Image-Based Computational Modeling of the Human Circulatory and Pulmonary Systems (eBook)

Foreword 6
Preface 8
Contents 13
Contributors 15
Part I Cardiac and Pulmonary Imaging, Image Processing, and Three-Dimensional Reconstruction in Cardiovascular and Pulmonary Systems 19
1 Image Acquisition for Cardiovascular and Pulmonary Applications 20
1.1 Introduction to Imaging 20
1.1.1 Invasive Techniques 22
1.1.2 Role of Noninvasive Imaging 22
1.2 Ultrasound/Echocardiography 23
1.2.1 Principles of Ultrasound 23
1.2.1.1 M-Mode 25
1.2.1.2 2D Ultrasound 26
1.2.2 Echocardiography 27
1.2.2.1 Morphologic Imaging 27
1.2.2.2 Function 28
1.2.2.3 Flow (Doppler) 28
1.2.2.4 TTE Versus TEE 29
1.2.3 Vascular/Peripheral 30
1.3 Computed Tomography (CT) 31
1.3.1 Principles of CT 31
1.3.1.1 Basic CT 32
1.3.1.2 Multidetector CT 33
1.3.2 Cardiac CT 34
1.3.2.1 Coronary Arteries 34
1.3.2.2 Aorta 35
1.3.2.3 Cardiac Function 35
1.3.3 Pulmonary CT 36
1.3.3.1 Parenchyma 36
1.3.3.2 Pulmonary Angiography 37
1.4 Magnetic Resonance Imaging (MRI) 37
1.4.1 Principles of MRI 37
1.4.1.1 Signal Generation 38
1.4.1.2 General Techniques and Contrast Mechanisms 38
1.4.1.3 Morphology 39
1.4.1.4 Function 40
1.4.1.5 Perfusion/Ischemia 42
1.4.2 MR Angiography 43
1.4.3 Pulmonary MRI: Emerging Techniques 45
1.5 Other Techniques 47
1.5.1 SPECT 47
1.5.2 PET 48
1.6 Summary 49
References 49
2 Three-dimensional and Four-dimensional Cardiopulmonary Image Analysis 51
2.1 Introduction 51
2.2 Segmentation and Modeling Methodology 52
2.2.1 Active Shape and Appearance Models 52
2.2.1.1 Building a 3D Statistical Shape Model 53
2.2.1.2 Extension to Higher Dimensions 54
2.2.1.3 Combining Shape and Appearance 54
2.2.1.4 Robust ASM and AAM Implementations 55
2.2.2 Region Growing and Fuzzy Connectivity Segmentation 56
2.2.2.1 Region Growing 56
2.2.2.2 Fuzzy Connectivity-Based Segmentation 57
2.2.3 Graph-Based Segmentation 58
2.2.3.1 Approaches Based on Rectangular Graph Structures 58
2.2.3.2 Minimum-Cut Approaches 61
2.2.3.3 Cost Functions 62
2.3 Cardiac Applications 63
2.3.1 Modeling and Quantitative Analysis of the Ventricles 64
2.3.1.1 Manual Ventricle Segmentation 64
2.3.1.2 3D Shape Generation 66
2.3.2 Tetralogy of Fallot Classification 68
2.3.2.1 Study Population and Experimental Methods 69
2.3.2.2 Novel Ventricular Function Indices 70
2.4 Vascular Applications 71
2.4.1 Connective Tissue Disorder in the Aorta 71
2.4.1.1 4D Segmentation of Aortic MR Image Data 72
2.4.1.2 Disease Detection 74
2.4.1.3 Accuracy of Segmentation and Classification 75
2.4.2 Aortic Thrombus and Aneurysm Analysis 76
2.4.2.1 Initial Luminal Surface Segmentation 78
2.4.2.2 Graph Search and Cost Function Design 79
2.4.2.3 Data and Results 80
2.4.3 Plaque Distribution in Coronary Arteries 83
2.4.3.1 Segmentation and 3D Fusion 84
2.4.3.2 Hemodynamic and Morphologic Analysis 88
2.4.3.3 Studies and Results 89
2.5 Pulmonary Applications 91
2.5.1 Segmentation and Quantitative Analysis of Airway Trees 92
2.5.1.1 Airway Tree Segmentation 93
2.5.1.2 Quantitative Analysis of Airway Tree Morphology 95
2.5.2 Quantitative Analysis of Pulmonary Vascular Trees 98
2.5.3 Segmentation of Lung Lobes 104
2.6 Discussions and Conclusions 107
References 108
Part II Computational Techniques for Fluid and Soft Tissue Mechanics, FluidStructure Interaction, and Development of Multi-scale Simulations 119
