LED-Based Photoacoustic Imaging (eBook)

Foreword 6
Contents 8
About the Editor 10
Fundamentals and Theory 12
Fundamentals of Photoacoustic Imaging: A Theoretical Tutorial 13
1 Introduction 13
2 Theory of Photoacoustic Wave Generation and Propagation 15
2.1 Generation of Photoacoustic Wave (Initial PA-Pressure) 16
2.2 Propagation of Photoacoustic Wave 20
3 Conclusion 24
References 30
High-Power Light Emitting Diodes An Alternative Excitation Source for Photoacoustic Tomography
1 Introduction 32
2 Photoacoustic Tomography 34
3 High-Power LEDs 38
3.1 Characteristics of High-Power LEDs 38
4 Major Areas of Development in LED-Based Photoacoustic Imaging 43
4.1 Single Point Measurements 43
4.2 Photoacoustic Tomography 44
4.3 Photoacoustic Spectroscopy 46
4.4 Novel Excitation Schemes 48
5 Summary and Outlook 48
References 50
Image Enhancement and Reconstruction Techniques 53
Deformation-Compensated Averaging for Deep-Tissue LED and Laser Diode-Based Photoacoustic Imaging Integrated with Handheld Echo Ultrasound 54
1 Introduction 55
2 DCA Prerequisites 57
2.1 US Image Quality 57
2.2 Motion Tracking Algorithm 59
3 Combined Handheld PA and US System 62
3.1 Acquisition System 62
3.2 Image Reconstruction 64
3.3 DCA Details 65
3.4 Image Display 67
4 Results 68
4.1 Illustration of Processing Steps 68
4.2 Further Results 75
5 Discussion and Conclusion 78
References 82
Ultrasound Receive-Side Strategies for Image Quality Enhancement in Low-Energy Illumination Based Photoacoustic Imaging 86
1 Introduction 86
2 Review of Image Enhancement Strategies for PAT Systems 89
2.1 LED-PAUS Imaging System 89
2.2 Effect of Hardware-Based Improvisations Implemented on Ultrasound Transducer for PAT Application 93
3 Sub-pitch Translation for Improving PAT Image Quality 97
3.1 Theory and Methodology 98
3.2 Results and Discussion 105
4 Removal of EMI in Low SNR PAT Images 112
4.1 Methodology 113
4.2 Results 114
5 Conclusion 115
References 116
Vascular Complexity Evaluation Using a Skeletonization Approach and 3D LED-Based Photoacoustic Images 120
1 Introduction 121
2 Blood Vessel Extraction Techniques 122
2.1 Pattern Recognition Techniques 122
2.2 Model-Based Techniques 125
2.3 Vessel Tracking Techniques 126
2.4 Machine Learning 126
3 Vessel Architecture Quantification 126
3.1 Morphological Parameters 128
3.2 Tortuosity Parameters 128
4 Phantom Design 129
4.1 Model Design 129
4.2 Phantoms Realization 131
4.3 Acquisition Setup 131
4.4 Device Settings 132
5 Image Processing and Results 133
5.1 Segmentation and Skeletonization 133
5.2 Parameter Calculation and Validation 134
6 Feasibility Study Results 135
7 Conclusion 136
References 136
Multiscale Signal Processing Methods for Improving Image Reconstruction and Visual Quality in LED-Based Photoacoustic Systems 139
1 Introduction 139
2 Block Diagram of Imaging and Signal Acquisition 141
3 Signal Domain Processing of PA Acquisitions 142
4 Image Processing Applications 147
4.1 Pre-processing and Noise Removal 147
4.2 Segmentation of Objects in PA Images 151
5 Reconstructed PA Image Quality Improvement Using a Multimodal Framework 159
6 Summary 162
References 163
Data Structure Assisted Accelerated Reconstruction Strategy for Handheld Photoacoustic Imaging 165
1 Introduction 166
2 Analytic Equation Based Algorithms 168
2.1 Filtered BackProjection Based PACT Imaging 168
2.2 Time Reversal Based PACT Imaging 169
2.3 F-K Migration Based PACT Imaging 169
3 Model Based Iterative Image Reconstruction Algorithms 175
3.1 Symmetry Conjugate Gradient Search (CGS) and Least Square Conjugate Gradient Search (LSCGS) Based Reconstruction 178
3.2 Pseudo-dynamical Systems Approach for PACT Imaging 178
4 Numerical Phantom Experiment 182
5 Discussion and Conclusions 184
References 185
Democratizing LED-Based Photoacoustic Imaging with Adaptive Beamforming and Deep Convolutional Neural Network 188
1 Introduction 189
2 Image Reconstruction from Post-beamformed RF Data 190
2.1 Problem Statement 190
2.2 Technical Approach 191
2.3 Simulation Evaluation 194
2.4 Experimental Demonstration 195
2.5 Discussion 196
3 SNR Enhancement with Convolutional Neural Network 198
3.1 Problem Statement 198
3.2 Deep Convolutional Neural Network 199
3.3 Experimental Demonstration 200
3.4 Discussion 203
4 Conclusions and Future Directions 203
References 204
Deep Learning for Image Processing and Reconstruction to Enhance LED-Based Photoacoustic Imaging 208
1 Introduction 208
1.1 Photoacoustic Imaging 208
1.2 Photoacoustic Image Acquisition and Reconstruction 210
1.3 Types of Artifact 212
1.4 LED Based Photoacoustic Imaging 213
2 Machine Learning and Artificial Intelligence 215
2.1 Neural Networks 216
2.2 Convolution Neural Network 217
2.3 Learning by Neural Networks 218
2.4 Backpropagation 221
