Disease of the Gallbladder and Biliary Tree

Cross-sectional imaging modalities including ultrasound (US), magnetic resonance (MR) imaging, and computed tomography (CT) play a critical role in the diagnosis of gallbladder and biliary disease. Biliary imaging for evaluation of obstructive jaundice seeks to diagnose the level of obstruction and its cause. The identification of dilated bile ducts necessitates evaluation for strictures or filling defects, which is best performed with thin-section CT or T2-weighted MR cholangiography. Choledocholithiasis is the most common cause of biliary obstruction, and modern thin-section three-dimensional MR cholangiography is highly sensitive and specific for the detection of stones. Identification of bile duct wall thickening raises concern for cholangitis or malignancy. Primary sclerosing cholangitis and secondary sclerosing cholangitis such as recurrent pyogenic cholangitis and IgG4-related sclerosing disease can develop chronic progressive cholestatic liver disease characterized by inflammation, fibrosis, and stricture of the bile ducts. Familiarity with the typical clinical and radiologic appearances of various etiologies of cholangiopathies and biliary malignancies is also important for accurate image interpretation. In order to detect and characterize diseases of the gallbladder appropriately, knowledge of congenital variants and anomalies of the gallbladder anatomy is essential. Understanding the pathogenesis responsible for gallstone formation and resultant imaging features will be outlined. Recognizing mechanisms leading to acute and chronic inflammatory scenarios of the gallbladder may influence the decision on appropriate treatment. Differentiating inflammatory gallbladder disease from gallbladder neoplasms can be challenging in early stages; recognizing imaging features which raise the suspicion for potential underlying neoplasms is essential in guiding potential treatment options.