- 學位論文
經靜脈注射Gd-DTPA對以擴散磁振加權影像來評估肝細胞病變效果之影響
Effect of Intravenous Gadolinium-DTPA on Diffusion-Weighted MR Images for Evaluation of Focal Hepatic Lesions
摘要
擴散磁振加權造影通常使用在磁振對比劑注射之前，但有時候在注射完對比劑之後有必要重複做擴散磁振加權造影，過去並無文獻報告注射對比劑對於擴散加權影像的影響，此篇主要的目的在評估注射對比劑Gadolinium－DTPA（Gd-DTPA）是否對擴散磁振加權造影及表面擴散係數（apparent diffusion coefficient；ADC）有顯著性差異。 我們此次的研究是以20位罹患局部肝臟病變的患者（平均年齡68歲；年齡分布介於33到86歲之間），使用3.0 T 磁振造影術進行檢查評估。在掃描病患時我們使用single-shot echo-planar imaging及擴散敏感係數b值等於500 s/mm2來得到擴散磁振加權影像。在注射Gd-DTPA劑量方面是0.1 mmol/kg Gd-DTPA。在此實驗中我們也測量病灶的訊雜比（signal-to-noise ratio；SNR）及對雜比（contrast-to-noise ratio；CNR），另外藉由擴散磁振加權影像來計算注射對比劑前、後的表面擴散係數並加以比較。注射對比劑前後和病灶的訊雜比及對雜比在統計上使用Student’s paired two-tailed t test。 不同的肝臟病變在注射對比劑之後表面擴散係數的值會下降但與注射前無顯著性差異 ( p = 0.097)。此實驗中發現訊雜比及對雜比在注射對比劑前後並無顯著差異（ p ＞ 0.05）；故在注射對比劑之後進行擴散磁振加權影像是可行的。
並列摘要
Diffusion-weighted imaging (DWI) is usually done before administration of intravenous magnetic resonance（MR） contrast agents. Repetition of DWI is occasionally necessary after contrast administration, but the effects of contrast material on DWI and apparent diffusion coefficient (ADC) values have not yet been fully examined. The purpose of this research is to assess whether administration of contrast material of gadopentetate dimeglumine（Gd-DTPA） significantly affects DWI and ADC values. We examined DWI by 3.0 T scanner in 20 consecutive patients (mean age, 68 years; range, 33 to 86 years) who were evaluated with a liver protocol at our hospital. All patients were scanned for the hepatic lesion. We obtained DWI using single-shot echo-planar imaging with a b value of 500s/mm2. Patients were injected with 0.1 mmol gadopentetate dimeglumine per 1 kg body weight. We examined the signal-to-noise ratio (SNR) of the normal liver and the hepatic lesions and evaluated the contrast-to-noise ratio (CNR) of each lesion. In addition, we compared the ADC values calculated from the DWI images before and after administration of contrast. The statistical significance of differences between pre-contrast and post-contrast administration was determined by use of a paired two-tailed t test. The signal-to-noise and contrast-to-noise ratios of the DWI were not significantly different before and after administration of the contrast agent ( p ＞ 0.05 ). The ADC values were decreased after administration of the contrast agent for different hepatic lesions ( p = 0.097). The insignificant difference of the signal-to-noise and contrast-to-noise ratios of DW MR images between pre- and post-contrast administration indicates the feasibility of post-contrast enhanced DWIs.