3 Computational Techniques for Biological Fluids: From Blood Vessel Scale to Blood Cells 120
3.1 Introduction 120
3.2 Computational Methods for Macro-scale Hemodynamics 121
3.2.1 Governing Equations 121
3.2.1.1 The Fluid Flow Equations 121
3.2.1.2 The Structural Equations 123
3.2.1.3 Boundary Conditions at the Fluid--Structure Interface 126
3.2.2 Numerical Methods for Flows with Moving Boundaries 126
3.2.2.1 Boundary-Conforming Methods 127
3.2.2.2 Non-boundary-Conforming Methods 129
3.2.2.3 Hybrid Methods: Body-Fitted/Immersed Boundary Methods 133
3.2.3 Fluid--Structure Interaction Algorithms 133
3.2.3.1 Loose and Strong Coupling Strategies 134
3.2.3.2 Stability and Robustness Issues 135
3.2.4 Efficient Solvers for Physiologic Pulsatile Simulations 136
3.2.5 High-Resolution Simulations of Cardiovascular Flow 137
3.2.5.1 Fluid--Structure Interaction Simulations of Mechanical Bileaflet Heart Valves 137
3.2.5.2 Numerical Simulations of Trileaflet Heart Valve Hemodynamics 139
3.3 Computational Methods for Blood Cell Scale Simulations 142
3.3.1 Background 142
3.3.2 Review of Numerical Methods for Blood Cell-Resolving Simulations 142
3.3.2.1 Boundary-Integral Methods for Cell-Level Simulation 143
3.3.2.2 Immersed Boundary Method 144
3.3.2.3 Particle Methods 144
3.3.2.4 Lattice Boltzmann 145
3.3.3 Lattice-Boltzmann Methodology 145
3.3.3.1 Lattice-Boltzmann BGK (LBGK) Model for Fluid Flow 145
3.3.3.2 Transient Finite-Element FSI Model 146
3.3.4 Membrane Models 151
3.3.4.1 Comparison of Red Blood Cell Models 154
3.3.5 Rheology, Stress, and Microstructure of Blood 154
3.3.5.1 Bulk Rheology 155
3.3.5.2 Shear-Thinning Behavior 156
3.3.5.3 Microstructure 158
3.3.5.4 Local Stress Environment in Blood 161
3.4 Future Directions 162
References 163
4 Formulation and Computational Implementation of Constitutive Models for Cardiovascular Soft Tissue Simulations 171
4.1 Introduction 171
4.2 Constitutive Models for Cardiovascular Soft Tissues 173
4.2.1 Condition Number of D 176
4.3 Structural Constitutive Models 177
4.4 Finite-Element Implementation 181
4.4.1 Fung Model Implementation Example 184
4.4.2 Biaxial Testing Simulations 184
4.4.3 Prosthetic Valve Simulations 187
4.4.4 Engineered Heart Valve Leaflet Tissue Simulations 189
4.5 Finite-Element Models of Heart Valve Leaflets 193
4.5.1 Degenerate Solid Shell 194
4.5.2 Element Pathology 195
4.5.3 Stress-Resultant Shell 196
4.5.4 Continuum Shell 198
4.6 Summary 198
4.7 Appendix: Shell Kinematics 199
References 201
5 Algorithms for Fluid Structure Interaction 205
5.1 Introduction 205
5.1.1 Key Aspects of Fluid--Structure Interaction Problems 206
5.2 Governing Equations and Important Parameters 207
5.3 Spatial Discretization to Couple Fluid and Solid Dynamics 209
5.4 ALE-Type Methods 210
5.5 Immersed Boundary Method 210
5.6 Immersed Interface Method 212
5.7 Sharp Interface Method 213
5.8 Finite Element Methods 216
5.9 Fictitious Domain Method 216
5.10 Immersed Finite Element Methods 216
5.11 Issues Related to the Temporal Update of the Coupled FluidSolid System 217
5.12 Numerical Stiffness 217
5.13 Material Density and Slenderness 220
5.14 Rapidity of Motion and Deformation 221
5.15 Techniques for Coupling of the Temporal Update of the Fluid and Solid Subsystems 221
5.16 Weak and Strong Coupling Algorithms 222
5.17 Three Different Approaches to FSI Modeling in Biomedical Applications 224
