1. An adaptation system ( 200 ) for adapting a deformable model comprising a plurality of model elements to an object of interest in an image data set, said system comprising: a selector ( 220 ) for selecting at least one image-driven model element from the plurality of model elements; and an adapter ( 230 ) for adapting the deformable model on the basis of optimizing a model energy of the deformable model, said model energy comprising an internal energy of the plurality of model elements and an external energy of the at least one image-driven model element, thereby adapting the deformable model.