3T MRI單次閉氣之膽道胰管磁振造影：比較3D GRASE 及 2D FSE 成像結果

Abstract

我們利用3T磁振造影儀，比較兩種不同序列所呈現出的膽道胰管影像(MRCP)，在不同位置其清晰程度差異性比較分析。所採用的兩種序列分別為gradient- and spin-echo (GRASE) 3D影像，以及thick-slab fast spin-echo (FSE) 2D影像。全部受檢測者總共為95人(男/女 = 49:46，年齡介於 25-75歲)，3T磁振造影參數調校以一次呼吸閉氣的時間內能夠完成影像，且不超過組織安全可曝露能量(SAR)的上限值為原則。膽道及胰管依解剖構造分為八個區段來比較影像呈現，依是否符合臨床診斷所能接受之影像品質，採用4個等第分類。 在總膽管、總肝管區段，3D GRASE MRCP 的表現比2D FSE MRCP 來得好 (兩者p < 0.001)，在右前肝內膽管(p < 0.001)、右後肝內膽管(p < 0.005) 、胰管遠段 (p < 0.05)區域，則為2D FSE MRCP比3D GRASE MRCP 的表現好。另外可以發現同時合併這兩個序列的影像一起判讀，左肝內膽管無法診斷的情形可以減少至10個受測者(5.3%)，而原本3D GRASE MRCP有31個(16.3%)受測者左肝內膽管無法診斷，2D FSE MRCP有21個(11.1%)受測者左肝內膽管無法診斷。 儘管在單一次呼吸閉氣的MRCP檢查中，3D GRASE MRCP 對於總膽管及總肝管的診斷較為有利，但2D FSE MRCP在較小管徑的位置仍舊有較好的表現，兩者為互補性的關係。

We compare the depiction conspicuity of three-dimensional (3D) magnetic resonance cholangiopancreatography (MRCP) based on gradient- and spin-echo (GRASE) and two-dimensional (2D) thick-slab MRCP using fast spin-echo (FSE) in different segments of hepatic and pancreatic ducts at 3T. There were 95 subjects (M/F = 49:46, age range = 25-75) performed for at 3T. The parameters are adjusted under the constraints of specific absorption rate and scan time within single breath-hold. Conspicuity of eight ductal segments was graded by two experienced raters using a 4-point score. 3D GRASE MRCP outperformed 2D thick-slab FSE MRCP in the common bile duct and common hepatic duct (both with p < 0.001), but compared inferiorly in the right anterior hepatic duct (p < 0.001), right posterior hepatic duct (p < 0.005) and pancreatic duct distal (p < 0.05). Performing both 3D and 2D MRCP would reduce the number of non-diagnostic readings in the left hepatic duct to 10 remaining (5.3%), compared with 31 (16.3%) or 21 (11.1%) out of 190 readings if using 3D GRASE or 2D thick-slab FSE alone, respectively. Although 3D GRASE MRCP is preferential to visualize the common bile duct and common hepatic duct within one single breath-hold, the complementary role of 2D thick-slab FSE MRCP in smaller hepatic and pancreatic ducts makes it a useful adjunct if performed additionally.