Tai, Chi Kin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (p. 56-59). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.7 / Chapter 2 --- Theoretical Background --- p.9 / Chapter 2.1 --- Nuclear Magnetic Resonance --- p.9 / Chapter 2.1.1 --- Nuclear spin and macroscopic magnetization --- p.10 / Chapter 2.1.2 --- Precession and Larmor Frequency --- p.12 / Chapter 2.1.3 --- Radio-frequency excitation --- p.13 / Chapter 2.1.4 --- Radio-frequency relaxation --- p.15 / Chapter 2.1.5 --- Spin echoes --- p.17 / Chapter 2.1.6 --- Contrast mechanisms --- p.17 / Chapter 2.2 --- Magnetic Resonance Imaging --- p.20 / Chapter 2.2.1 --- MRI machine hardware --- p.20 / Chapter 2.2.2 --- Slice selection --- p.22 / Chapter 2.2.3 --- Frequency encoding --- p.23 / Chapter 2.2.4 --- Phase encoding --- p.26 / Chapter 2.2.5 --- Pulse sequences --- p.26 / Chapter 2.2.6 --- Field of view and resolution --- p.28 / Chapter 3 --- Parallel Magnetic Resonance Imaging --- p.30 / Chapter 3.1 --- Motivation --- p.30 / Chapter 3.1.1 --- Aliasing --- p.31 / Chapter 3.2 --- Coil array and coil sensitivities --- p.32 / Chapter 3.3 --- Sensitivity encoding --- p.32 / Chapter 3.3.1 --- Estimation of coil sensitivities --- p.33 / Chapter 3.3.2 --- SENSE reconstruction --- p.33 / Chapter 3.4 --- pMRI reconstruction by TV regularization --- p.35 / Chapter 3.4.1 --- Model for coil images --- p.35 / Chapter 3.4.2 --- Total variation-regularization approach --- p.36 / Chapter 4 --- Reconstruction Results --- p.39 / Chapter 4.1 --- Simulation --- p.39 / Chapter 4.1.1 --- Reconstruction quality --- p.41 / Chapter 4.1.2 --- Reconstruction results --- p.43 / Chapter 4.2 --- MRI phantom experiments --- p.44 / Chapter 4.2.1 --- Reconstruction quality --- p.48 / Chapter 4.2.2 --- Reconstruction results --- p.49 / Chapter 4.3 --- In-vivo MRI images --- p.51 / Chapter 5 --- Discussions and Conclusions --- p.54 / Bibliography --- p.56

This thesis addresses the problem of producing three-dimensional constrained Delaunay triangulated meshes from the sequential two dimensional MRI medical image slices. The approach is to generate the volumetric meshes of the scanned organs as a result of a several low-level tasks: image segmentation, connected component extraction, isosurfacing, image smoothing, mesh decimation and constrained Delaunay tetrahedralization. The proposed methodology produces a portable application that can be easily adapted and extended by researchers to tackle this problem. The application requires very minimal user intervention and can be used either independently or as a pre-processor to an adaptive mesh refinement system. / Finite element analysis of the MRI medical data depends heavily on the quality of the mesh representation of the scanned organs. This thesis presents experimental test results that illustrate how the different operations done during the process can affect the quality of the final mesh.

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