Results

The effect of the transformations found by the automatic registration procedure are illustrated at figure . The cortical surface and ventricular systems from the CBA appear in grey, the structures from the MR image in black. The grid allows us to visualize the deformations.

  

Figure 7.6: Effect of the registration transformations. Left: Affine transformation. Right: Additional second degree components. Up: Axial cut Down: Sagital cut.

The ultimate aim of computerized atlases is to achieve a 3D representation of all identifiable anatomical structures in the individual brain. As shown in figure , this objective is well reached by the present work which allows to delineate unambiguously the sylvian fissure (sl), the superior frontal (ssf), the precentral (spc), the central (sc) and the parieto-occipital (spo) sulci. As clearly seen on the top slice, the template for the left superior frontal sulcus does not match with the one of the subject despite the perfect matching of that sulcus on the contralateral hemisphere. Inter-hemispheric variations in the topography of the sulcal patterns represents an intrinsic limitation in this approach.

  

Figure 7.7: Some CBA structures overlaid over the MRI: Cortical surface, ventricular system and a few sulci.