What does this mean:

gallbladder is surgically absent. the systic duct is cannulated. the extrahepatic bile and central intrahepetic bile ducts are well-opacidfied. there is a persistent subcentimeter rounded filling defect present within the common bile duct just above the level of the ampulla, consisten with an intraductal calculus. there is spillage of contrast material into the duodenum. no suspicious extraluminal leakage of contrast noted