Usefulness of Curved Multiplanar Reformatted Images of Multi-detector CT for Differentiation of Biliary Stent Obstruction in Malignant Biliary Obstruction Patients

초록

Biliary stent obstruction is caused by biliary sludge clogging, or tissue ingrowth such as tumor ingrowth or epithelial hyperplasia. Until now, there is no way to predict the etiology of biliary stent obstruction by noninvasive methods. We evaluate the usefulness of curved multiplanar reformatted (MPR) images of multi-detector CT (MDCT) for the noninvasive assessment of cause of biliary stent obstruction. Methods: From December 2004 to July 2007, among malignant biliary obstruction patients who had undergone biliary stent insertion, 15 patients who were suspected of biliary stent obstruction and underwent ERCP after MDCT were enrolled. Curved MPR images were obtained along the pathway of biliary stent. We defined as contrast-enhancement when the Hounsfield unit (HU) is increased over 10 HU comparing pre- and post-contrast CT scan at the region of interest inside the biliary stent, and read as tissue ingrowth or biliary sludge clogging whether it is increased or not. We confirmed the presence of obstruction in biliay stent and whether tissue ingrowth or biliary sludge clogging using ERCP and then compared with MDCT finding. Results: Among 6 patients who were read as tissue ingrowth on MDCT, 5 patients were diagnosed as tissue ingrowth on ERCP. Among 9 patients who were read as biliary sludge clogging on MDCT, 8 patients were diagnosed as biliary sludge clogging on ERCP. The diagnosis of MDCT and ERCP was the same except for 2 patients. The sensitivity and specificity of MDCT for tissue ingrowth is 83.3% and 88.9% respectively. Conclusion: Curved MPR image of MDCT is a useful noninvasive modality for the prediction of etiology of biliary stent obstruction and it is helpful to plan for the medical management of such patients.