2.5 Improving the Networks Performance 221
2.6 Evaluation Indices 222
2.7 Training Data 223
2.8 Neural Networks for Medical Imaging 223
3 Monte Carlo Simulation 229
4 Applications of Deep Learning in Photoacoustic Imaging 231
4.1 Deep Learning for LED Based Photoacoustic Imaging 234
5 Limitations of Deep Learning 237
6 Future Directions for Deep Learning 239
7 Conclusion 239
References 240
Preclinical Applications, Clinical Translation, Trends and Challenges 247
Light Emitting Diodes Based Photoacoustic and Ultrasound Tomography: Imaging Aspects and Applications 248
1 Introduction 249
2 Tomographic Imaging Using Linear Array 250
3 Imaging Aspects Using a Linear Array 251
3.1 Transducer Characterization 251
3.2 Optimal Number of Angular Views 253
3.3 Tomographic Image Reconstruction 255
3.4 Resolution Improvement 255
4 LED-Based Illumination for Tomography 256
4.1 Imaging Experiments 260
4.2 Tomographic Imaging Using Top Illumination 260
4.3 Finger Joint Imaging Using Side-Illumination 262
4.4 Tomographic Imaging Speed 265
5 Future Perspectives 265
6 Conclusion 266
References 267
Functional and Molecular Photoacoustic Computed Tomography Using Light Emitting Diodes 270
1 Introduction 270
2 LED-Based PAUS Imaging 272
2.1 Commercial LED-PAUS Imaging System 273
2.2 Capability of LED-PAUS System to Image Exogenous Contrast Agents 273
2.3 Capability of LED PAUS System to Image Labeled Cells in Vivo 274
2.4 LED-PAUS System for Monitoring Angiogenesis in Fibrin Scaffolds 276
2.5 High Speed Photoacoustic Imaging Using LED-PAUS System 280
2.6 Human Placental Vasculature Imaging Using LED-PAUS System 282
2.7 In Vivo Real-Time Oxygen Saturation Imaging Using LED-PAUS System 284
2.8 In Vivo Imaging of Human Lymphatic System Using LED-PAUS System 286
2.9 Multispectral Photoacoustic Characterization Using LED-PAUS System 289
3 LED-Based PACT System 290
3.1 Design of LED-Based PACT System 290
3.2 LED-PACT Data Acquisition and Image Formation 292
3.3 Simulation and Experimental Studies 292
4 Conclusion 301
References 302
LED-Based Functional Photoacoustics—Portable and Affordable Solution for Preclinical Cancer Imaging 306
1 Introduction 306
2 LED Based Photoacoustic Imaging 308
2.1 PAI to Monitor the Tumor Microenvironment 309
2.2 Oxygen Enhanced PAI 311
2.3 PAI to Predict the Tumor Response to Treatment 312
2.4 Contrast Enhancement in PAI Using Nanoparticles 317
3 Future Directions 318
4 Conclusion 319
References 320
LED-Based Photoacoustic Imaging for Guiding Peripheral Minimally Invasive Procedures 323
1 Introduction 324
1.1 Photoacoustic Imaging of Peripheral Vasculature 324
1.2 Applications to Minimally Invasive Procedures 326
2 LED-Based Photoacoustic Imaging of Vasculature 326
3 LED-Based Imaging of Invasive Medical Devices 329
4 Prospects for LED-Based Photoacoustic Imaging of Peripheral Nerves 329
5 Challenges for Clinical Translation 331
6 Conclusion 333
References 333
Application of LED-Based Photoacoustic Imaging in Diagnosis of Human Inflammatory Arthritis 337
1 Introduction 338
2 LED-Based PA Imaging of Subsurface Microvasculature In Vivo: A Feasibility Study 339
2.1 Imaging Microvasculature in 2D and 3D 339
2.2 Arterial Pulsation and Blood Reperfusion 340
2.3 Blood Oxygen Saturation 341
2.4 Imaging of Peripheral Vasculature and Response to Cold Exposure 342
3 LED-Based PA Imaging of Inflammatory Arthritis: A Clinical Study 344
3.1 Introduction of Inflammatory Arthritis 344
3.2 LED-Based PA Imaging in Three Groups of Joints: Clinically Active Arthritis, Subclinically Active Arthritis and Healthy Joints 344
3.3 Statistic Results Based on Imaging 345
4 Future Perspective 347
5 Conclusion 348
References 348
Diagnosis and Treatment Monitoring of Port-Wine Stain Using LED-Based Photoacoustics: Theoretical Aspects and First In-Human Clinical Pilot Study 352
1 Introduction 353
2 Theory 353
2.1 Temperature Field 355
2.2 Displacement Field in Media and Photoacoustic Signal in Liquid 359
2.3 Photoacoustic Signal of PWS 367
3 Clinical Pilot Study 370
3.1 Material & Methods
3.2 Results and Discussion 373
4 Summary and Outlook 376
5 Conclusions 377
References 377
Clinical Translation of Photoacoustic Imaging—Opportunities and Challenges from an Industry Perspective 379
1 Introduction 379
2 Commercially Available Photoacoustic Imaging Systems 381
3 Photoacoustic Imaging Technology: Market Trend 382
4 Key Components in a Photoacoustic Imaging System 384
4.1 Optical Source for Tissue Illumination 384
4.2 Ultrasound Detection 386
4.3 Data Acquisition System 386
5 Clinical Translation of Photoacoustic Imaging: Steps, Opportunities and Challenges 387
5.1 Validation Using Preclinical Models 389
5.2 Clinical Studies 390
5.3 Standardization of the Technology 390
6 Conclusions 391
References 392