Practical Signal and Image Processing in Clinical Cardiology (eBook)

The book authors have a unique combination of clinical cardiology and engineering expertise. Jeffrey Goldberger, M.D., Cardiac Electrophysiologist at Northwestern University Feinberg School of Medicine, has had extensive research experience using signal processing to study the heart. Jason Ng, Ph.D., Research Assistant Professor at the Feinberg School of Medicine, has an electrical engineering background and specializes in signal processing in cardiology.

Foreword 5
Preface 7
Acknowledgments 9
Contents 10
Contributors 12
Part I Fundamental Signal and Image Processing Concepts 15
Architecture of the Basic Physiologic Recorder 16
1.1 Chapter Objectives 16
1.2 Transducers 16
1.3 Amplifiers 18
1.4 Filters 18
1.5 Analog-to-Digital Convertors 19
1.6 Microprocessor 19
Summary of Key Terms 19
Reference 20
Analog and Digital Signals 21
2.1 Chapter Objectives 21
2.2 Analog Signals 21
2.3 Digital Signals 22
2.4 Analog-to-Digital Conversion 23
References 27
Summary of Key Terms 27
Signals in the Frequency Domain 28
3.1 Chapter Objectives 28
3.2 What is the Frequency Domain? 28
3.3 Uses of Frequency Domain Plots 30
3.4 Transforming a Time Domain Signal to the Frequency Domain 32
3.5 Frequency Domain of Digital Signals 33
3.6 Summary 37
References 37
Summary of Key Terms 37
Filters 38
4.1 Chapter Objectives 38
4.2 Noise 38
4.3 Filtering to Improve Signal-to-Noise Ratio 39
4.4 Filtering to Prevent Aliasing 43
4.5 Analog Filters 44
4.6 Digital Filters 46
4.7 Phase Distortion 49
4.8 Summary 50
Summary of Key Terms 51
References 52
Techniques for Event and Feature Detection 53
5.1 Chapter Objectives 53
5.2 Purpose and Challenges of Event and Feature Detection 53
5.3 Event Detection by Amplitude 54
5.4 Event Detection by Slope 56
5.5 Event Detection by Template Matching 58
5.6 Waveform Onset and Offset Detection 61
5.7 Offset Estimation by Amplitude 62
5.8 Offset Estimation by Tangent Line Projection 62
5.9 Offset Estimation by Slope 63
5.10 Offset Estimation by Cumulative Area 63
5.11 Summary 65
References 65
Summary of Key Terms 65
Alternative Techniques for Rate Estimation 66
6.1 Chapter Objectives 66
6.2 Autocorrelation 66
6.3 Frequency Domain Estimation of Rate 69
6.4 Noise 69
6.5 Frequency Variability 70
6.6 Phase Change 73
6.7 Waveform Morphology 74
6.8 Summary 77
References 77
Summary of Key Terms 77
Signal Averaging for Noise Reduction 78
7.1 Chapter Objectives 78
7.2 Dart Board Example 78
7.3 Signal Averaging 79
7.4 Limitations of Signal Averaging 81
7.5 Median Waveforms 82
7.6 Summary 86
References 86
Summary of Key Terms 86
Data Compression 87
8.1 Chapter Objectives 87
8.2 General Concepts 87
8.3 Downsampling 88
8.4 Quantization 89
8.5 Variable Length Codes 90
8.6 Differencing 91
8.7 Template Subtraction 92
8.8 Curve Fitting 92
8.9 Data Transformation 93
8.10 Summary 94
Summary of Key Terms 94
References 95
Image Processing 96
9.1 Chapter Objectives 96
9.2 Sampling 97
9.3 Quantization 99
9.4 Image Resizing 99
9.5 Contrast and Brightness 101
9.6 Images in the Frequency Domain 103
9.7 Noise 104
9.8 Filtering 107
9.9 Signal Averaging 111
9.10 Template Matching 112
9.11 Edge Detection 114
9.12 Color Images 116
Reference 117
Summary of Key Terms 117
Part II Cardiology Applications 118
Electrocardiography 119
10.1 Electrical Activity of the Heart: The Action Potential and Its Propagation 119
10.2 How is the ECG Organized? 122
