Fig. 1.

Examples of probabilistic atlases. (a) An average intensity atlas computed from co-registered MRI data (b) A tissue-type probability atlas computed from co-registered tissue fraction maps produced from MRI. Each voxel was partitioned into grey matter, white matter, or CSF components in the original volumes (shown here in green, blue, or red, respectively). The values are transformed into the common atlas space, then used to compute the likelihood of each voxel in the atlas space containing the different tissue types. (c) A probabilistic structure atlas computed from co-registered cortical structure delineations. The delineations (see Table 1 for color index) are mapped into the atlas space, then used to create density maps for each structure in the volume. The figure shows a maximum likelihood labeling generated from a probabilistic structure atlas.