1. A method of segmenting a three-dimensional structure, which is contained in an object, from at least one two-dimensional image (I 1, I 2 ) which represents a slice of the object, which method utilizes a deformable model (M) whose surface is formed by a network of meshes which interconnect network points on the surface of the model, and which method includes the steps of: a) determining the meshes (T 3, T 4 ) which intersect the image (I 1, I 2 ), b) searching, for each mesh determined in the step a), a respective structure point (x is ), situated on the surface of the structure, along a search line (n i ) which traverses the mesh and extends in the image, c) calculating a new the network points (x im ) of the model (M) on the basis of the structure points (x is ) found, and d) repeating the steps a) to c) a number of times on the basis of the newly calculated network points.