由於磁化率權重影像對於出血或血管增生所造成的順磁性物質累積現象具有高敏感度，因此近年常被來診斷腦部腫瘤。本研究利用前人所提出病灶內磁化率訊號(intra-lesional susceptibility signals, ILSS)量化方法，以對比雜訊比之概念自動篩選出在磁化率權重影像中病灶內低訊號之像素，進而計算ILSS體積及其佔病灶之體積比例，相較於傳統ILSS分級方法更為客觀且不受切面選擇所影響。本研究中首先使用該方法來觀察不同腫瘤分期的星狀細胞瘤(astrocytoma)之間的差異；再者，針對在傳統磁振造影中皆有可能具有環狀顯影的三類病灶，包含：腦膿瘍(brain abscess)、壞死性腦部轉移腫瘤(necrotic brain metastasis)、以及壞死性神經膠質母細胞瘤(necrotic glioblastoma multiforme)，嘗試以所提方法進行差異性分析。

研究結果發現在星狀細胞瘤中，由於高度惡性腫瘤分期病灶(WHO grade III, IV，總計36例)之ILSS體積百分比明顯高於低度惡性腫瘤分期病灶(WHO grade II，總計8例)。本研究並分析具有環狀顯影的病灶，計有腦膿瘍27例、壞死性腦部轉移腫瘤18例以及壞死性神經膠質母細胞瘤18例，發現以腦膿瘍病灶之ILSS體積百分比明顯低於壞死性神經膠質母細胞瘤，然而，壞死性腦部轉移腫瘤的ILSS百分比分布較為廣泛(0% ~ 50.42%)，因此與腦膿瘍和壞死性神經膠質母細胞瘤之間並沒有發現統計上的差異。

In recent years, susceptibility weighted imaging is broadly applied on brain tumors because of its high sensitivity to hemorrhage and increased vasculature, both leading to the accumulation of paramagnetic substances. In this study, a quantitative intra-lesional susceptibility signals (ILSS), which detects the hypointense pixels within the lesion, is used to assess the ILSS volume and its volumetric percentage of the lesion. Compared with the previously proposed ILSS score, the quantitative ILSS method is more objective and independent of slice location, so that it is applied on two approaches: the tumor grading of astrocytoma and discrimination of rim-enhanced lesions, including brain abscess, necrotic brain metastasis, and necrotic glioblastoma multiforme.

Results show that the ILSS volumetric percentage of high-grade astrocytoma (WHO grade III and IV, n = 36) is significantly higher than that of low-grade tumors (WHO grade II, n=8). In addition, the ILSS volume and percentage is analyzed on 27 brain abscesses, 18 necrotic brain metastases, and 18 necrotic glioblastoma multiforme, all of them in appearance of rim enhancement in contrast-enhanced T1WI. It is found that the volumetric percentage of abscess is significantly lower than that of necrotic glioblastoma multiforme. However, the variation of ILSS percentage is relatively higher, ranging from 0% to 50.42% , in the group of necrotic brain metastasis. As a result, no significant difference is found either in comparison with abscess or necrotic glioblastoma multiforme.

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 8
第二章 資料與方法 10
2.1 磁化率權重影像處理 10
2.2 定義ILSS 13
2.3 掃描參數 16
2.4 ILSS處理過程 19
2.5 分析方法 23
第三章 結果 24
3.1影像處理結果 24
3.2 分析結果 36
3.2.1 high-grade與low-grade 36
3.2.2 具有環狀顯影的腦膿瘍、壞死性神經膠質母細胞瘤以及壞死性腦部轉移腫瘤 39
第四章 討論與結論 43
4.1 實驗結果討論 43
4.2 ILSS體積百分比與其他方法之間的差異 44
4.3 考慮不同原生腫瘤所引起的壞死性腦部轉移腫瘤 48
4.4 結論 50
參考文獻 51

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