Describe imaging features of four cases diagnosed with cystic biliary atresia micmicking choledocal cyst on MRI

Abstract

Purpose: to describle in detail the significant signs in hepatobiliary MRI, that help to give different diagnosis between biliary atresia (BA) with big cyst at hepatic hilar and choledochal cyst in small childrent and infant.Method: presenting 4 cases with clinical diagnosed of biliary atresia that based on clinical signs and US, MRI results, all 4 cases were operated, taken cholangiogram in surgery to confirm the diagnosis of cystic biliary atresia and had pathological results.Results: All 4 patients were under 3 months old, all are female with enlarged liver; gallbladder were in the normal size limit but all of them had abnormal shape: deformation, irregular wall, communicated directly with common bile duct. All 4 cases have cystic diameter over 10mm. No case of all has further biliary signal that above or under the cyst on MRI but one case has contrast material filling intraliver bile duct draining directly to cystic lesion on cholangiogram intraoperation . These are 3 cases of cystic BA type III and 1 cases of cystic BA type I. 2 cases has positive triangular cord sign (TC sign).Conclusion: Hepatobiliary MRI with its basic sequences, specially with MRCP is helpful to give difirential diagnosis of cystic BA and choledochal cyst in the young childrent.