Imaging of the intrabiliary rupture of hepatic bydatid cysts

Abstract

Objective To discuss the imaging features of ultrasonography (USG), CT /CT cholangiography (CTC)、MR/MR cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP) of the hepatic hydatid cysts ruptured into biliary duct, and to evaluate the diagnostic efficacy of different modalities. Methods Fifty one cases of hepatic hydatid cysts with intrabiliary rapture were divided into 4 groups according to imaging modality used to study these cases. 46 cases, 41 cases, 35 cases and 14 cases were examined by USG, CT, MRCP and ERCP respectively. Comparison of the imaging findings from different imagng modalities with surgical results were made to evaluate the efficacy of each imaging modality. Analysis of X2 were performed for the positive predictive value among the 4 groups. Results The positive predictive values of these four methods in diagnosing the intrabiliary rupture of liver hydatid cyst were 67.4% (31/46), 80. 5% (33/41), 94. 3% (33/35)and 100. 0% (14/14) respectively(X2=13. 1370,P<0. 05). There were statistical difference between USG and MRCP (P <0. 0084). The direct manifestations of intrabiliary rupture of hepatic hydatid cysts on USG,CT、 MRCP and ERCP were as following: (1) Communication break point was seen in 3/46.3/41,9/35 and 13/14 cases respectively;(2) Increased biliary density due to the presence of membrane of echinococcus cysts and daughter cysts were seen in 5/46, 6/41,6/35 and 8/14 cases respectively;(3) Lesions adjacent to bile duct, gall bladder wall thickening, and/or interruption of bile duct, remote biliary dilatation were seen in 24/46, 26/41,31/35 and 8/14 of cases respectively. Indirect signs included: (1) Cyst collapse, increased cyst fluid density were seen in 30/46, 33/41, 27/35 and 0/14 of cases respectively;(2) Detached membrane signs were seen in 21/46, 24/41,22/35 and 0/14;(3) Dilatation of adjacent hepatic bile duct were seen in 30/46, 29/41, 34/35 and 6/14 of cases respectively. Conclusions Both USG and CTC could accurately detect the signs of intrabiliary rupture of hepatic hydatid cysts;MRCP is an effective and noninvasive diagnostic tool ;ERCP is the gold standard in confirming intrabiliary rupture of liver hydatid disease. Key words: Liver diseases; parasitic; Echinoeoccosis; hepatic; Biliary tract