Meakem T J, Schnall M D
Cape Fear Valley Medical Center, Fayetteville, North Carolina.
Gastroenterol Clin North Am. 1995 Jun;24(2):221-38.
MR cholangiography offers a noninvasive method of obtaining images of the biliary system without the use of a contrast agent. There is no radiation exposure. Pulse sequences can be chosen to obtain bright bile or black bile cholangiograms. Image processing algorithms can be selected to obtain a three-dimensional representation of biliary anatomy and pathology, and those images can be rotated in any plane so that ductal anatomy and pathology can be seen to best advantage. In patients with a nonobstructed biliary system, the RHD, LHD, CHD, CBD, and distal PD are usually visible. In patients with choledocholithiasis, the CE-FAST technique has demonstrated higher diagnostic accuracy than the FSE approach, although TRAP image reconstruction probably would improve the accuracy of the FSE technique in detecting stones. In patients with malignant biliary obstruction, FSE is considerably more accurate in determining the cause of obstruction than is CE-FAST. Furthermore, MR cholangiography compares favorably with ERCP, prompting one author to suggest that, in selected patients, MR cholangiography might be used instead of direct cholangiography or to direct invasive techniques. With continued technologic advancements, MR cholangiography will no doubt improve as well. In particular, the possibility of a breath-hold, multicoil, FSE cholangiogram, obtained with the stronger gradients on an echo planar system, potentially combines the key advantages of CE-FAST and conventional FSE techniques. It may be that in the not-too-distant future, all patients with obstructive jaundice will be imaged first with MR imaging. In addition to the typical axial images of the abdomen required for staging, an MR cholangiogram will be obtained in a matter of a few seconds. An MR angiogram will also be performed to determine vascular anatomy and pathology. MR spectroscopy might also be used to obtain additional diagnostic information. All of this would be done in less than an hour, noninvasively, and with no radiation. Some patients would then require percutaneous transhepatic cholangiography or ERCP. Others would undergo MR-guided biopsy. Eventually, still other patients might go directly to surgery.
磁共振胆胰管造影提供了一种无需使用造影剂即可获取胆道系统图像的非侵入性方法。不存在辐射暴露。可以选择脉冲序列来获得明亮胆汁或黑色胆汁的胆管造影图像。可以选择图像处理算法来获得胆道解剖结构和病变的三维表示，并且这些图像可以在任何平面上旋转，以便能以最佳视角观察胆管解剖结构和病变。在胆道系统无梗阻的患者中，右肝管、左肝管、肝总管、胆总管和胰管远端通常可见。在胆总管结石患者中，CE-FAST技术已证明比FSE方法具有更高的诊断准确性，尽管TRAP图像重建可能会提高FSE技术检测结石的准确性。在恶性胆道梗阻患者中，FSE在确定梗阻原因方面比CE-FAST准确得多。此外，磁共振胆胰管造影与内镜逆行胰胆管造影（ERCP）相比具有优势，促使一位作者提出，在某些选定的患者中，磁共振胆胰管造影可替代直接胆管造影或指导侵入性技术。随着技术的不断进步，磁共振胆胰管造影无疑也会得到改善。特别是，在回波平面系统上利用更强的梯度获得屏气、多线圈FSE胆管造影的可能性，有可能结合CE-FAST和传统FSE技术的关键优势。也许在不久的将来，所有梗阻性黄疸患者都将首先接受磁共振成像检查。除了分期所需的典型腹部轴位图像外，几秒钟内就能获得磁共振胆胰管造影图像。还将进行磁共振血管造影以确定血管解剖结构和病变。磁共振波谱分析也可能用于获取更多的诊断信息。所有这些都可以在不到一小时的时间内无创完成，且无辐射。然后，一些患者可能需要经皮肝穿刺胆管造影或ERCP。其他患者将接受磁共振引导下的活检。最终，还有一些患者可能直接进行手术。
