Fig. 1.

The enantiomorphic normalization algorithm. A structural image and a matching lesion mask are aligned in the sagittal midline using rigid body coregistration to the opto-isometrically flipped version of the structural image. The mask is then flipped opto-isometrically and used to extract the signal within the precise region in the unaffected hemisphere that corresponds to the lesion on the other side. This is then used to replace the signal corresponding to the lesion. The resultant corrected image is then normalized using SPM2's standard spatial normalization routine.