CT and MR imaging findings of biliary cholelithiasis and acute cholangitis

Abstract

While normal bile juice show hypointensity on T1-weighted MR imaging (T1WI), concentrated bile juice within the gallbladder may show hyperintensity on T1WI and hypointensity on MR cholangiopancreatography (MRCP). So MRCP sometimes cannot clearly illustrate the gallbladder with concentrated bile juice. The hepatic segment having biliary cholestasis by intrahepatic bile duct obstruction may show hyperintensity on T1WI. Imaging diagnosis by ultrasound and CT of intrahepatic bile duct stones is frequently difficult if lacking calcium deposition. Intrahepatic stone is frequently bilirubin calcium calculus shows hyperintensity on T1WI. MRI is useful for the correct diagnosis of intrahepatic stone. The most characteristic imaging feature of acute cholangitis is transient inhomogeneous hepatic contrast enhancement on arterial dominant phase of dynamic CT and dynamic MRI. Other findings of acute cholangitis are bile duct wall thinking wit contrast enhancement, periportal hyperintensity on T2-weighted imaging, inhomogeneous hyperintensity of the hepatic parenchyma on diffusion weighted imaging.