大腦相關疾病通常伴隨病理上的變化，這些變化可透過磁振造影呈現。目前臨床檢驗方式為觀察magnitude與phase影像上數值變化，但先前研究顯示這些影像會隨著病人大腦掃描位置與主磁場角度不同而產生差異，進而影響臨床影像判讀。近幾年，Quantitative Susceptibility Mapping (QSM) 的方法被提出，藉由dipole model deconvolution，上述的主磁場角度影響可被降低，並且能對組織磁化率絕對定量，對於病程的進展有一定貢獻，因此此一方法逐漸被重視。然而QSM計算流程牽涉到許多步驟，其準確性即及可重複性仍需被探討。本研究透過數值模擬設計與仿體實驗驗證QSM準確性，並在 3 Tesla 磁場下探討正常受試者QSM的可重複性。實驗結果顯示著QSM能準確定量組織磁化率,並對於大腦疾病之病程發展研究發展深具潛力。

Routine diagnosis of brain diseases using MRI mostly bases on magnitude and phase images. However, it has been known that image changes with the orientation of patient in the magnet and may become a confounding factor in clinical diagnosis. Through dipole model deconvolution, Quantitative Susceptibility Mapping (QSM) reduces the orientation dependence and achieves tissue susceptibility quantification. QSM potentially serves as a biomarker of disease. However, because QSM involves in many steps, the aim of this study was to investigate the accuracy and reproducibility of QSM. Numerical phantom simulation and phantom experiment were performed for accuracy study. In addition, QSM reproducibility was investigated with human subject study at 3 Tesla. Our results indicate that QSM is capable of accurate susceptibility quantification, which is of high potential for assessing neuronal diseases.

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