Hello,

I have two issues, currently.

First, I was wondering if it would be possible to create separate FSAverage
brains for different subject groups. I am working with healthy seniors and
various stages of Alzheimer's disease, so doing so would be very helpful
from the perspective of not conflating the differences in neuroanatomy
between the these groups. One idea we had was to create separate HOME
directories for each group, but we wanted to know if there was an easier
way. I can't find anything in the interwebs about this.

Second, I utilize some ROIs that are not specified by FS (such as secondary
somatosensory cortex and anterior vs. posterior insula). My means of
getting around this was to use FSAverage and tksurfer to hand-draw them,
save them as '.label' files, map them to individual subjects, and export
them to AFNI since much of our correlation analysis is done on that
platform. However, I've noticed that when I view these hand-drawn ROIs in
AFNI they only show up at the border of the gray and white matter, rather
than filling the entirety of the gray matter. Note that this problem does
not occur for ROIs in the look up table (like the caudal ACC). Exporting
these to AFNI gives you a nice ROI that fills all the gray matter in the
defined region.

*Code I'm using*:
For the latter problem, what I first use is mri_label2label to map the
fsaverage-based ROI onto individual subjects, for example with the left
anterior insula, before using mri_label2vol:
*mri_label2label --srclabel lh.aIns.label --srcsubject fsaverage --trglabel
lh.aIns.label --trgsubject [subj] --regmethod surface --hemi lh*

*mri_label2vol --label ../label/lh.aIns.label --regheader aparc+aseg.mgz
--o gmroi_volume.nii.gz --temp orig/001.mgz*


Then I copy the new volume file to their AFNI folder, rename it, and run my
correlation analysis on them.

Note, that for those ROIs that are in the look up table (those parcellated
by freesurfer) I simply use mri_label2vol before extracting them using
3dcalc (for example, the caudal anterior cingulate)...
*mri_label2vol --seg aparc+aseg.mgz --regheader aparc+aseg.mgz --o
gmroi_volume.nii.gz --temp orig/001.mgz*

*3dcalc -a gmroi_volume.nii.gz -expr 'equals(a,1002)' -prefix
ROI_FS_lh.caudalACC.nii.gz*



tl:dr
Is it possible to "easily" create multiple FSAverages based on selected
subjects (in my case, subject groups separated by disease state)?

and

Does anyone have any advice on how to get hand-drawn surface-based ROIs
from Freesurfer's tksurfer into AFNI that full cover the entirety of the
gray matter?


Cheers and thanks!
-- 
Paul Beach
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