Digital Mammography (eBook)

Foreword 5
Preface 6
Contents 7
Abbreviations 9
Chapter 1 12
Basic Physics of Digital Mammography 12
1.1 Introduction 12
1.2 Characterizing Imaging Performance 13
1.3 Basic Physics of Image Acquisition 13
1.3.1 Detection of X-Rays 14
1.3.2 Recording of the Image 15
1.3.3 Sampling 16
1.3.3.1 Some Spatial Sampling Concepts 16
1.3.3.2 Sampling of Signal Level 17
1.4 Noise 17
1.4.1 Quantum Noise 17
1.4.2 Structural Noise 18
1.4.3 Signal Difference-to-Noise Ratio 18
1.5 Radiation Dose 18
1.6 Scattered Radiation 18
1.7 Spatial Resolution 19
1.7.1 Modulation Transfer Function 19
1.8 Detective Quantum Effi ciency 20
1.9 Energy Spectra for Digital Mammography 21
1.10 Clinical Dose Levels in Digital Mammography 22
References 22
Chapter 2 23
Detectors for Digital Mammography 23
2.1 Introduction 23
2.2 Geometric Considerations 24
2.3 Basic Physics of X-Ray Detectors 24
2.3.1 Photoconductors 25
2.3.2 Phosphors 26
2.3.3 Photostimulable Phosphors 26
2.3.4 Noble Gases 26
2.4 Aspects of Detector Performance 26
2.4.1 Quantum Detection Effi ciency 26
2.4.2 Sensitivity 27
2.4.3 Noise in Detectors 28
2.5 Detector Corrections 29
2.5.1 Uniformity Correction 29
2.5.2 Resolution Restoration 31
2.6 Linear vs. Logarithmic Response 31
2.7 Detector Types 31
2.7.1 Phosphor-Flat Panel 31
2.7.2 Phosphor-CCD System 33
2.7.3 Photostimulable Phosphor System 33
2.7.4 Selenium Flat Panel 36
2.7.5 X-Ray Quantum Counting Systems 37
2.8 Spatial Resolution 37
2.9 Toward Smaller Dels 40
2.10 Automatic Exposure Control 40
References 41
Chapter 3 42
Quality Control in Digital Mammography 42
3.1 Introduction 42
3.2 Image Quality 44
3.3 Image Noise 45
3.4 Homogeneity and Artifacts 46
3.4.1 Artifacts Due to Problems with the Image Receptor 47
3.4.2 Artifacts Related to Detector Calibration 47
3.4.3 Artifacts Due to Other Problems 48
3.5 Dosimetry 48
3.6 Quality Control of Image Processing 50
3.6.1 Radiological Evaluation 51
3.6.2 Quality of Image Processing Algorithms in Terms of Detectability of Lesions 52
3.7 Quality Control of Monitors 53
3.7.1 Physics Tests 54
3.7.2 Human Reading of Test Patterns 55
3.7.3 Fully Automated Procedures 55
3.7.4 Conclusion 57
3.8 Routine Quality Control Tests and Their Automation 57
3.8.1 A Practical Example of Periodic Technical Quality Control 58
3.8.2 Conclusion 58
References 63
Chapter 4 64
Classification of Artifacts in Clinical Digital Mammography 64
4.1 Introduction 64
4.2 Classifi cation 65
4.2.1 Technologist-Related Artifacts 65
4.2.2 Mammography Unit Related Artifacts 67
4.2.3 Software-Related Artifacts 71
4.3 Conclusion 74
References 75
Chapter 5 77
Image Processing 77
5.1 Introduction 77
5.2 Grayscale Transforms 78
5.3 Spatial Enhancement 80
5.3.1 Unsharp Masking 80
5.3.2 Adaptive Histogram Equalization 81
5.3.3 Multiscale Image Enhancement 82
5.3.4 Peripheral Enhancement 83
5.4 Matching Current and Prior Mammograms 85
5.5 Physics-Based Methods 88
5.6 Evaluation of Mammogram Processing 89
References 90
Chapter 6 92
Computer-aided Detection and Diagnosis 92
6.1 Introduction 92
6.2 Short Historical Overview 93
6.3 Clinical Need for CAD in Mammography 94
6.3.1 Missed Cancers 94
6.3.2 Low Positive Predictive Value for Biopsy Recommendations 95
