A method for automatically segmenting a liver in digital medical images includes providing a 3-dimensional (3D) digital image I and a set of N training shapes {φi}i=1, . . . , N for a liver trained from a set of manually segmented images, selecting a seed point to initialize the segmentation, representing a level set function φα(θx+h) of a liver boundary Γ in the image as φ α  ( x ) = φ 0 + ∑ i = 1 n  α i  V i  ( x ) ,  where  φ 0  ( x ) = 1 N  ∑ i = 1 N  φ i  ( x ) is a mean shape, {Vi(x)}i=1, . . . , n are eigenmodes where n