Hi Rosie,
Are you trying to combine all volume files (.nii.gz) into one single volume by stacking all frames? Maybe you should use Freesurfer mri_concat instead of mrcalc?
Here are the help pages for mri_concat and mri_vol2surf:
https://surfer.nmr.mgh.harvard.edu/fswiki/mri_concat https://surfer.nmr.mgh.harvard.edu/fswiki/mri_vol2surf
Best,
Yujing
From: freesurfer-bounces@nmr.mgh.harvard.edu freesurfer-bounces@nmr.mgh.harvard.edu On Behalf Of Rosie Sent: Thursday, February 29, 2024 10:55 PM To: freesurfer@nmr.mgh.harvard.edu Subject: [Freesurfer] Assistance Request: Issue with Merging .mgh Files in Ubuntu18
External Email - Use Caution Dear Support Team,
I'm reaching out for assistance with merging two .mgh files.
As I try to generate a surface mapping for all subjects, I merged all volume files (.nii.gz) by mrcalc. So I get a volume file whose voxel value represents the number of valid subjects. And then I convert it to .mgh using mri_vol2surf. But the value of each voxel seems to be thrown out. Because I found the max value of .mgh is not the same as .nii file.
I guess I should merge files of all subject in mgh format to maintain the number of valid subjects, but it seems to be a volume encoded surface file format. So I don't know how to merge them.
I'm working on Ubuntu18.
I would be very grateful for your assistance.
Best, Rosie
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