Ultrasound Technology for Clinical Practitioners

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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.

Author(s): Crispian Oates
Publisher: Wiley
Year: 2023

Language: English
Pages: 378
City: Hoboken

Cover
Title Page
Copyright Page
Contents
Acknowledgments
List of Abbreviations
Introduction
CHAPTER 1 The Basic Physics of Ultrasound
Sound Waves
Describing Waves
Energy in a Sound Wave
Ultrasound Pulses
Energy Spectrum of a Pulse
Bandwidth
Quality Factor
Speed of Sound (C)
Characteristic Acoustic Impedance, Z0
Energy in a Sound Wave
Decibels
CHAPTER 2 The Interaction of Ultrasound with Tissue
Reflection and Transmission at a Plane Interface
Specular Reflection
Reflection at an Angle and Refraction
Poor Visualisation
Scattering
Total Scattered Power
The Speckle Pattern
Attenuation
Attenuation Coefficient (á)
Summary
The Journey of the Ultrasound Pulse
User Control
Transmit Power
References
CHAPTER 3 Beam Shapes
Simple Beam Shape Model
Huygen’s Wavelet Model and Diffraction
Focusing
Beam Forming with Transducer Arrays
Grating Lobes
Apodization
Beam Steering
Beam Shape and Beam Steering
Electronic Focusing
Resolution
Axial Resolution
Lateral Resolution
Resolution Versus Penetration
Clutter
Reference
CHAPTER 4 The Ultrasound Probe
The Transducer
Piezoelectric Effect
Single Crystal Technology
Resonant Frequency
Backing Layer
Matching Layer
Front Face Lens
Wide Band Transducers
Construction of an Array
CMUT Technology
1-D, 1.5-D, and 2-D Arrays
The Hanafy Lens
1.5-D Array
2-D Array
References
CHAPTER 5 Image Formation
Image Modes
A-Mode (Amplitude Mode)
M-Mode (Motion Mode)
B-Mode or Greyscale Image (Brightness Mode)
Linear Image Formation
Linear Array
Frame Rate
Curvilinear Array
Phased Array
Extended Field of View
Panoramic View
3D Imaging
Hand Scanning
Mechanical 3D Probe
2D Matrix Array
3D Image Display
Cine Loop
Endoprobes
Choosing A Probe
Focusing
Transmit Focus
Receive Focus
Increasing Frame Rate
Synthetic Aperture Imaging
User Control
Resolution/Penetration
Ultrasound Harmonics
Harmonic Imaging
Pros and Cons of Harmonic Imaging
Coded Excitation
References
CHAPTER 6 The B-Mode Scanner
Transmission Side of a Scanner
Beam Former
PRF – Pulse Repetition Frequency
User Controls
Transmit Power
Depth of Focus
Receive Side of a Scanner (RX)
Beam Former
Gain
User Controls – Gain
Time Gain Compensation
Analogue to Digital Converter – ADC
Advantages of Digitising
Echo Detection
Dynamic Range and Transfer Function (Greyscale Mapping)
Dynamic Range
Transfer Function or Grey Scale Mapping
Contrast Resolution
User Controls
Image Memory
Frame Freeze
Read and Write Zoom
Read Zoom
Write Zoom
Image Processing
User Control
Exam Presets
Measurements
CHAPTER 7 Image Quality and Artefacts
Acoustic Window
Frame Rate: Frames Per Second (fps)
Interlacing Scan Lines
Interpolation – Writing in ‘Extra Lines’
Speckle
Frame Averaging or Persistence
User Control
Spatial Compound Imaging
Adaptive Filtering
Edge Enhancement
Contrast Resolution
Noise in an Image
Colour Enhancement of Greyscale Images
Human Visual Perception
How to Set Up a Monitor
Image Flicker
Ambient Lighting
Artefacts
Assumptions
Speed of Sound Artefacts
Refraction
Axial Misplacement
Attenuation Artefacts
Poorly Adjusted Time Gain Control (TGC)
Acoustic Shadowing
Post Cystic Enhancement
Shadowing from the Transducer Surface
Reflection Artefacts
Mirror Image Artefact
Reverberation
Reverberation Artefact
Probe – Interface Reverberation
Ringdown
Comet Tail or Ringing
Anisotropy
Beam Shape Artefacts
Slice Thickness Artefact
Side Lobes and Grating Lobes
Temporal Artefacts
Image Blurring
Final Example
References
CHAPTER 8 Principles of Doppler Ultrasound
The Doppler Effect
The Doppler Equation
Duplex Ultrasound
CW Doppler
Block Diagram of CW Doppler Instrument
Detection of Direction of Flow
The Doppler Waveform Display (Sonogram)
Examples
1. Slowly Moving Blood Flow in a Vessel
2. Fast Moving Blood Flow in a Vessel
CW Doppler Summary
Pulsed Wave Doppler (PW Doppler) and Range Gating
Detection of the Doppler Signal
Block Diagram of Pulsed Doppler Instrument with Sonogram Display
Aliasing
Appearance of Aliasing on the Sonogram
Observing Low Velocities
PW Doppler Summary
The PW Doppler Pulses
