胆管扩张时线条样假性充盈缺损病变的磁共振胰胆管成像(MRCP)表现及意义

Appearance and significance of linear false filling defect in dilated bile ducts on MR cholangiopancreatography

目的 探讨MRCP中胆管内线条样充盈缺损的表现及成因。方法 分析 3 0 0例胆总管扩张病人和 5 0例正常人的MRCP ,所见与轴位T2WI、T1WI、B超及ERCP检查和 (或 )手术相对照。结果 MRCP图像中胆总管内线条样充盈缺损见于中 重度扩张胆总管 ,但B超、ERCP检查和外科手术未能证实其存在。结论 MRCP图像中扩张胆总管中央的线条样低信号很可能是由胆汁流动形成的假性病变或伪影。

Objective To investigate MR cholangiopancreatography (MRCP) appearance and influencing factors of linear filling defect in dilated bile ducts. Methods Three hundred patients with common bile duct (CBD) dilatation and 50 normal subjects underwent MRI examination, including MRCP, axial T1WI and T2WI. For MRCP, the coronal source images were produced by three-dimensional fast spin-echo sequence, then reconstructed into 12 images with maximum intensity projection (MIP) method. The findings on MRCP were correlated with that of axial T1WI and T2WI, ultrasonography, endoscopic retrograde cholangiopancreatography (ERCP) and/or surgical operation. Results The diameter range of CBD was 8.5-30 mm in the patient group. No filling defect was visible in 40 low-grade dilatation cases, nor in the 50 normal subjects. In 113 medium-grade dilatation cases, a linear hypointensity was seen on MRCP in 17 cases (15.04%), and a round hypointensity was seen on T2WI in 1 case (0.88%), while in high-grade dilatation was seen in 38 (25.85%) on MRCP, and in 3 (2.04%) on T2WI, respectively. These filling defects were parallel to the CBD wall on MRCP and at the center of CBD on T2WI, surrounding by hyperintensity of bile, but couldn't be proved by ultrasonography, ERCP and/or surgery. Conclusion Linear hypointensity in dilated bile ducts on MRCP was most likely pseudolesion or flow-related artifact probably caused by bile flow.