Curved Planar Reformatted Images of MDCT for Differentiation of Biliary Stent Occlusion in Patients With Malignant Biliary Obstruction

OBJECTIVE. We prospectively evaluated the usefulness of MDCT using a curved planar reformation technique for the noninvasive assessment of the causes of biliary stent occlusion in patients with malignant biliary obstruction. SUBJECTS AND METHODS. Between December 2004 and January 2009, 173 patients with unresectable malignant biliary obstruction underwent biliary stent insertion. Among them, 26 patients with suspected biliary stent occlusion underwent 29 sessions of ERCP within 2 weeks after MDCT was performed. Curved planar reformation images were obtained along the pathway of the biliary stent. We interpreted tissue growth or stent clogging by comparing attenuation values inside the biliary stent between the unenhanced and contrast-enhanced phases of CT. The cause of biliary stent occlusion was confirmed by using ERCP. RESULTS. The differences in attenuation value inside the biliary stent between the contrast-enhanced and unenhanced phases of CT in the tissue growth group was 27.7 +/- 21.7 HU (SD) and 4.2 +/- 10.6 HU in the stent-clogging group (p = 0.002). The sensitivity and specificity of MDCT for the diagnosis of tissue growth were 86.7% and 85.7%, respectively. The overall accuracy of curved planar reformation images of MDCT for diagnosing the causes of stent occlusion was 86.2%. CONCLUSION. Curved planar reformation MDCT is a useful noninvasive technique that is relatively accurate for diagnosing the cause of biliary stent occlusion and is helpful for planning the therapeutic management of such patients.