6.3.3 Reader Variability 95
6.4 Generic Description of CADe and CADx Schemes 95
6.4.1 Methodology 95
6.4.2 Required Pixel Size 98
6.4.3 Full-Field Digital Mammography 100
6.5 Evaluation Methods for CADe and CADx 100
6.5.1 Evaluation of CADe Schemes 100
6.5.2 Evaluation of CADx Schemes 101
6.6 Observer Studies for CADe and CADx 102
6.7 Clinical Studies for CADe 103
6.7 1 Methodology 103
6.7.2 Recall Rate 105
6.7.3 Comparison with Double Reading 105
6.8 Current Research in CADe and CADx 106
6.8.1 Improving CADe Scheme Performance 106
6.8.1.1 Temporal Comparison (Comparison with Prior) 106
6.8.1.2 Spatial Comparison (Different Views) 106
6.8.2 CADe as Pre-screen 107
6.8.3 Concurrent Reading with CADe 107
6.8.4 Interactive CADe 108
6.8.5 CADx Multimodality 108
6.8.6 CADe and CADx for Tomosynthesis and Breast CT 108
6.9 Financial Disclosure 109
References 109
Chapter 7 114
Softcopy Reading 114
7.1 Introduction 114
7.2 Softcopy Image Quality 115
7.2.1 Display Optimization 115
7.3 Softcopy “Hanging Strategies” 116
7.3.1 Typical Hanging Options 116
7.4 Viewing Strategies and Perception 117
7.4.1 Vision Basics 117
7.4.2 Visual Search 118
7.4.3 Interpretation Errors 119
7.4.4 What Attracts Attention? 120
7.4.5 Reader Variability and Expertise 121
7.5 Reading Environment 122
7.5.1 Reader Fatigue 122
7.6 Conclusions 124
References 124
Chapter 8 127
Digital Workflow, PACS, and Telemammography 127
8.1 Introduction 128
8.2 Workfl ow in Digital Mammography 129
8.2.1 Technology 129
8.2.1.1 Image Generating Equipment 129
8.2.1.2 Display Systems 129
8.2.1.3 Diagnostic Workstations and User Interfaces 130
8.2.1.4 Setups for Clinical Review 130
8.2.2 Impact on the Work of the Radiographers 131
8.2.2.1 Working Effi ciency 131
8.2.2.2 Increased Complexity 131
8.2.2.3 Stricter Procedures 132
8.2.2.4 Pitfalls 132
8.2.2.5 Improved Functionalities 132
8.2.3 Impact on the Work of the Radiologist 132
8.2.3.1 Image Viewing 132
8.2.3.2 Organization of Image Reading 133
8.2.3.3 The Global Reporting Workfl ow 134
8.2.4 Impact on the Referring Physicians 134
8.2.4.1 Image Viewing 134
8.2.4.2 Integrating Image Viewing into the Electronic Medical Record 134
8.2.4.3 Integrating Images into Hospital-Wide Processes 135
8.3 PACS and Integrating Images into Overall Informatics 135
8.3.1 Motivation 135
8.3.2 Integrating the Components that Support the Image Workfl ow 136
8.3.2.1 Integrating the PACS with the HIS 136
8.3.2.2 Integrating the Imaging Modality with the HIS 136
8.3.2.3 Integrating the Diagnostic Viewing Workstation with the RIS 137
8.3.2.4 Integrating Clinical Image Viewing Within the EMR 137
8.3.2.5 DICOM 137
8.3.2.6 IHE 139
8.3.3 Strategic Decisions on Integrating Technology Infrastructure 139
8.3.3.1 Storage Consolidation 140
8.3.3.2 Thinking of Technology as an Infrastructure 140
8.3.4 Central PACS vs. Departmental or Dedicated Systems 140
8.3.4.1 Reporting 141
8.3.4.2 Image-Management Islands 141
8.3.4.3 Embedding into Hospital-Wide Operations 141
8.3.5 Organizational Limits to Informatics Integration 142
8.4 Telemammography 142
8.4.1 Situation 142
8.4.1.1 Driving Forces 142
8.4.1.2 Geographical vs. Organizational Distance 143
8.4.1.3 Connections at Many Levels 143
