Author: Cash Horn
Ultrasound CT MRCP or T2 MRI - T1 (pre- and/or post-contrast) ERCP Gross Histology Additional comments
Biliary IPMT Segmental "aneurysmal" dilatation of bile ducts. May see echogenic nodular intraductal mass (pictured), anechoic intraductal mucin Markedly dilated bile ducts (arrows) associated with enhancing, intraluminal papillary or nodular mass (arrowheads) Diffuse or segmental "aneurysmal" biliary ductal dilatation (arrows), +/- intraductal filling defects (from tumor) Dilatation of the biliary tree with intraluminal filling defects representing mucin (straight arrow) or tumor Dilated mucin-filled ducts lined by innumerable frondlike papillary infoldings. Can be multilocular and cystic Papillary proliferation consisting of columnar epithelial cells lining a fibrovascular core (arrows). Can range from adenoma or dysplasia to invasive adenocarcinoma Dilated ducts distal to the tumor due to excessive mucin secretion and distal impaction.
Cholangiocarcinoma Tumor is difficult to visualize, usually isoechoic to liver; dilated ducts up to the level of the tumor; may see intraductal mass (image) Portal venous phase shows an ill-defined mass (arrow) with associated biliary dilatation (arrowheads) Obstructing hilar stricture (arrow) with proximal dilated ducts MR images obtained following the administration of gadolinium contrast shows progressive enhancement of the tumor +/- high signal dilated ducts. Long, irregular stricture with asymmetric narrowing +/- intraductal mass with proximal bile duct dilatation Usually grouped into three types: infiltrative (periductal, shown), exophytic (mass-forming), and polypoid (intraductal). See thickening of the bile duct walls (arrows) and dilatation of the adjacent ducts (arrowheads) Usually adenocarcinoma (arrow) with infiltrating desmoplastic reaction. Multiple histological types including ductal, papillary, mucinous, adensquamous, and squamous
Biliary cystadenoma/ cystadenocarcinoma Multiloculated intrahepatic cystic mass (occasionally unilocular) +/- internal echoes, septa, or mural nodule(s) (seen in this image) Uni- or multilocular cystic mass with enhancement of cyst capsule, internal septations, and/or mural nodule (arrowhead) Large, fluid-filled (high-intensity) intrahepatic mass (solid arrow). Filling defects within the mass are from a polypoid mural nodule, and low-signal filling defects within the dilated common hepatic duct (open arrow) is related to mucin secretion by the mass Variable signal of cysts depending on content of cystic fluid. High-signal intensity as seen in the large cyst in this image (*) suggests mucoid or hemorrhagic components. Smaller cysts in this image with low signal intensity suggest serous fluid. Post-contrast images demonstrate enhancement of the capsule and septa May show communication of the cystadenoma with the biliary system (arrow). +/- bile duct obstruction due to excessive mucin production Multiloculated cystic tumor containing serous, mucinous, or hemorrhagic fluid Single layer of cuboidal or columnar epithelial cells lining the wall of the cyst. Can see malignant epithelial cells in cystadenocarcinoma Calcifications. Occur primarily in middle-aged women
Choledocholithiasis Echogenic stone (arrows) with posterior shadowing (lines) in CBD. +/- ductal dilatation Stone in CBD, which varies in density from hypo- to hyperdense depending on composition. May see "Bull's-eye" sign (arrowhead), a rim of water-density bile surrounding the obstructing stone. +/- bile duct/CBD dilatation Low-signal filling defect within CBD representing the stone (arrow) surrounded by high-signal bile Single or multiple filling defects within the opacified CBD Stones may be made of calcium bilirubinate, cholesterol, or mixed. Purely cholesterol stones (~10%) are low density and difficult to visualize on CT.
Ascending cholangitis Duct dilatation associated with thickening of the duct walls. +/- intraductal echogenic material (purulent bile) or stones Dilatation of intra- and extrahepatic bile ducts with wall thickening and high density layering intraductal purulent bile (arrowhead) Bile duct dilatation +/- stones (low signal) or strictures (arrowhead), in this case caused by an extrahepatic cholangiocarcinoma Hypointense dilated bile ducts with wall thickening that enhances with contrast (arrow), +/- stones (low signal) or strictures Dilated intra- and extrahepatic ducts +/- fililng defects caused by stones (arrow) or strictures CBD obstruction by a stone (choledocholithiasis) is the most common cause (~80%) of ascending cholangitis. Therefore, all of the described imagining findings may be seen in association with a CBD stone. Complications include hepatic abscesses, portal vein thrombosis, and biliary peritonitis.
