The present invention relates to an apparatus for detecting deformation of a body part. It is described to provide (210) a magnetic resonance image of a patients body part, the magnetic resonance image of the body part comprising structural information of the body part, wherein the structural information comprises large scale structural information. A model of the body part is provided (220), the model of the body part comprising structural information of the body part, wherein the structural information comprises large scale structural information. At least one transformation is applied (230) to the model of the body part and/or to the magnetic resonance image of the body part, wherein the at least one transformation comprises transformation on the basis of at least some of the large scale structural information. A fit is determined (240) between the model of the body part and the magnetic resonance image of the body part comprising application of the at least one transformation. A deviation is determined (250) between the model of the body part and the magnetic resonance image of the body part on the basis of the structural information in the magnetic resonance image and the structural information in the model of the body part. Information relating to the deviation is provided (260).Linvention concerne un appareil servant à détecter une déformation dune partie du corps. La présente invention consiste à fournir une image de résonance magnétique (210) dune partie du corps dun patient, cette image de résonance magnétique comprenant des informations structurelles de la partie du corps, ces informations structurelles comprenant des informations structurelles à grande échelle. Linvention consiste également à fournir un modèle de la partie du corps (220), ce modèle comprenant des informations structurelles de la partie du corps, ces informations structurelles comprenant des informations structurelles à grande échelle. Au moins une transformation est appliquée (230) au mo