8.4.2 Selected Technology Aspects for Telemammography 144
8.4.2.1 The Internet as a Source of Bandwidth 144
8.4.2.2 Security 144
8.4.2.3 Image Compression 145
8.4.3 Organizing Image Exchange and the IHE XDS Initiative 145
8.4.3.1 Image Batch Transmission vs. Remote On Line Access 145
8.4.3.2 Pushing Images to the Partner 146
8.4.3.3 Pulling Images from any Partner: The IHE XDS Initiative 146
8.4.4 Integrating Images into a Teleworkflow 147
8.4.4.1 Centralizing Organization of Screening Using Telecommunication 147
8.4.4.2 Organizational Challenges in a Decentralized Screening Organization 147
8.4.5 Choosing Between Integration into Central or Local Workfl ow 148
References 143 149
Chapter 9 150
Digital Mammography Clinical Trials: The North American Experience 150
9.1 Introduction 150
9.2 The Colorado–Massachusetts Screening Trial 151
9.2.1 Results 151
9.3 ACRIN: DMIST 153
9.3.1 Protocol and Data Collection 155
9.3.2 Results 155
9.4 Conclusion 159
References 159
Chapter 10 160
Digital Mammography in European Population-Based Screening Programs 160
10.1 Introduction 161
10.2 European Studies Comparing Screen-Film and Digital Mammography in Breast Cancer Screening 161
10.2.1 The Oslo I Study 162
10.2.2 The Oslo II Study 165
10.2.3 The Helsingborg Study 165
10.2.4 The Florence Study 167
10.2.5 The Vestfold County Study 167
10.2.6 The Tromsø Study 168
10.2.7 The Central East London Breast Screening Service (CELBSS) Study 168
10.2.8 The Barcelona Study 169
10.2.9 The Digital Screening Project Preventicon (DSPP) Study 169
10.2.10 The Irish National Breast Screening Program (INBSP) Study 170
10.2.11 The Sogn and Fjordane Study 170
10.3 Overall Results and Discussion on the European Studies 171
10.4 Conclusions from the European Studies 175
References 176
Chapter 11 179
Mammographic Signs of Malignancy: Impact of Digital Mammography on Visibility and Appearance 179
11.1 Introduction 179
11.2 Mass Lesions 180
11.2.1 Determining the Presence of a True Mass Lesion 180
11.2.2 Distinguishing Benign and Malignant Mass Lesions 180
11.3 Calcifications 181
11.3.1 Detection of Subtle Microcalcifications 184
11.3.2 Classification of Benign and Malignant Breast Calcifications 185
11.4 Other Mammographic Signs of Malignancy 186
11.4.1 Architectural Distortions 186
11.4.2 Asymmetries 188
11.4.3 Associated Findings 188
References 190
Chapter 12 191
Contrast-Enhanced Digital Mammography 191
12.1 Introduction 192
12.2 Basic Concepts of the Technique 192
12.2.1 Dual-Energy Technique 192
12.2.2 Temporal Subtraction Technique 193
12.3 Image Analysis and Interpretation 193
12.4 Comparison of Dual-Energy vs. Temporal Technique 196
12.5 Advantages and Disadvantages of CEDM 197
12.6 First Clinical Experience 197
12.7 Potential Clinical Applications 198
12.8 Future Improvements 198
12.9 Conclusion 201
References 201
Chapter 13 203
Digital Breast Tomosynthesis and Breast CT 203
13.1 Introduction 203
13.2 Hardware 204
13.3 Software: Image Viewing Systems and Reconstruction Algorithms 206
13.4 Clinical Applications 208
13.5 Dose 210
13.6 Contrast Media 211
13.7 DBT and Computer-Aided Diagnosis 212
13.8 DBT or CT? 212
References 212
Subject Index 214
Contributors 218