10.3 High-Pass (Low-Frequency) Filtering of the Analog Signal 126
10.4 High-Pass (Low-Frequency) Filtering in Digital Systems 127
10.5 Low Pass (High Frequency) Filtering 128
10.6 Common Mode Rejection 128
10.7 Analog to Digital Conversion 129
10.8 Formation of a Template for ECG Analysis: Signal Averaging 130
10.9 Formation of a Template for ECG Analysis: Identification of Fiducial Points 131
10.10 Computerized Analysis of the ECG 132
10.11 Reliability of Interpretive Algorithms 133
10.12 Potential Artifacts 134
10.13 Data Storage and Compression 135
References 136
Intravascular and Intracardiac Pressure Measurement 138
References 149
Blood Pressure and Pulse Oximetry 150
12.1 Noninvasive Blood Pressure Recordings 150
12.2 Palpation and Auscultation 150
12.3 Oscillometry 151
12.4 Finapres and Portopres 154
12.5 Doppler Ultrasonic Flowmeter 154
12.6 Arterial Tonometry 155
12.7 Ambulatory Blood Pressure Monitoring 155
12.8 Pulse Oximetry 156
12.9 Signal Processing in Pulse Oximetry 159
References 160
Coronary Angiography 162
13.1 Introduction 162
13.2 Limitations of Current X-Ray Angiographic Technology in Diagnostic and Therapeutic Interventions 163
13.3 Three- dimensional Modeling of Patient-Specific Coronary Arterial Tree and Quantitative Analysis based on X- Ray Angiograms 168
13.4 Clinical Application of 3-D Angiography 178
13.5 Summary 183
13.6 Appendix A 184
13.7 Appendix B 186
13.8 Appendix C 186
13.9 Appendix D 187
References 187
Echocardiography 191
14.1 Introduction to Ultrasound Imaging – The Physiologic Signal 191
14.2 Creating and Receiving the Signal – The Transducer 194
14.3 Manipulating and Embellishing the Signal 195
14.4 Displaying the Signal 198
14.5 Doppler Echocardiography 203
14.6 Factors Influencing Signal Quality 206
14.7 Storing of Data 213
14.8 Advanced Applications of Echocardiographic Imaging 214
14.9 Conclusion 220
References 221
Nuclear Cardiology: SPECT and PET 222
15.1 Introduction 222
15.2 Physiologic Signals 222
15.3 Basic Description of the Techniques 226
15.4 Key Signal Processing Techniques Used 232
15.5 Quality Replication of Signal of Interest 240
15.6 Data Storage 249
References 251
Magnetic Resonance Imaging 254
16.1 Basic Description of the Technique(s) 254
16.2 Key Signal Processing Techniques Used 258
16.3 Factors Interfering with Quality Replication of the Signal of Interest 265
16.4 How are Data Stored 274
16.5 Appendix: MRI Image Formation 275
References 276
Computed Tomography 277
17.1 Introduction 277
17.2 Section 1: Technical 277
17.3 Section 2: Coronary Vessels 292
17.4 Section 3: Non- Coronary Cardiac 298
17.5 Conclusion 302
References 302
Summary of Key Terms 302
ECG Telemetry and Long Term Electrocardiography 305
18.1 Types of Recorders 305
18.2 Principles of Telemetry 308
18.3 Playback Systems and Analysis 311
18.4 Artifacts 316
References 318
Intracardiac Electrograms 320
19.1 Characteristics of Unipolar and Bipolar Electrogram Recordings 324
19.2 Frequency Domain Analysis of Atrial Fibrillation 340
References 344
Advanced Signal Processing Applications of the ECG: T- Wave Alternans, Heart Rate Variability, and the Signal Averaged ECG 348
20.1 Introduction 348
20.2 T- Wave Alternans ( TWA) 349
20.3 Heart Rate Variability (HRV) 363
20.4 Signal Averaged ECG (SAECG) 369
20.5 Conclusions 375
References 375
Digital Stethoscopes 380
21.1 Introduction 380
21.2 Development and Principles of Operation 380
21.3 Electronic Stethoscopes 383
References 389
Index 391