W551 disease believed to increase the risk of cholangiocarcinoma [3]. Sclerosing cholangitis often presents with clinical features of biliary obstruction, such as jaundice and pruritus, but usually in the absence of signs of infection. Primary sclerosing cholangitis tends to involve the intrahepatic bile ducts to a greater extent than the extrahepatic ducts. Approximately 15% of patients with primary sclerosing cholangitis develop cholangiocarcinoma [4]. Cholangiocarcinoma is less common than other hepatic and cholecystic malignancies, representing approximately 1% of all malignancies. Most cholangiocarcinomas are adenocarcinomas [5]. Most patients with cholangiocarcinoma present between the sixth and seventh decades of life; however, patients with primary sclerosing cholangitis can develop cholangiocarcinoma at a younger age [5]. The extrahepatic biliary ducts are affected more commonly than the intrahepatic ducts [5]. An increased serum CA19-9 level can also be observed in patients with cholangiocarcinoma, whereas elevated α-fetoprotein levels are associated with hepatocellular carcinoma rather than cholangiocarcinoma [5]. Biliary obstruction is most commonly due to choledocholithiasis. Obstruction may also be a consequence of biliary strictures, malignancy, iatrogenic disease, and parasitic disease [6]. Biliary obstruction precipitates acute suppurative cholangitis by causing hepatovenous reflux and subsequent bacteremia [7]. The organisms most commonly associated with acute suppurative cholangitis include Escherichia coli, Klebsiella species, Proteus species, Bacteroides species, and Pseudomonas aeruginosa [8]. The classic clinical presentation is of right upper quadrant pain, fever, and jaundice (Charcot triad), sometimes with hypotension and altered consciousness (Reynolds pentad) [6, 9]. Acute suppurative cholangitis may lead Imaging of Biliary Tract Disease