thanks all for your attention!
I generate an atlas from subject’s T1 using freesurfer and its resolution is 256256256, then I use the 5ttgen and ACT to process subject’s T1 and DWI to generate tracts.
I want to get tracts belong to brain regions in the atlas, considering that the T1 and DWI are not in the same space, so I register the atlas to DWI :
flirt -in /Volumes/Elements/mrtransform/brain.nii.gz -ref /Volumes/Elements/mrtransform/bet_B0.nii.gz -omat /Volumes/Elements/mrtransform/T12DWI.mat transformconvert /Volumes/Elements/mrtransform/T12DWI.mat /Volumes/Elements/mrtransform/brain.nii.gz /Volumes/Elements/mrtransform/bet_B0.nii.gz flirt_import /Volumes/Elements/mrtransform/T12DWI.txt mrtransform /Volumes/Elements/mrtransform/MRN_006_hemisphere_7network.nii.gz -linear /Volumes/Elements/mrtransform/T12DWI.txt /Volumes/Elements/mrtransform/MRN_006_hemisphere_7network_inDWIspace.nii.gz -force
this is the registered atlas, background is bet b0:
this is the original atlas:
it seems that the registered atlas is bigger and the original one fit better? what could be the reason?