Involved people : Gilles Bertrand, Michel Couprie, Xavier Daragon. Associated students : Christophe Doublier, Xavier Rozé, Nicolas Sebestyen (4 th year ESIEE).
The magnetic resonance imagery (MRI) makes it possible to obtain three-dimensional images of the brain, which can then be segmented into its various parts (cortex, cerebellum, medulla...). The cerebral cortex has a particularly simple topological structure, on the other hand its geometry is complex: one can compare it with a (thick) sheet of paper ruffled, folded up on itself.
In several medical applications, it is necessary to extract with exactitude the cortical folds. For example in the processing of acute forms of epilepsy, requiring a surgical operation, the analysis of these folds makes it possible to the surgeon to prepare his operation.
We study an automatic procedure of extraction of the cortical folds starting from MRI data. We will privilege an approach based on the topological properties of the cortex: those being known and simple, they can provide indications for the ``reconstruction'' of the folds.
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Figure 19. (a): A cross-section extracted from a 3D MRI of the head. (b): An enlarged image showing some cortical folds.