Diagnostic ultrasound : imaging and blood flow measurements / K. Kirk Shung

Chapter 1 Introduction ..........................................................................................1 1.1 History..............................................................................................................1 1.2 Role of Ultrasound in Medical Imaging .........................................................2 1.3 Purpose of the Book ........................................................................................3 Reference ...................................................................................................................3 Further Reading .........................................................................................................3 Chapter 2 Fundamentals of Acoustic Propagation ...............................................5 2.1 Stress and Strain Relationships .......................................................................8 2.2 Acoustic Wave Equation ................................................................................11 2.2.1 Compressional Wave..........................................................................11 2.2.2 Shear Wave.........................................................................................12 2.3 Characteristic Impedance...............................................................................13 2.4 Intensity ..........................................................................................................14 2.5 Radiation Force ..............................................................................................17 2.6 Reflection and Refraction ..............................................................................17 2.7 Attenuation, Absorption, and Scattering .......................................................20 2.7.1 Attenuation .........................................................................................21 2.7.2 Absorption..........................................................................................21 2.7.3 Scattering............................................................................................25 2.8 Nonlinearity Parameter B/A ..........................................................................32 2.9 Doppler Effect ................................................................................................35 References................................................................................................................36 Chapter 3 Ultrasonic Transducers and Arrays....................................................39 3.1 Piezoelectric Effect ........................................................................................39 3.2 Piezoelectric Constitutive Equation...............................................................41 3.3 Ultrasonic Transducers...................................................................................46 3.4 Mechanical Matching.....................................................................................53 3.5 Electrical Matching ........................................................................................55 3.6 Transducer Beam Characteristics ..................................................................55 3.6.1 Beam Profiles .....................................................................................57 3.6.2 Pulsed Ultrasonic Field......................................................................61 3.6.3 Visualization and Mapping of the Ultrasonic Field ..........................62 3.6.4 Axial and Lateral Resolution.............................................................63 3.6.5 Focusing .............................................................................................63 © 2006 by Taylor & Francis Group, LLC 3.7 Arrays .............................................................................................................68 References................................................................................................................77 Chapter 4 Gray-Scale Ultrasonic Imaging .........................................................79 4.1 A (Amplitude)-Mode and B (Brightness)-Mode Imaging ............................79 4.1.1 Resolution of B-Mode Ultrasonic Imaging Systems ........................88 4.1.2 Beam Forming....................................................................................88 4.1.3 Speckle ...............................................................................................90 4.1.4 Image Quality.....................................................................................91 4.1.4.1 Point Spread Function ........................................................92 4.1.4.2 Contrast ...............................................................................92 4.1.4.3 Noises..................................................................................94 4.1.5 Phase Aberration Compensation........................................................94 4.1.6 Clinical Applications..........................................................................94 4.2 M-Mode and C-Mode ....................................................................................95 4.3 Ultrasound Computed Tomography (CT)......................................................97 4.4 Coded Excitation Imaging .............................................................................98 4.5 Compound Imaging........................................................................................99 4.6 Synthetic Aperture Imaging...........................................................................99 References..............................................................................................................101 Chapter 5 Doppler Flow Measurements...........................................................103 5.1 Nondirectional CW Flow Meters ................................................................103 5.2 Directional Doppler Flow Meters................................................................108 5.2.1 Single Sideband Filtering.................................................................108 5.2.2 Heterodyne Demodulation ...............................................................109 5.2.3 Quadrature Phase Demodulation .....................................................110 5.3 Pulsed Doppler Flow Meters .......................................................................113 5.4 Clinical Applications and Doppler Indices..................................................115 5.5 Potential Problems in Doppler Measurements ............................................115 5.6 Tissue Doppler and Multigate Doppler .......................................................116 References..............................................................................................................117 Chapter 6 Flow and Displacement Imaging.....................................................119 6.1 Color Doppler Flow Imaging ......................................................................119 6.2 Color Doppler Power Imaging ....................................................................125 6.3 Time-Domain Flow Estimation ...................................................................127 6.4 Elasticity Imaging ........................................................................................129 6.4.1 Elastography.....................................................................................130 6.4.2 Sonoelasticity Imaging.....................................................................131 6.5 B-Flow Imaging ...........................................................................................131 References..............................................................................................................133 © 2006 by Taylor & Francis Group, LLC Chapter 7 Contrast Media and Harmonic Imaging ..........................................135 7.1 Contrast Agents ............................................................................................135 7.1.1 Gaseous Agents ................................................................................135 7.1.2 Encapsulated Gaseous Agents .........................................................139 7.1.3 Dilute Distribution of Bubbles of Varying Size ..............................140 7.2 Nonlinear Interactions between Ultrasound and Bubbles...........................141 7.3 Modified Rayleigh–Plesset Equation for Encapsulated Gas Bubbles .................................................................................................142 7.4 Solutions to Rayleigh–Plesset Equation ......................................................142 7.5 Harmonic Imaging .......................................................................................146 7.6 Native Tissue Harmonic Imaging ................................................................148 7.7 Clinical Applications of Contrast Agents and Harmonic Imaging .............149 References..............................................................................................................150 Chapter 8 Intracavity and High-Frequency (HF) Imaging...............................153 8.1 Imaging.........................................................................................................153 8.1.1 Transesophageal Cardiac Imaging...................................................153 8.1.2 Transrectal and Transvaginal Imaging.............................................155 8.1.3 Endoluminal Imaging.......................................................................156 8.2 Intravascular Imaging...................................................................................157 8.3 High-Frequency Imaging .............................................................................158 8.4 Acoustic Microscopes ..................................................................................162 References..............................................................................................................162 Chapter 9 Multidimensional Imaging...............................................................163 9.1 Parallel Processing .......................................................................................163 9.2 Multidimensional Arrays..............................................................................164 9.2.1 Two-Dimensional Arrays .................................................................166 9.2.2 Sparse Arrays ...................................................................................170 9.3 Three-Dimensional Imaging ........................................................................173 References..............................................................................................................175 Chapter 10 Biological Effects of Ultrasound .....................................................177 10.1 Acoustic Phenomena at High-Intensity Levels ...........................................177 10.1.1 Wave Distortion...............................................................................177 10.1.2 Heating ............................................................................................177 10.1.3 Cavitation ........................................................................................177 10.1.4 Radiation Force and Streaming ......................................................178 10.2 Ultrasound Bioeffects...................................................................................179 10.2.1 Thermal Effects ...............................................................................179 10.2.2 Thermal Index .................................................................................179 10.3 Mechanical Effects and Index .....................................................................180 References..............................................................................................................182 © 2006 by Taylor & Francis Group, LLC Chapter 11 Methods for Measuring Speed, Attenuation, Absorption, and Scattering...................................................................................185 11.1 Velocity.........................................................................................................185 11.1.1 In Vitro Methods .............................................................................185 11.1.1.1 Interferometric Method....................................................185 11.1.1.2 Pulse–Echo Method .........................................................185 11.1.1.3 Velocity Difference Method ............................................187 11.1.2 In Vivo Methods ...............................................................................188 11.2 Attenuation ...................................................................................................190 11.2.1 In Vitro Methods .............................................................................190 11.2.1.1 Transmission Methods .....................................................190 11.2.1.2 Transient Thermoelectric Method ...................................192 11.2.2 In Vivo Methods ..............................................................................194 11.2.2.1 Loss of Amplitude Method..............................................194 11.2.2.2 Frequency Shift Method ..................................................195 11.3 Scattering......................................................................................................195 11.3.1 In Vitro Methods .............................................................................195 11.3.2 In Vivo Methods ..............................................................................201 References..............................................................................................................201 © 2006