Figure 1 Imaging findings in a patient with alveolar echinococcosis. (A) Image shows axial unenhanced computed tomography (CT) slice through the porta hepatis. An irregular hypodense mass is seen in the porta hepatis extending into the right lobe of the liver. Arrow shows thick calcifications of the anterior rim of the lesion. (B) Arterial phase coronal CT slide demonstrates the localization of the mass and its relation to the surrounding structures. Arrow: circumferential encasement of the hepatic artery is demonstrated, as well as the portal vein. The mass itself remains hypovascular to the adjacent hepatic tissue. Cystic components of the lesion in the 8th segment of the liver are more conspicuous after contrast agent application. (C) Portal venous phase coronal CT slice shows no enhancement of the mass. Arrow: slight intrahepatic bile duct dilatation is observed in the 5th segment. (D) Magnetic resonance cholangiopancreatography coronal maximum intensity projection reconstruction demonstrates multiple short segment stenoses of the common and right hepatic bile duct (indicated by arrow). (E, F) T1-weighted and T2-weighted coronal slices demonstrate the hypointense signal of the main lesion bulk in the porta hepatis (indicated by arrow).