十二指肠壶腹部肿瘤影像诊断与鉴别诊断

,Benign and Malignant Ampullary and Periampullary Lesions,Anatomy,1. Located in the major duodenal papilla2.Represents the junction of the common bile duct (CBD) and main pancreatic duct,Anatomy,Three types of joining of the CBD and main pancreatic duct 1.the CBD and main pancreatic duct join to form a common channel that is 18 mm in length 2.a common channel is not present instead there is a single orifice in the papilla that contains a separate opening for each duct 3.two separate orifices in the papilla that drain the CBD and main pancreatic duct separately,Anatomy,Sphincter of Oddi：The ampulla of Vater is surrounded by the sphincter of Oddi, a 1-cm structure composed of smooth muscle that regulates the flow of bile and pancreatic juices into the duodenum.,Ampullary and Periampullary Neoplasms1.Ampullary Adenocarcinoma2.Ampullary Adenoma3.Distal CBD Cholangiocarcinoma4.Duodenal Adenocarcinoma5.Gastrointestinal Stromal Tumor6.Pancreatic Adenocarcinoma7.Pancreatic Neuroendocrine Tumor,Non-neoplastic Lesions1.Papillary Stenosis2.Choledocholithiasis3.Pancreatic Divisum4.Groove Pancreatitis5.Autoimmune Pancreatitis and IgG4-related Sclerosing Cholangitis6.Pancreaticoduodenal Artery Pseudoaneurysm7.Duodenal Crohn Disease,Ampullary adenocarcinoma,Imaging Findings1.Irregular nodular mass at the distal margin of the pancreaticobiliary junction2.Enhancement on arterial and portal venous phase 3.Lobulated or infiltrating borders4.At MRCP，typically manifest as a filling defect or focal stricture5.Dilatation of both the biliary and pancreatic ducts,（a）,（b）,Ampullary Adenoma,Imaging Findings 1. An ampullary soft-tissue mass greater than 1 cm2.Irregular margin of the ampulla3.Extrahepatic biliary duct dilatation, and pancreatic duct dilatation4. May undergo malignant transformation into adenocarcinoma,Distal CBD Cholangiocarcinoma,Imaging Findings 1.Two subtypes of extrahepatic cholangiocarcinoma： （1）Infiltratings：ductal wall thickening and sudden luminal obliteration （2）polypoid:at imaging as an intraductal polypoid mass that typically does not cause complete obstruction 2.Hypointense relative to the liver parenchyma on T1-weighted MR images and hyperintense on T2-weighted MR images 3.Homogeneous slow enhancemen,(b),(a),(c),Duodenal Adenocarcinoma,Imaging Findings 1. Either a polypoid or intraluminal mass, with eccentric duodenal wall thickening 2.More commonly involves a relatively short segment of the bowel 3.If ampullary involvement, biliary dilatation may be seen 4.Relatively hypovascular,（a）,（b）,Gastrointestinal Stromal Tumor,Intramural or intraluminal vary from small homogeneous masses to large necrotic massesEndophytic or exophytic to the bowel,Pancreatic Adenocarcinoma,1.On T1WI the tumor is hypointense ，On T2WI, the tumor is minimally hypointense relative to the pancreas2. Heterogeneously enhancing lesion 3.Decreased enhancement relative to the pancreas on arterial phase， and progressively enhances on more delayed phase,Pancreatic Neuroendocrine Tumor,Imaging Findings 1.They are hypoattenuating on nonenhanced CT images2. hypointense on fat-suppresse