This process uses the command mri_fill to create a binarized volume. The input is the mri/wm volume and the output is the mri/filled volume. First, the cutting planes are determined to seperate the hemispheres from each other and the pons. Then a seed point is located and used to fill each hemisphere. The rh will be filled with a value of 255, and the lh with a value of 127.
Occasionnally, manual intervention is required to define the cutting planes and seed points. To do so, follow these steps:
1.Open the subject's wm volume up in tkmedit.
tkmedit subject_name wm
2.View the MNI talairach coordinates.
3.Select the Corpus Callosum point, on the mid-posterior portion of it. Example:
attachment:CCcor.jpg attachment:CChor.jpg attachment:CCsag.jpg
4.Copy the MNI coordinates to the command line for either recon-all -cc-xyz .... or in mri_fill -C ....
5.Do this for all of the other cutting plane points and seed points. Examples follow:
attachment:Pcor.jpg attachment:Phor.jpg attachment:Psag.jpg
attachment:RHcor.jpg attachment:RHhor.jpg attachment:RHsag.jpg
attachment:LHcor.jpg attachment:LHhor.jpg attachment:LHsag.jpg