Intrinsic Spectral Broadening (ISB)
Question: What Doppler Angle Should We Use?
User Controls
Angle Correction
Doppler Beam Steering
Length and Depth of Sample Volume
Scale
Sweep Speed
Baseline Offset and Invert
Doppler Transmit Power
Doppler Gain
Peak Velocity Envelope
Autotrace
Average Velocity
Doppler Artefacts
Aliasing
Intrinsic Spectral Broadening
Wall Thump
User Control
Waveform Ghosting
Shadowing
References
CHAPTER 9 Principles of Colour Doppler Ultrasound
Autocorrelation
Colour Scale
Frame Rate
User Controls
Colour Box
Frame Averaging
Sampling
CDU and the Doppler Angle
Colour Aliasing
User Controls
Scale
Invert
Discrimination of Stationary Targets
Imaging Small Vessels
User Controls
Wall Filter
B-Mode Priority
Power Doppler (PD)
CDU Artefacts
Aliasing
Shadowing
Wall Discrimination
Flash Artefact
Mirror Image
Twinkle Artefact
Temporal Artefact
Colour Sensitivity
Presets
Colour M-Mode
Tissue Doppler Imaging (TDI)
Myocardial Strain Imaging
Strain
Strain Rate (SR)
Using TDI to Measure Strain
Speckle Tracking Echocardiography STE
STE Display
References
CHAPTER 10 Making Measurements
Accuracy
Precision
How Accurate or Precise Do We Need To Be?
Reproducibility
Systematic and Random Errors
Random Errors
Ultrasound Measurements in Practice
Physical Constraints
Scaling
Caliper Accuracy
Image Resolution
Sonographer-Based Constraints
Principles for Making Reliable Measurements
Target Visualisation
Frame Freeze
Use First Interface
Measurements Protocols
Actual Measurements
Factoring Variability
Ultrafine Measurements
Measurement of Circumference, Area, and Volume
Direct Measurement
Assume a Simple Shape
Use a Simplified Model of the Target
Slicing Models
Surface Segmentation and Automated Methods
Doppler Waveform Measurements
Image/Sonogram Size
Scale
Gain
Freeze the Image
Weak Signals
Doppler Angle
Waveform Indices
Pulsatility Index (PI)
Resistance Index (RI)
A/B Ratio
Colour Doppler Ultrasound
Measurement of Volume Flow Q
Cross-Section Area A
Average Velocity
References
CHAPTER 11 Safety and Quality Assurance
Energy, Power, and Intensity
Measuring Intensity
Intensity
Factors Affecting Damage Potential
Thermal Effects
Thermal Index (TI)
TIS
TIB
TIC
Transducer Self-Heating
Nonthermal Effects
Radiation Force
Streaming
Cavitation
Mechanical Index (MI)
ALARA
Contrast Agents
Clinical Risk
Bio-effects from Ultrasound
Quality Assurance and Routine Checks
Suggested Routine User Checks
Annual Service
The Use of Test Objects
Personal Risk Management
WRRSI Risk Mitigation
In Summary
New Techniques in Ultrasound
References
CHAPTER 12 Advanced Topics
Contrast Agents (CA)
Behaviour of Bubbles in the Ultrasound Field
Contrast Agent Harmonics
Amplitude Modulation
Pulse Inversion
Flashing
Advanced Micro-Bubble Techniques
B-Flow Blood Vessel Imaging
Doppler Measurement of Pressure Gradients
Advanced Image Processing
Artificial Intelligence
Segmentation
Examples (1–3)
Computer-Aided Diagnosis (CAD)
Feature Identification
Examples
Classification
Deep Learning
Diagnosis with Cad
Examples of CAD
Fusion Imaging
Needle Visualisation and Guidance
References
CHAPTER 13 Ultrafast Ultrasound
Synthetic Aperture Imaging (SA)
Plane-Wave Beamforming
Summary
Speed of Sound Correction
Benefits
Ultrafast Doppler
Ultrafast Colour Doppler (UFCD)
Microvascular Imaging
Pulsed Wave Doppler (PW)
Vector Flow Imaging (VFI)
The Flow Vector
Directional Beam Forming
Transverse Oscillation (TO)
Display of Flow Vectors
Vector Display
Colour Display
References
CHAPTER 14 Elastography
Background Theory
Elastography
Methods of Applying The Distorting Force
Strain Elastography (SE)
SE with Manual or Physiological Palpation
User Controls
Frequency
Frame Rate
Tracking Window
Frame Reject
Noise Reject
Line Density
Frame Averaging
Dynamic Range
Colour Map
Colour Blend
SE Artefacts
Stress Concentration Artefacts
Edge Enhancement Effects
Appearance of Cysts
Blue/Green/Red Artefact
Shadowing
Acoustic Radiation Force Impulse Imaging (ARFI Imaging)
Pros and Cons of ARFI
Strain Ratio
Shear Wave Elastography (SWE)
Background Theory
Point SWE (PSWE)
Supersonic Shear Imaging (SSI)
Shear Wave Compounding
SWE Artefacts
Bang Artefact
References
Appendix 1: Knobology
Appendix 2: Handling Equations and Decibels
Appendix 3: The Unfocused Transducer Beam Shape
Index
EULA