Harmonic B_z Algorithms in Magnetic Resonance Electrical Impedance Tomography (MREIT) and Related Studies = MREIT에서의 조화 $B_z$ 알고리듬 및 관련연구

Magnetic resonance electrical impedance tomography (MREIT) is a conductivity imaging modality providing high-spatial resolution. When we inject current through electrodes to a target object, the magnetic flux density is generated by the internal current density. Using MR-machine, we can measure one-component of magnetic flux density, whose direction is parallel to the main magnetic field of the MR-machine. Harmonic $\It{B_z}$ algorithm is a reconstruction algorithm to provide cross-sectional conductivity imaging in MREIT, which uses only one component of magnetic flux density. However, due to the sensitivity of the algorithm, the result is collapsed near regions with low conductivity or insulated regions. In order to reconstruct the conductivity in the such problematic regions, the local harmonic $\It{B_z}$ algorithm was proposed by Seo $\It{et al}$. It requires a special type of triangulation and it still has a trouble to reconstruct conductivity in valley type regions. In this thesis, we propose an algorithm to handle the problematic regions without considering a special type of triangulation, which is based on the discontinuous Galerkin approach. In addition, we suggest a strategy to reconstruct the conductivity in valley type regions under the appropriate assumption. Conductivity image reconstruction in MREIT requires various steps of carefully implemented numerical computations. To facilitate MREIT research, there has been a pressing need for an MREIT software package with efficient user interface. In this thesis, we present an example of such a software, so called CoReHA which stands for conductivity reconstructor using harmonic algorithms. It offers various computational tools including preprocessing of MREIT data, identification of boundary geometry, electrode modeling, meshing and implementation of a finite element method. The conductivity image reconstruction method based on the harmonic $\It{B_z}$ algorithm produces cross-sectional conductivity ima...
Lee, Chang-Ockresearcher이창옥researcher
Issue Date
418667/325007  / 020045883

학위논문(박사) - 한국과학기술원 : 수리과학과, 2010.2, [ ix, 77 p. ]


Harmonic and Local Harmonic B_z algorithm; MREIT; discontinuous Galerkin method; 수학적 관찰; CoReHA; Mathematical Observation; MRI를 이용한 전도율 복구 방법론; 조화 B_z 및 국소적 조화 B_z 알고리듬; 불연속 Galerkin 방법; 전도율 복구 소프트웨어

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