Recurrent pyogenic cholangitis Dilated intrahepatic ducts with echogenic intraductal material +/- accoustic shadow (sludge or stones), often associated with marked atrophy of the involved liver segment which causes the ducts to appear close to the liver edge Dilated intra- and extrahepatic bile ducts which may be associated with segmental atrophy of the involved liver segment (image) or liver abscesses Dilated ducts with intrahepatic hypointense filling defects (stones, arrowheads) Segmental dilated bile ducts (hypointense) with intermediate-signal density intraductal stones +/- periductal enhancement (arrow) Dilated ducts with filling defects (stones). May see "arrowhead" sign which results from rapid duct tapering (arrows) Dilatation of the ducts with small brown intraductal stones; may see atrophy of the involved liver segment Common in East Asian populations; thought to be associated with Clonorchis infection. Can occur in any patient with biliary stasis, leading to development of pigment stones. Segmental distribution with predilection for lateral segment of left lobe of the liver.
Primary Sclerosing Cholangitis Marked ductal wall thickening and segmental ductal dilatation Scattered, dilated bile ducts associated with duct wall thickening. Can see hypertrophy of caudate lobe with peripheral atrophy (arrow) in end-stage PSC Randomly distributed annular bile duct strictures alternating with normal or slightly dilated segments to produce a 'beaded' appearance Multiple segmental strictures of both intra- and extra-hepatic ducts causing 'beaded' appearance (arrows). With worsening fibrosis, the ducts become obliterated and the peripheral ducts cannot be visualized Segmental ductal dilatation and strictures with periductal fibrosis; intraductal calculi (curved arrows) Extensive concentric periductal fibrosis (this image from a patient who had secondary sclerosing cholangitis from chronic obstruction, which is histologically indistinguishable from primary) Progressive fibrosis of both intra- and extra-hepatic ducts. 60-80% of patient's with PSC have IBD, especially UC. Increased risk of cholangiocarcinoma.
Choledochal Cysts (Types I-IV) Type 1 choledochal cyst shows fusiform dilatation of the common bile duct CECT shows cystic dilatation of the terminal CBD protruding into the duodenum, compatible with a choledochocele (type III choledochal cyst) Bile is hyperintense. Image shows multiple cystic dilatations of the bile ducts with both intra and extra hepatic components, compatible with type IV choledochal cysts Contrast material seen filling a cystic dilatation of the papillary portion of the CBD, consistent with a choledochocele (type III choledochal cyst) Saccular dilatation of the common bile duct (arrow) compatible with type 1 choledochal cyst, shown in continuity with the cystic duct and the gallbladder (arrowhead) Type I: Fusiform dilatation of the extrahepatic duct
Type II: Diverticular outpouching of the extrahepatic duct
Type III: Choledochocele (dilatation of the distal intraduodenal portion of the CBD)
Type IV: Multifocal dilatations of the intra- and extra-hepatic bile ducts
Type V: Caroli's disease
Caroli Disease Dilated intrahepatic ducts +/- stones Saccular dilatation of the intrahepatic bile ducts with the central dot sign, caused by portal radicals being completely surrounded by the dilated bile ducts (arrow) +/- stones

Multiple stones (arrowheads) within multiple cystic dilatations of the intrahepatic bile ducts
Multiple hyperintense cystic dilatations of the intrahepatic bile ducts; stones are seen as hypointense filling defects (arrow) Saccular dilatation of intrahepatic bile ducts Saccular dilatations of intrahepatic bile ducts Dilated intrahepatic ducts +/- intraductal stones (arrow)
Hamartoma (von Meyenburg complex) Multiple small lesions throughout the liver; may be hypo-, iso-, or hyperechoic depending on makeup (cystic vs solid, no image shown) Multiple hypodense round lesions measuring up to 1.5 cm, ranging from fluid-density (cystic) to soft-tissue density (fibrous stroma) depending on cystic/solid components Multiple hyperintense nodules without communication to the bile ducts Multiple nonenhancing hypointense lesions No communication of hamartomas with biliary tree, so will see normal bile duct anatomy (no image shown) Multiple cystic lesions in the hepatic parenchyma measuring up to 1.5 cm; can range from cystic (shown) to solid Disorganized bile ducts and fibrocollagenous stroma, without communication to the biliary system
Peribiliary Cysts Anechoic cystic structures in region of hilar biliary ducts Well-defined, fluid-density tubular or round structures surrounding the hilar portal tracts of the liver Markedly hyperintense cystic or tubular lesions along portal tracts in region of the liver hilum (T2 MRI shown) No communication of cysts with biliary tree (not visualized, no image shown)
Ampullary carcinoma Dilated pancreatic and common bile duct (arrow) Nodular mass of varying density at the papilla protruding into the duodenum (arrow) with pancreatic and biliary ductal dilatation "Double-duct sign"- dilated CBD and pancreatic ducts +/- bulging mass protruding into distal CBD (shown) Dilated CBD and pancreatic duct +/- visible ampullary mass Soft tissue nodular mass arising from ampulla Dysplasia or frank adenocarcinoma of ductal epithelial cells Indistinguishable from ampullary adenoma on imaging studies
AIDS Cholangiopathy Ductal dilatation and wall thickening of CBD (pictured) and intrahepatic ducts Spectrum of biliary disease caused by opportunistic AIDS infections