1. A method of detecting blood vessel bifurcations in digital medical images, comprising the steps of: providing a binary segmented 3D image volume having a segmented blood vessel; inflating a sphere from a first center point inside a segmented blood vessel until a surface of said sphere intersects a surface of said blood vessel; searching within the inflated sphere for a second center point that has a sphere intersecting a surface of said blood with a maximum radius; assigning all voxels of said maximal radius sphere to a root node of a shape-tree; increasing the radius of said maximal radius sphere, and computing a voxel difference set with respect to the previous maximal radius sphere; computing one or more connected components C m in the voxel difference set; assigning voxels of each connected components to a different child node of said shape tree, and connecting each child node with said root node; and calculating features from said shape tree for training a classifier to detect blood vessel bifurcations.