Dual Energy CT in Clinical Practice (eBook)

Dual Energy CT in Clinical Practice 3
Copyright Page 4
Foreword 5
Preface 6
Contents 7
Part I Physical Implementation 9
Physical Background 10
1 History 10
2 X-ray Spectra 11
3 Detector Technology 11
4 Tissue Properties 12
5 Dual-Source CT 12
6 Rapid Voltage Switching 13
7 Layer Detector 14
8 Sequential Acquisition 14
9 Radiation Exposure 15
10 Clinical Applications 15
11 Summary 15
References 15
Dual Source CT 17
1 Dual Source Dual Energy Scanning 18
1.1 Introduction 18
1.2 Scanner Design 18
1.2.1 SOMATOM Definition 18
1.2.2 SOMATOM Definition Flash 19
1.3 Data Acquisition 20
2 Image-Based DECT Analysis 22
2.1 Introduction 22
2.2 The Thin Absorber Case 22
2.3 Mixed Image, Monoenergetic Image, Dual Energy Index 23
2.4 Material Decomposition Analysis 24
2.5 Material Labeling and Highlighting 24
3 Outlook 25
References 25
Dual Layer CT 27
1 Introduction 28
2 Physical Background 28
3 System Design 30
4 Image Reconstruction 30
4.1 Image Reconstruction and Energy Map 30
4.2 Material Separation and Noise 31
4.3 Polychromatic Correction 33
5 Post-processing 35
5.1 The Vectorial Separation 35
5.2 The Probability Separation 36
5.3 3D Rendering 36
References 40
Gemstone Detector: Dual Energy Imaging via Fast kVp Switching 41
1 Physical Background 41
2 System Design 42
3 Image Reconstruction 43
4 Projection-Based Material Decomposition 43
5 Post Processing 44
5.1 Noise Suppression 44
5.2 GSI Viewer 44
6 Future Research/Applications 45
References 47
Dual-Energy Algorithms and Postprocessing Techniques 48
1 Introduction 48
2 How to Process 49
2.1 Projection Space Approach 49
2.2 Image Space Approach 50
3 Type of DE Image 51
3.1 Blended Image 51
3.2 Material-Selective Image 52
3.3 Energy-Selective Image 54
4 Determinants of IQ/Dose 54
References 56
Part II Vascular System 57
Head and Neck 58
1 Clinical Background 58
2 Scan Protocol 59
3 Contrast Material Injection 61
4 Postprocessing 61
5 Diagnostic Evaluation 61
5.1 Stroke CT and Stenosis Evaluation 61
5.2 Virtual Unenhanced Images and Brain Hemorrhage 61
5.3 Intracranial Aneurysm, Angiomas, and Fistulas 62
6 Scientific Evidence 63
References 63
Aorta 64
1 Clinical Background 64
2 Physical Background 65
3 Scan Protocol 66
4 Contrast Material Injection 66
5 Postprocessing 67
6 Diagnostic Evaluation 67
7 Scientific Evidence 68
References 68
Peripheral Arteries 70
1 Clinical Background 70
2 Physical Background 71
3 Scan Protocol 71
4 Contrast Material Injection 72
5 Postprocessing 72
6 Diagnostic Evaluation 72
7 Scientific Evidence 72
References 74
Plaque Differentiation 76
1 Introduction 76
2 Rationale of Dual-Energy CT 77
2.1 Original Intensity Space 78
2.2 Dual-Energy CT Imaging of Plaques 78
3 Potential Future Directions for Dual-Energy CT Plaque Imaging 79
4 Conclusion 81
References 81
Part III Thoracic Imaging 83
Lung Perfusion 84
1 Clinical Background 85
2 Physical Background 85
3 Scan Protocol 86
4 Contrast Material Injection 87
5 Postprocessing 87
6 Diagnostic Evaluation 88
7 Scientific Evidence 88
References 91
Lung Ventilation 92
1 Background: Basic Principles 93
2 Patient Preparation 95
3 Scan Protocol 95
4 Technical Requirements for Xenon Application 96
5 Xenon Ventilation CT in Combination with Iodine Mapping in Critically Ill Patients 96
6 Postprocessing 97
7 Diagnostic Evaluation 97
8 Limitations of the Method 98
