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Ultrasound Technology for Clinical Practitioners. Edition No. 1

  • Book

  • 384 Pages
  • February 2023
  • John Wiley and Sons Ltd
  • ID: 5837109
Ultrasound Technology for Clinical Practitioners

A hands-on and practical roadmap to ultrasound technology for clinical practitioners who use it every day

In Ultrasound Technology for Clinical Practitioners, distinguished medical physicist and vascular ultrasound scientist Crispian Oates delivers an accessible and practical resource written for the everyday clinical user of ultrasound. The book offers complete descriptions of the latest techniques in ultrasound, including ultrafast ultrasound and elastography, providing an up-to-date and relevant resource for educators, students, and practitioners alike.

Ultrasound Technology for Clinical Practitioners uses a first-person perspective that walks readers through a relevant and memorable story containing necessary information, simplifying retention and learning. It makes extensive use of bulleted lists, diagrams, and images, and relies on mathematics and equations only where necessary to illustrate the relationship between other factors. Physics examples come from commonly known contexts that readers can relate to their everyday lives, and additional description boxes offer optional, helpful info in some topic areas.

Readers will also find: - A thorough introduction to the foundational physics of ultrasound, as well as the propagation of the ultrasound pulse through tissue- Comprehensive discussions of beam shapes, transducers, imaging techniques, and pulse echo instrumentation- In-depth examination of image quality and artefacts and the principles of Doppler and colour Doppler ultrasound- Fulsome treatments of measurement taking and safety and quality assurance in ultrasound

Perfect for sonographers, echocardiographers, and vascular scientists, Ultrasound Technology for Clinical Practitioners will also earn a place in the libraries of radiologists, cardiologists, emergency medicine specialists, and all other clinical users of ultrasound.

