- 期刊
二點法（DIXON）及三點法（IDEAL）磁振影像定量脂肪之分析
Quantification of Fat Ratio Using Dixon and Ideal Magnetic Resonance Images
摘要
肝病一直是台灣頭號國病，台灣各大研究機構無不極力研究防治肝病的方法。而在肝癌三步曲中，肝炎、肝硬化、肝癌，肝炎為肝病之首先表現。然而隨著經濟發展及醫學的發達，了解脂肪肝形成原因有助於肝病之防治。脂肪肝形成原因包羅萬象，若能動態追蹤脂肪肝囤積程度，將有助於肝病之防治。我們運用脂肪樣品0－100%，以5%為間隔共配置21瓶樣品，以磁振造影之Dixon及IDEAL（Iterative Decomposition of Wat and Fat with Echo Asymmetric and Least-squares Estimation）波序進行進影，並運用ImageJ對影像進行運算。結果發現Dixon定量脂肪比例於脂肪樣品0－25%時，所測得之比例約自0上升至50%，並於超過樣品比例25%時運算之比例隨脂肪比例上升而下降。而IDEAL影像發現脂肪比例呈現線性變化，顯示脂肪比例之可信度。經討論發現Dixon在脂肪的訊號為水的三倍，即會產生經過運算時脂肪比例在25%時反折。而容易造成後序影像上定量的誤差。故若醫療院所無IDEAL可進行影像定量，須注意Dixon定量於25%轉折之問題。可再比對氫質子磁振頻譜脂肪測量得到可信之數據，進而推論出影像上之脂肪比例。
並列摘要
Liver disease has been the number one national disease in Taiwan. Taiwan's major research institutions are all strongly studied the methods for prevention and treatment of liver disease. In Hepatocellular carcinoma (HCC) trilogy, which includes hepatitis, cirrhosis, and liver cancer, the hepatitis is the first symptom of liver disease. However, with the economic development and medicine developed, the understanding of the causes of fatty liver can help to prevent and treat the liver diseases. The causes of fatty liver are all-inclusive. The dynamic tracking of the degree of fatty liver can improve the prevention and treatment of liver diseases. In this study, twenty-one bottles of samples contained 0-100% fat with 5% interval were imaged by magnetic resonance imaging (MRI) with Dixon and IDEAL ( Iterative Decomposition of Wat and Fat with Echo Asymmetric and Least-squares Estimation ) pulse sequences. The ImageJ program was used to quantification analysis the output images. The results show that the fat ratio quantified by Dixon is rose from about 0 to 50% when the fat ratio of samples are from 0 to 25%. As the fat ratio of sample higher than 25%, the measured proportion is decreased as the fat ratio increased. On the other hand, the results of IDEAL show a linear change in proportion of fat and the credibility of measured fat ratio. In discussion, we found the fat signal measured by the Dixon method is three times higher than that of water and is reflexed at 25% fat ratio after computation. This problem causes the quantitative errors in subsequent images of samples that contained fat ratio higher than 25%. Therefore, it should be noted that the quantitative problem at 25% of the Dixon method if the IDEAL image quantitative pulse sequence is not available. We can further use the 1H proton water-fat MRS method to infer the fat ratio in the image.