9 Conclusion 99
References 99
Pulmonary Nodules and Lung Cancer 101
1 Introduction 101
1.1 Clinical Background 101
2 Characterization of Pulmonary Nodules Using Dynamic Contrast-Enhanced CT 102
3 Dual-Energy CT for Characterization of Pulmonary Nodules 103
4 Scientific Evidence 106
5 Conclusion 107
References 108
Myocardial Perfusion 110
1 Introduction 111
2 Clinical Background 112
3 Dual-Energy CT for the Evaluation of Myocardial Perfusion 112
4 Technical Background: Concept of Dual-Source CT and Dual-Energy Imaging 113
4.1 First-Generation Dual-Source CT 113
4.2 Second Generation Dual-Source CT 113
5 Scan Protocols 113
5.1 Single-Phase Contrast-Enhanced Dual-Energy Acquisition with First-Generation Dual-Source CT 113
5.2 Single-Phase Contrast-Enhanced Dual-Energy Acquisition with Second Generation Dual-Source CT 114
5.3 Three-Phase Contrast-Enhanced Dual-Energy Acquisition with First-Generation Dual-Source CT 114
5.4 Three-Phase Contrast-Enhanced Dual-Energy Acquisition with Second Generation Dual-Source CT 115
6 Radiation Dose Considerations 115
7 Postprocessing and Analysis of Myocardial Perfusion 115
8 Clinical Application 117
References 122
Part IV Neuroradiological Imaging 124
Neurological Applications 125
1 Clinical Background 126
2 Physics Background 127
3 Sample Scan Protocols 127
4 Contrast Material Injection 128
5 Postprocessing 128
6 Potential Diagnostic Utility 129
6.1 Intracranial Hemorrhage, Contrast Staining, and Calcification 129
6.2 Carotid Plaque Characterization 130
6.3 CT Angiography and Perfusion with Low Contrast Volumes 130
6.4 Improved Visualization of Anatomic Structures near Osseous or Metallic Surfaces 134
7 Bone Removal for Intracranial CT Angiograms 135
8 Molecular Imaging 135
9 Conclusion 135
References 138
Part V Abdominal Imaging 141
Liver Imaging 142
1 Clinical Background 142
2 Physical Background 143
3 Scan Protocol and Contrast Injection 143
4 Post-processing 146
5 Diagnostic Evaluation and Scientific Evidence 147
6 Conclusion 150
References 151
Kidney Imaging 153
1 Clinical Background 153
2 Technical Background 154
2.1 Technical Considerations 154
2.2 Comparison of True and Virtual Nonenhanced Images in Renal DECT 156
2.3 Characterization of Renal Masses Using Single-Phase DECT 157
3 Discussion 159
References 162
Pancreas 163
1 Clinical Background 163
2 Physical Background 165
3 Scan Protocol 165
4 Contrast Material Injection 166
5 Post-Processing 166
6 Diagnostic Evaluation 167
7 Scientific Evidence 169
References 172
Kidney Stones 173
1 Clinical Background 174
2 Physical Background 174
3 Scan Protocol 175
4 Postprocessing 176
5 Diagnostic Evaluation 178
6 Scientific Evidence 179
References 184
Part VI Extremities 186
Tendons and Ligaments 187
1 Introduction 187
2 Tendons and ligaments 188
2.1 Tendons 188
2.2 Ligaments 189
2.2.1 Knee 189
2.2.2 Shoulder 190
References 191
Gout 192
1 Clinical Background 193
2 Physical Background 196
3 Scan Protocol 196
3.1 Gout Protocol: Upper Extremity (Wrists) Siemens Definition Dual Source Scanner 196
3.1.1 Patient Position 196
3.1.2 Scan Range 196
3.2 Gout Protocol: Lower Extremity (Ankles) Siemens Definition Dual Source Scanner 196
3.2.1 Patient Position 196
3.2.2 Scan Range 196
3.3 Technical Factors 196
4 Post-Processing 197
5 Diagnostic Evaluation 197
5.1 Case 1 198
5.2 Case 2 199
5.3 Case 3 203
6 Scientific Evidence 203
References 205
Index 207