Ultrasound of the bile ducts

Update on Treatment Options for Advanced Bile Duct Tumours: Radioembolisation for Advanced Cholangiocarcinoma

Cholangiocarcinoma is a rare form of gastrointestinal cancer with a poor prognosis. Patients often present with biliary obstruction or non-specific abdominal pain, and a high proportion of patients have advanced disease at initial diagnosis. The goal of this review is to discuss treatment options for patients with advanced bile duct tumours focusing on radioembolisation (RE) and its impact on overall survival. RE provides a therapeutic option for patients with unresectable cholangiocarcinoma. However, although systemic chemotherapy has demonstrated a survival benefit in randomised controlled trials, there is limited supporting evidence for the use of RE in this setting. Studies are mostly limited to single-centre, small cohorts with variable outcome measures. Additionally, patients included in these studies received a variety of previous therapies including chemotherapy, surgery or alternative intra-arterial therapy; therefore, a true assessment of overall survival benefit is difficult.

Intrahepatic cholangiocarcinoma: current perspectives

Intrahepatic cholangiocarcinoma (ICC) is the second most common malignancy arising from the liver. ICC makes up about 10% of all cholangiocarcinomas. It arises from the peripheral bile ducts within the liver parenchyma, proximal to the secondary biliary radicals. Histologically, the majority of ICCs are adenocarcinomas. Only a minority of patients (15%) present with resectable disease, with a median survival of less than 3 years. Multidisciplinary management of ICC is complicated by large differences in disease course for individual patients both across and within tumor stages. Risk models and nomograms have been developed to more accurately predict survival of individual patients based on clinical parameters. Predictive risk factors are necessary to improve patient selection for systemic treatments. Molecular differences between tumors, such as in the epidermal growth factor receptor status, are promising, but their clinical applicability should be validated. For patients with locally advanced disease, several treatment strategies are being evaluated. Both hepatic arterial infusion chemotherapy with floxuridine and yttrium-90 embolization aim to downstage locally advanced ICC. Selected patients have resectable disease after downstaging, and other patients might benefit because of postponing widespread dissemination and biliary obstruction.

Varying appearances of cholangiocarcinoma: radiologic-pathologic correlation

Intrahepatic cholangiocarcinoma is the second most common primary hepatic tumor. Various risk factors have been reported for intrahepatic cholangiocarcinoma, and the radiologic and pathologic findings of this disease entity may differ depending on the underlying risk factors. Intrahepatic cholangiocarcinoma can be classified into three types on the basis of gross morphologic features: mass-forming (the most common), periductal infiltrating, and intraductal growth. At computed tomography (CT), mass-forming intrahepatic cholangiocarcinoma usually appears as a homogeneous low-attenuation mass with irregular peripheral enhancement and can be accompanied by capsular retraction, satellite nodules, and peripheral intrahepatic duct dilatation. Periductal infiltrating cholangiocarcinoma is characterized by growth along the dilated or narrowed bile duct without mass formation. At CT and magnetic resonance imaging, diffuse periductal thickening and increased enhancement can be seen with a dilated or irregularly narrowed intrahepatic duct. Intraductal cholangiocarcinoma may manifest with various imaging patterns, including diffuse and marked ductectasia either with or without a grossly visible papillary mass, an intraductal polypoid mass within localized ductal dilatation, intraductal castlike lesions within a mildly dilated duct, and a focal stricture-like lesion with mild proximal ductal dilatation. Awareness of the underlying risk factors and morphologic characteristics of intrahepatic cholangiocarcinoma is important for accurate diagnosis and for differentiation from other hepatic tumorous and nontumorous lesions.

Diagnostic imaging of carcinomas of the gallbladder and the bile ducts

Early diagnosis and accurate staging of carcinomas of the gallbladder and the bile ducts are helpful in improving the prognosis. Ultrasonography (US), a useful initial modality when exploring the background of jaundice or non-specific gastrointestinal complaints, sensitively reveals bile duct obstruction in particular. In unclear cases, or if US suggests a resectable biliary malignancy, computed tomography (CT), magnetic resonance imaging (MRI) with magnetic resonance cholangiography (MRC) and / or traditional cholangiography often provide additional information, and imaging-guided fine-needle biopsy or an endoscopic brush sample may verify the malignant nature of the tumor. Complementary modalities are usually needed for accurate staging, and traditional cholangiography is often performed for therapeutic purposes as well. Comparative studies of MRI with MRC and multidetector CT in biliary cancers would be welcome.

The cystic duct: normal anatomy and disease processes

The cystic duct can be depicted with a variety of imaging modalities but is optimally visualized with direct cholangiography or magnetic resonance cholangiopancreatography. Nevertheless, unrecognized anatomic variants of the cystic duct may cause confusion on imaging studies and complicate subsequent surgical, endoscopic, and percutaneous procedures. Primary entities involving the cystic duct include calculous disease, Mirizzi syndrome, cystic duct-duodenal fistula, biliary obstruction, neoplasia, and primary sclerosing cholangitis. The cystic duct may also be secondarily involved by adjacent malignant or inflammatory processes. Postoperative alterations are seen after liver transplantation or cholecystectomy when a portion of the cystic duct is left behind as a remnant. Recognized postoperative complications include retained cystic duct stones, cystic duct leakage, and malposition of T tubes in the remnant. Pitfalls encountered in cystic duct imaging include pseudocalculous defects from overlap of the cystic duct and common bile duct, underfilling of the cystic duct during direct cholangiography, and admixture defects at the cystic duct orifice. Pseudomass or pseudotumor defects may result from an impacted cystic duct stone or from a tortuous, redundant cystic duct. Familiarity with the imaging appearance of the normal cystic duct, its anatomic variants, and related disease processes facilitates accurate diagnosis and helps avoid misinterpretation.

New approach in diagnosis of bile duct disease with ultrasound and magnetic resonance imaging

Advances in technology have made possible the clinical application of magnetic resonance cholangiography, endoscopic, intra-operative and laparoscopic ultrasound in the study of the biliary tree, in addition to conventional magnetic resonance imaging and transabdominal ultrasound. The role of the conventional, as well as the newer techniques, in the diagnosis of bile duct disease and the limitations and pros and cons of each technique, will be the subject of the present discussion.