I have to merge the T1 MRI images of a patient with its white matter tract of corticospinal tract for use in neurosurgery navigator. How can I do with MRIcroGL?
Can you help me?

I need to use freesurfer brain_anat.nii T1 and path.pd.nii (CST lh WM tract ) . It is necessary to merge the two-volume images in one and after to transform it in dicom

I would use FSL, AFNI or SPM to coregister your two images (SPM's segmentation and FSL's FAST might also be useful). You can then use MRIcroGL to view the aligned images using one as the overlay for the other. The Scripting/Templates menu provides examples.