain Stiffness
264(1)
14.1.3 Challenges for Cerebral MRE
264(1)
14.2 Technical Aspects of Brain MRE
265(12)
14.2.1 Clinical Setup for Cerebral MRE
265(1)
14.2.2 Choice of Vibration Frequency
266(3)
14.2.3 Driver-Free Cerebral MRE
269(1)
14.2.4 MRE in the Mouse Brain
270(7)
14.3 Findings
277(6)
14.3.1 Brain Stiffness Changes with Age
272(1)
14.3.2 Male Brains Are Softer than Female Brains
273(1)
14.3.3 Regional Variation in Brain Stiffness
274(1)
14.3.4 Anisotropic Properties of Brain Tissue
274(2)
14.3.5 The in vivo Brain Is Compressible
276(1)
14.3.6 Preliminary Findings of MRE with Functional Activation
277(1)
14.3.7 Demyelination and Inflammation Reduce Brain Stiffness
277(2)
14.3.8 Neurodegeneration Reduces Brain Stiffness
279(1)
14.3.9 The Number of Neurons Correlates with Brain Stiffness
280(1)
14.3.10 Preliminary Conclusions on MRE of the Brain
280(3)
15 MRE of Abdomen, Pelvis, and Intervertebral Disc
283(42)
15.1 Liver
283(28)
15.1.1 Epidemiology of Chronic Liver Diseases
286(1)
15.1.2 Liver Fibrosis
287(2)
15.1.2.1 Pathogenesis of Liver Fibrosis
289(2)
15.1.2.2 Staging of Liver Fibrosis
291
15.1.2.3 Noninvasive Screening Methods for Liver Fibrosis
292(1)
15.1.2.4 Reversibility of Liver Fibrosis
293(1)
15.1.2.5 Biophysical Signs of Liver Fibrosis
293(1)
15.1.3 MRE of the Liver
294(1)
15.1.3.1 MRE in Animal Models of Hepatic Fibrosis and Liver Tissue Samples
294(1)
15.1.3.2 Early Clinical Studies and Further Developments
295(8)
15.1.3.3 MRE of Nonalcoholic Fatty Liver Disease
303(1)
15.1.3.4 Comparison with other Noninvasive Imaging and Serum Biomarkers
304(3)
15.1.3.5 MRE of the Liver for Assessing Portal Hypertension
307(2)
15.1.3.6 MRE in Liver Grafts
309(1)
15.1.3.7 Confounders
310(1)
15.2 Spleen
311(3)
15.2.1 MRE of the Spleen
311(3)
15.3 Pancreas
314(1)
15.3.1 MRE of the Pancreas
315(1)
15.4 Kidneys
315(3)
15.4.1 MRE of the Kidneys
316(2)
15.5 Uterus
318(1)
15.5.1 MRE of the Uterus
318(1)
15.6 Prostate
319(2)
15.6.1 MRE of the Prostate
320(1)
15.7 Intervertebral Disc
321(4)
15.7.1 MRE of the Intervertebral Disc
322(3)
16 MRE of Skeletal Muscle
325(8)
16.1 In vivo MRE of Healthy Muscles
326(4)
16.2 MRE in Muscle Diseases
330(3)
17 Elastography of Tumors
333(18)
17.1 Micromechanical Properties of Tumors
333(3)
17.2 Ultrasound Elastography of Tumors
336(3)
17.2.1 Ultrasound Elastography in Breast Tumors
337(1)
17.2.2 Ultrasound Elastography in Prostate Cancer
338(1)
17.3 MRE of Tumors
339(12)
17.3.1 MRE of Tumors in the Mouse
340(2)
17.3.2 MRE in Liver Tumors
342(2)
17.3.3 MRE of Prostate Cancer
344(1)
17.3.3.1 Ex Vivo Studies
344(1)
17.3.3.2 In Vivo Studies
345(1)
17.3.4 MRE of Breast Tumors
345(1)
17.3.4.1 In Vivo MRE of Breast Tumors
346(1)
17.3.5 MRE of Intracranial Tumors
347(4)
Part V Outlook
351(4)
Dimensionality
351(1)
Sparsity
352(1)
Heterogeneity
353(1)
Reproducibility
353(2)
A Simulating the Bloch Equations
355(2)
B Proof that Eq. (3.8) Is Sinusoidal
357(2)
C Proof for Eq. (4.1)
359(2)
D Wave Intensity Distributions
361(6)
D.1 Calculation of Intensity Probabilities
361(1)
D.2 Point Source in 3D
362(1)
D.3 Classical Diffusion
363(2)
D.4 Damped Plane Wave
365(2)
References 367(50)
Index 417
Ingolf Sack is professor for Experimental Radiology and Elastography at Charité - Universitätsmedizin Berlin, Germany. He received a PhD in Chemistry at Freie Universität Berlin, Germany, for the development of methods in NMR spectroscopy. He worked at the Weizmann Institute in Rehovot, Israel, and at the Sunnybrook Hospital Toronto, Canada. Since 2003 he leads an interdisciplinary team of physicists, engineers, chemists and physicians which has pioneered pivotal developments in time-harmonic elastography of both MRI and ultrasound for many medical applications.

Sebastian Hirsch is a postdoctoral fellow in the Department of Radiology at the Charité - Universitätsmedizin Berlin, Germany. After studying physics at the University of Mainz, Germany, he joined Charité, where he works on pressure-sensitive MRE and the development of data acquisition strategies.

Jürgen Braun is an assistant professor at the Charité - Universitätsmedizin Berlin, Germany. He received his PhD degree in physical chemistry from Albert-Ludwigs-University in Freiburg, Germany, for the elucidation of reaction kinetics with liquid and solid state NMR. He possesses long standing professional experience in elastography, medical engineering, and image processing.