Hi Prad - That part of the corpus callosum belongs neither to the left nor to the right hemi, it connects the two. So any split would be arbitrary. You could write a script that finds if a voxel is closer to the left or the right hemi for example.

Best,
a.y

From: freesurfer-bounces@nmr.mgh.harvard.edu [freesurfer-bounces@nmr.mgh.harvard.edu] on behalf of Bharadwaj, Pradyumna - (prad) [prad@email.arizona.edu]
Sent: Wednesday, January 18, 2017 12:48 PM
To: Freesurfer support list
Subject: Re: [Freesurfer] WM lobes and Corpus Callosum

Hello Anastasia,


Thank you for your reply!


I had created the 4 WM lobes  for each hemisphere to extract regional volumes for white matter lesions in each lobe.


As some of our participants have WML in the corpus callosum very close to the midline, they are not included in the WM lobes created earlier.


Do I need to manually edit the labels for the parts of the corpus callosum between the hemispheres to have them be included in one of the lobes  ?


Or is there some alternate way to split the CC in aseg.mgz along the hemispheric midline and assign its parts to the WM in each hemisphere ?



Best,

-Prad





From: freesurfer-bounces@nmr.mgh.harvard.edu <freesurfer-bounces@nmr.mgh.harvard.edu> on behalf of Yendiki, Anastasia <AYENDIKI@mgh.harvard.edu>
Sent: Tuesday, January 17, 2017 5:05 PM
To: Freesurfer support list
Subject: Re: [Freesurfer] WM lobes and Corpus Callosum
 
Hi Prad - mri_aparc2aseg assigns WM voxels to the nearest cortical region from the cortical parcellation. Which cortical region would you want to assign the corpus callosum to? What's labeled as corpus callosum in the aseg is the part of the corpus callosum between the 2 hemis.

Best,
a.y

From: freesurfer-bounces@nmr.mgh.harvard.edu [freesurfer-bounces@nmr.mgh.harvard.edu] on behalf of Bharadwaj, Pradyumna - (prad) [prad@email.arizona.edu]
Sent: Tuesday, January 17, 2017 5:37 PM
To: freesurfer@nmr.mgh.harvard.edu
Subject: [Freesurfer] WM lobes and Corpus Callosum

Hi,


I've been trying to create WM lobes using the following steps:


1) mri_annotation2label --lobesStrict

2) Outputting the labels from step 1, & creating a simpler annotation without limbic and insular lobes

3) Labeling the WM using mri_aparc2aseg (mri_aparc2aseg --s MySub --annot Step2AnnotationFile --labelwm --hypo-as-wm --wmpar-dmax 20 --rip-unknown


However, as the corpus callosum is not labelled as wm, it is not included in any WM lobe. 


Is there any workaround to assigning the corpus callosum to the different WM lobes or do I have to manually edit aseg.mgz to change the corpus callosum's value to match that of WM ?



Thanks,

-Prad