Table of Contents

Acknowledgments xvii

List of Abbreviations xix

Introduction 1

Chapter 1 The Basic Physics of Ultrasound 5

Sound Waves 5

Describing Waves 9

Energy in a Sound Wave 11

Ultrasound Pulses 12

Energy Spectrum of a Pulse 13

Bandwidth 14

Speed of Sound (C) 16

Characteristic Acoustic Impedance, Z0 20

Energy in a Sound Wave 22

Decibels 23

Chapter 2 The Interaction of Ultrasound with Tissue 25

Reflection and Transmission at a Plane Interface 25

Poor Visualisation 29

Scattering 30

Attenuation 34

The Journey of the Ultrasound Pulse 37

User Control 37

References 38

Chapter 3 Beam Shapes 39

Simple Beam Shape Model 40

Huygen’s Wavelet Model and Diffraction 43

Focusing 44

Beam Forming with Transducer Arrays 47

Beam Steering 50

Electronic Focusing 52

Resolution 54

Clutter 58

Reference 58

Chapter 4 The Ultrasound Probe 59

The Transducer 59

Backing Layer 62

Matching Layer 63

Front Face Lens 65

Wide Band Transducers 65

Construction of an Array 66

CMUT Technology 66

1-D, 1.5-D, and 2-D Arrays 68

References 72

Chapter 5 Image Formation 73

Image Modes 74

Linear Image Formation 76

3D Imaging 80

Cine Loop 82

Endoprobes 82

Choosing A Probe 84

Focusing 84

Increasing Frame Rate 86

User Control 86

Ultrasound Harmonics 89

Coded Excitation 92

References 94

Chapter 6 The B-Mode Scanner 95

Transmission Side of a Scanner 95

User Controls 96

Receive Side of a Scanner (Rx) 97

Advantages of Digitising 101

Dynamic Range and Transfer Function (Greyscale Mapping) 102

Contrast Resolution 106

User Controls 106

Image Memory 106

Frame Freeze 106

Read and Write Zoom 107

Image Processing 108

User Control 108

Chapter 7 Image Quality and Artefacts 111

Acoustic Window 111

Frame Rate: Frames Per Second (fps) 112

Interlacing Scan Lines 113

Interpolation - Writing in ‘Extra Lines’ 114

Speckle 115

Frame Averaging or Persistence 116

User Control 117

Spatial Compound Imaging 117

Adaptive Filtering 118

Artefacts 122

Speed of Sound Artefacts 122

Attenuation Artefacts 127

Reflection Artefacts 130

Anisotropy 134

Beam Shape Artefacts 135

Temporal Artefacts 137

Final Example 139

References 140

Chapter 8 Principles of Doppler Ultrasound 141

The Doppler Effect 141

The Doppler Equation 143

Duplex Ultrasound 144

CW Doppler 145

CW Doppler Summary 152

Pulsed Wave Doppler (PW Doppler) and Range Gating 152

Intrinsic Spectral Broadening (ISB) 160

Question: What Doppler Angle Should We Use? 162

User Controls 163

Peak Velocity Envelope 165

Average Velocity 167

Doppler Artefacts 170

References 173

Chapter 9 Principles of Colour Doppler Ultrasound 175

Autocorrelation 177

Colour Scale 180

Frame Rate 181

User Controls 181

CDU and the Doppler Angle 183

Colour Aliasing 183

User Controls 185

Discrimination of Stationary Targets 187

User Controls 188

Power Doppler (PD) 188

CDU Artefacts 190

Colour Sensitivity 192

Presets 194

Colour M-Mode 194

Tissue Doppler Imaging (TDI) 194

Myocardial Strain Imaging 197

Speckle Tracking Echocardiography STE 199

References 202

Chapter 10 Making Measurements 203

Accuracy 204

Precision 204

How Accurate or Precise Do We Need To Be? 205

Reproducibility 205

Systematic and Random Errors 206

Ultrasound Measurements in Practice 206

Physical Constraints 207

Sonographer-Based Constraints 209

Principles for Making Reliable Measurements 209

Measurement of Circumference, Area, and Volume 213

Doppler Waveform Measurements 216

Waveform Indices 219

Colour Doppler Ultrasound 221

Measurement of Volume Flow Q 221

References 224

Chapter 11 Safety and Quality Assurance 225

Energy, Power, and Intensity 226

Measuring Intensity 227

Intensity 227

Factors Affecting Damage Potential 230

Thermal Effects 231

Thermal Index (TI) 232

Transducer Self-Heating 234

Nonthermal Effects 235

Radiation Force 235

Streaming 235

Cavitation 236

Mechanical Index (MI) 239

Alara 239

Contrast Agents 240

Quality Assurance and Routine Checks 241

Suggested Routine User Checks 241

The Use of Test Objects 244

Personal Risk Management 245

New Techniques in Ultrasound 246

References 247

Chapter 12 Advanced Topics 249

Contrast Agents (CA) 249

Behaviour of Bubbles in the Ultrasound Field 251

Contrast Agent Harmonics 252

Flashing 254

Advanced Micro-Bubble Techniques 255

B-Flow Blood Vessel Imaging 256

Doppler Measurement of Pressure Gradients 260

Advanced Image Processing 261

Artificial Intelligence 261

Segmentation 262

Examples (1-3) 262

Computer-Aided Diagnosis (CAD) 263

Diagnosis with Cad 268

Fusion Imaging 269

Needle Visualisation and Guidance 271

References 274

Chapter 13 Ultrafast Ultrasound 277

Synthetic Aperture Imaging (SA) 278

Plane-Wave Beamforming 279

Summary 283

Speed of Sound Correction 283

Ultrafast Doppler 286

Vector Flow Imaging (VFI) 291

References 298

Chapter 14 Elastography 301

Background Theory 302

Elastography 303

Methods of Applying The Distorting Force 303

Strain Elastography (SE) 303

User Controls 307

SE Artefacts 310

Acoustic Radiation Force Impulse Imaging (ARFI Imaging) 314

Strain Ratio 316

Shear Wave Elastography (SWE) 316

Point SWE (PSWE) 320

Supersonic Shear Imaging (SSI) 322

Shear Wave Compounding 323

SWE Artefacts 325

References 326

Appendix 1: Knobology 329

Appendix 2: Handling Equations and Decibels 335

Appendix 3: The Unfocused Transducer Beam Shape 345

Index 349

Authors

Crispian Oates Newcastle University, UK.