MR Imaging Findings of Clonorchiasis patients (Fig. 1). Wall enhancement and thickening were identified in 21 (81%) patients (Fig. 2), and filling defects (Fig. 3) and ductal stricture in 6 (24%) and 3 (12%), respectively. Extrahepatic bile duct abnormalities were seen in 7 (27%) of the 26 patients. The most common finding was wall enhancement of the common bile duct, which was present in 5 (24%) patients with cholangiocarcinoma (Fig. 4). Extrahepatic ductal dilation was found in 5 (19%) of 26 patients. Marked dilation was seen in one patient who had a carcinoma in the common bile duct. Nine (35%) patients revealed a hepatobiliary malignancy. In these patients, 7 (27%) had a cholangiocar- cinoma; 3 in the hilar portion, 2 in the common bile duct and 2 in the intrahepatic ducts. One patient had combined Table 1. MR Findings in 26 Patients with Clonorchiasis MR Findings Intrahepatic bile duct Ductal dilatation Mild / Marked “Too many intrahepatic ducts” sign Wall enhancement Wall thickening Filling defect Ductal stricture Extrahepatic bile duct Ductal dilatation Mild / Marked Wall enhancement Wall thickening Filling defect Ductal stricture Note. Two cases have cholangiocarcinoma. No. of Patients (%) 23 (89) 23 (89) 21 (81) / 2 (8) 16 (62) 21 (81) 21 (81) 06 (24) 03 (12) 08 (31) 05 (19) 4 (15) / 1 (4) 06 (24) 06 (24) 2 (8) 2(8) tumors (distal common bile duct carcinoma and hepatocel- lular carcinoma). Of the 3 patients with a hepatocellular carcinoma, two had liver cirrhosis caused by the hepatitis B virus or alcoholic liver cirrhosis. In 9 patients that had undergone ERCP, intrahepatic bile duct abnormalities (ductal dilatation, n = 9; “too many intrahepatic ducts” sign, n = 9; ductal stricture, n = 7; and filling defect, n = 2) were found. MR imaging showed evidence of intrahepatic abnormalities in all patients. Ductal dilation was shown in all patients. “Too many intrahepatic ducts” sign was seen in 7 of the 9 patients. However, ductal stricture was observed on the MR imaging in 5 of the 9 patients, which was less than that found on ERCP. A filling defect was observed on MR imaging in 4 of the 9 patients, which was more than that Fig. 1. Clonorchiasis in a 49-year-old man. Coronal single-shot fast spin echo MR cholangiogram (TR/effective TE= /800, 40- mm section thickness) shows too many intrahepatic bile ducts, without dilatation of extrahepatic bile duct. Focal stricture (arrow) is seen in the left intrahepatic bile duct. A B Fig. 2. Clonorchiasis in a 58-year-old man. Gadolinium-enhanced echo fast gradient echo 3D (TR/TE, 7/2) transverse (A) and coronal (B) images show periductal enhancement of mildly dilated intrahepatic bile duct (arrows). There is no dilatation of extrahepatic bile duct. Korean J Radiol 5(1), March 2004 27