Statistical analysis of normal and abnormal dissymmetry in volumetric medical images

Presents a general method to study the dissymmetry of anatomical structures such as the human brain. The authors´ method relies on the estimate of 3D dissymmetry fields, the use of 3D vector field operators, and T² statistics to compute significance maps. They also present a fully automated implementation of this method which relies mainly on the intensive use of a 3D non-rigid inter-patient matching tool. Such a tool is applied successively between the images and their symmetric versions with respect to an arbitrary plane, both to realign the images with respect to the mid-plane of the subject and to compute a dense 3D dissymmetry map. Inter-patient matching is also used to fuse the data of a population of subjects. The authors then describe three main application fields: the study of the normal dissymmetry within a given population, the comparison of the dissymmetry between two populations, and the detection of the significant abnormal dissymmetries of a patient with respect to a reference population. Finally, the authors present preliminary results illustrating these three applications for the case of the human brain