SACHA extracts the hippocampus froma native scan according to
the protocol described in Chupin et al. [52–54]. The extraction
includes the fimbria, alveus, dentate gyrus, cornu ammonis, whereas
the subiculum is excluded. The SACHA software relies on region
deformation, introducing a competition between the hippocampus
and the amygdala. It gives the volume of both regions, but in the
current study we only took hippocampal volumes into account. First,
an extraction of a bounding box is done from probabilistic atlases.
The bounding box is defined around the amygdalo-hippocampal
complex. A conditional pruning gives the initial objects composed of
the region with maximal probability in each probability map. These
two initial objects constitute the starting point of the deformation
process. During the deformation, the algorithm automatically
aggregates voxels and converges to the segmentation of the
hippocampus and amygdala structure