磁化率權重影像可以凸顯出不同組織磁化率的差異，對於順磁性物質的累積
比如微出血十分敏感，所產生的信號在影像上會接近呈現黑色，產生有別於傳統
T1、T2 影像的對比。本研究針對具有環狀顯影特徵的病灶，提出一個較客觀的方
法來判斷病灶內的磁化率信號(ILSS)。影像處理共分成三個步驟，分別是圈選ROI、影像分割、找出ILSS。首先利用顯影的特徵來圈選病灶ROI，量測病灶內及正常白質的SWI 訊號後，透過本研究提出的ND(normalized difference)找出病灶中灰階異常低的ILSS 並針對病灶體積、ILSS 體積及其佔病灶之比例進行量測。

本研究的受試者包含21 名腦膿瘍患者，13 位膠質母細胞瘤患者，以及10 位
腦部轉移腫瘤患者，經統計病灶體積平均值分別是19.5 cm3、47.3 cm3、29.4 cm3，ILSS體積平均值分別是1.0 cm3、5.3 cm3、2.5 cm3，比例平均值分別是7.1 %、11.8%、8.8 %。腦膿瘍的病灶與ILSS 體積、比例明顯皆為三類中最低。膠質母細胞瘤的病灶與ILSS 體積、比例皆為三類中最高，且數據分布範圍較為散佈。腦部轉移腫瘤的病灶與ILSS 體積、比例皆介於其他兩類之間，且數據分布較為極端。

Susceptibility-weighted imaging (SWI) has been used to enhance the variation of
magnetic susceptibility among human tissues and is very sensitive to the accumulation of paramagnetic compounds like hemorrhage, which is in appearance of low gray levels in SWI. In this study, an objective method was proposed to determine the intra-lesional susceptibility signal (ILSS) for ring-enhanced lesions. The procedure of image processing can be divided into three steps, including selection of region of interest (ROI) on post-contrast images, Ostu’s segmentation of the lesion, and determination of ILSS by using normalized difference, in which the information from non-ILSS and normal
white matter was considered. Therefore, the volume of ILSS and lesion, and the
corresponding ratio, can be measured.

A total of 44 subjects, including 21 with abscess, 13 with glioblastoma
multiforme(GBM), and 10 with brain metastasis, was enrolled in this study. For abscess, GBM, and metastasis, the mean volume of ILSS is 1.0cm3 , 5.3 cm3 , and 2.5 cm3 and the mean lesion size is 19.5 cm3 , 47.3 cm3 , and 29.4 cm3 , respectively, and the corresponding ratio on average is 7.1%, 11.8%, and 8.8%. As a result, the volume of ILSS and lesion, and the ratio of abscess are obviously the smallest among three types of ring-enhanced lesions when GBM has the largest numbers. In comparison, the statistical results of brain metastasis were found between abscess and GBM with a comparatively small simple size of ten.

論文審定書 i
致謝 ii
摘要 iii
Abstract iv
目錄 v
圖目錄 vi
表目錄 vii
第一章 介紹 1
1.1 背景 1
1.2 研究目的 6
第二章 實驗方法 9
2.1 磁化率權重影像原理 9
2.2 造影參數與影像處理 14
2.3 圈選ROI 16
2.4 影像分割 20
2.5 找出ILSS 23
第三章 結果 25
3.1 影像處理結果 25
3.2 統計分析 35
第四章 討論與結論 42
4.1 SWI成像條件的選擇 42
4.2 SWI影像處理與ILSS判斷 45
4.3 結論 49
參考文獻 50

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