5.17.1 FSI Approach 1 224
5.17.1.1 Results 227
5.17.2 FSI Approach 2 228
5.17.2.1 Results 230
5.17.3 FSI Approach 3 232
5.18 Modeling of Mechanical Heart Valves 235
5.19 Leaflet Rebound 236
5.19.1 Results 237
5.20 Effect of Flow During Closure and Rebound Phases 237
5.21 Modeling of Tissue Heart Valves 239
5.21.1 Challenges in Modeling Tissue Heart Valves 239
5.21.1.1 Results of Simulations 240
5.22 Concluding Remarks 244
References 244
6 Mesoscale Analysis of Blood Flow 249
6.1 Introduction 249
6.2 Scaling Estimates 252
6.3 Modeling Adhesion Force Between Blood Cells 254
6.4 Microscale Modeling: Deformable Blood Cells 260
6.5 Mesoscale Modeling Using the Discrete Element Method 263
6.6 Mesoscale Modeling Using Dissipative Particle Dynamics 269
6.7 Bridging the Scales 274
References 275
Part III Applications of Computational Simulations in the Cardiovascular and Pulmonary Systems 281
7 Arterial Circulation and Disease Processes 282
7.1 Introduction 282
7.2 Artery Wall Structure 284
7.3 Endothelium 285
7.4 Mechanical Forces on the Arterial Wall 286
7.5 Wall Shear Stress 287
7.6 Mechanisms of Disease Formation 287
7.7 Flow in Small Vessels Hemodynamic Modelling of Coronary Flows 288
7.8 The Influence of Wall Motion 289
7.9 Boundary Conditions for Coronary Flows 289
7.10 Velocity 290
7.11 Outlet Boundary Conditions for Coronary Flows 291
7.12 Numerical Model Development 291
7.13 Coronary Flow Analysis 292
7.14 Steady Flow in the Right Coronary Artery 292
7.15 Pulsatile Flow in the Right Coronary Artery 294
7.16 Steady Flow in the Left Coronary Artery 294
7.17 Pulsatile Flow in the Left Coronary Artery 297
7.18 Discussion 299
7.19 Flow in Large Vessels Hemodynamic Modeling of Aortic Flows 300
7.20 Boundary Conditions 301
7.21 Steady-Flow Boundary Conditions 302
7.22 Steady Flow Realistic Model 303
7.23 Influence of Steady Input Boundary Conditions 306
7.24 Pulsatile Flow in a Bifurcation 307
7.25 Geometrical Effects 307
7.26 Geometrical Differences Associated with the Realistic and Idealized AAA Models 310
7.27 Treatment of Arterial Disease 312
7.27.1 Vascular Aneurysm Grafting 313
7.27.2 Vascular Bypass Grafting 314
7.28 Future Trends in Vascular and Cardiovascular Disease Modeling 318
References 319
8 Biomechanical Modeling of Aneurysms 325
8.1 Introduction 325
8.1.1 Incidence and Epidemiology 325
8.1.2 Role for Biomechanical Modeling and Simulation 326
8.2 Geometric Modeling of Aneurysms 327
8.2.1 Abdominal Aortic Aneurysms 328
8.2.2 Cerebral Aneurysms 330
8.2.3 Summary 333
8.3 Material Modeling of Aneurysms 333
8.3.1 Abdominal Aortic Aneurysms 334
8.3.2 Cerebral Aneurysms 335
8.4 Computational Simulations of Intra-aneurysmal Hemodynamics 336
8.4.1 Abdominal Aortic Aneurysm 336
8.4.2 Cerebral Aneurysms 337
8.4.3 Challenges in Aneurismal Hemodynamic Simulations 339
8.5 Computational Estimations of Aneurysmal Wall Stress and Strain 339
8.5.1 Abdominal Aortic Aneurysm 340
8.5.2 Cerebral Aneurysms 343
8.6 FluidStructure Interaction Studies 344
8.7 Framework for Biomechanical Modeling of Growth and Remodeling 345
8.8 Future Directions 348
References 349
9 Advances in Computational Simulations for Interventional Treatments and Surgical Planning 354
9.1 Introduction 354
9.2 Analysis for Endovascular Treatment and Device Design 356
9.2.1 Introduction 356
