A procedure for image segmentation on three-dimensional (3D) medical images, and a system, apparatus, and computer program that operate in accordance with the procedure. The procedure includes generating a projection including an anatomic structure, tracing a curve corresponding to the anatomic structure, extracting a curved volume of interest based on the curve and the projection, and extracting a segmentation of the anatomic structure. Also provided is a procedure for aligning anatomic structures in images, and a system, apparatus, and computer program that operate in accordance with the procedure. The procedure includes determining part of a biliary system in a first image, determining part of a hepatic portal vein or a hepatic artery in a second image, determining a gallbladder in the images, determining a cost function, and aligning the biliary system and the hepatic portal vein or hepatic artery by maximizing the cost function.