9.2.2 Identification of Vulnerable Plaque 356
9.2.3 Endovascular Balloon Angioplasty 357
9.2.4 Endovascular Stents 357
9.3 Patient-Specific Surgical Planning 360
9.3.1 Single-Ventricle Heart Defects: Review of the Clinical Problem 361
9.3.2 Comparing Global Outcome and Cardiovascular Function 363
9.3.3 Comparing Performances of Different Design Variations 364
9.3.3.1 Patient Data Acquisition 364
9.3.3.2 Anatomy Reconstruction and Surrounding Organs Representation 366
9.3.3.3 Modeling the Intervention 367
9.3.3.4 Fast Performance Estimation and Optimization Using 1D FEA Modeling 369
9.3.3.5 Full Postoperative Hemodynamics Characterization and Optimization Using 3D CFD 370
9.3.3.6 Automated Optimization Methods Using 3D CFD 372
9.4 Including Surrounding Organs 373
9.4.1 Geometric Constraints of the Modified Configuration 373
9.4.2 Adapting the Boundary Conditions to the Modified Configuration 374
9.4.2.1 Inlet and Outlet Boundary Conditions 374
9.4.2.2 Material Properties 376
9.5 Future Direction for Biomedical Simulations 376
References 379
10 Computational Analyses of Airway Flow and Lung Tissue Dynamics 385
10.1 Introduction 385
10.2 Basic Anatomy and Physiology 386
10.3 Respiratory Mechanics 387
10.4 Mechanical Input Impedance 391
10.4.1 Inverse Modeling of Respiratory Mechanics 392
10.5 Forward Morphometric Models of the Respiratory System 394
10.5.1 Computational Modeling Example: Airway Thermodynamics in Symmetric and Anatomical Models 398
10.6 Application of Morphometric Models to Computational Studies of Lung Mechanics 399
10.7 Imaging Methodology 400
10.8 Image-Based Computational Models 401
10.8.1 Insights into Bronchoconstriction: Airways and Interdependence 401
10.8.2 Regional Tissue Mechanics 404
10.9 Conclusions 406
References 406
11 Native Human and Bioprosthetic Heart Valve Dynamics 413
11.1 Human Heart Valves 413
11.2 Aortic Valve 415
11.3 Mitral Valve 417
11.4 Diseases of the Heart Valves 419
11.5 Biological Valve Prostheses 419
11.6 Experimental Studies on Valve Dynamics 421
11.7 Three-Dimensional Geometrical Reconstruction of the Aortic and Mitral Valves 424
11.7.1 3D Echocardiography 425
11.7.2 3D Computed Tomography 427
11.7.3 3D Magnetic Resonance Imaging 428
11.8 Computational Simulations of the Native Valves 428
11.8.1 Aortic Valve 428
11.8.2 Mitral Valve 429
11.9 Biological Valve Prostheses 431
11.9.1 Quasi-Static and Dynamic FE Analyses 432
11.9.2 Fluid--Structure Interaction Analysis 434
11.10 Need for Multiscale Simulations 437
11.11 Summary 437
References 438
12 Mechanical Valve Fluid Dynamics and Thrombus Initiation 446
12.1 Background 447
12.1.1 Heart Valve Disease 447
12.1.2 Artificial Heart Valves 447
12.1.2.1 Mechanical Heart Valves 448
12.1.2.2 Bioprosthetic Heart Valves 449
12.1.3 Design and Performance Issues 449
12.1.4 Computational Fluid Dynamics 451
12.1.5 Experimental Fluid Dynamics 452
12.2 FluidStructure Interaction 454
12.2.1 The Need for Fluid--Structure Interaction 454
12.2.1.1 Monolithic vs. Partitioned Methods and Loose vs. Strong Coupling 455
12.2.1.2 Moving Grid Methods 456
12.2.1.3 Fixed Grid Methods 458
12.3 Modeling Damage to Blood Cells 460
12.3.1 Thrombus Formation and Hemolysis 460
12.3.2 Modeling Blood Damage 461
12.3.3 Implementation of Blood Damage Models in CFD 463
12.4 Concluding Remarks 465
References 467
Subject Index 472