AFNI Message Board

Dear AFNI users-

We are very pleased to announce that the new AFNI Message Board framework is up! Please join us at:

https://discuss.afni.nimh.nih.gov

Existing user accounts have been migrated, so returning users can login by requesting a password reset. New users can create accounts, as well, through a standard account creation process. Please note that these setup emails might initially go to spam folders (esp. for NIH users!), so please check those locations in the beginning.

The current Message Board discussion threads have been migrated to the new framework. The current Message Board will remain visible, but read-only, for a little while.

Sincerely, AFNI HQ

History of AFNI updates  

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November 29, 2022 10:12AM
Hi, Robin-

That EPI has a fair amount of brightness inhomogeneity. See how a lot of sulcal/gyral structures appear washed out and hard to see by the brightness around the edge.

To help deal with that, we created a new local unifizer that seems to really help with EPI-anatomical alignment of human FMRI datasets (*animal datasets have more external features, so still working on some special cases there, separately but relatedly). Anyways, can you try adding option this to your AP command:
-align_unifize_epi local \
(NB: this is *not* in place of anything there, but added separately.) Please let us know if that improves EPI-anatomical alignment.

Note: deobliquing the anat and EPI ahead of time makes a lot of sense. In your first chunk of code, this does deobliquing of the anatomical while preserving the location of the (x,y,z)=(0,0,0) part of the dataset:
3dcopy T1_$subject.nii tmp
3drefit -oblique_recenter tmp+orig
3drefit -deoblique tmp+orig 
3dcopy tmp+orig T1_do_$subject.nii
The subsequent 3dCM command then translates the dataset spatially so that its center-of-mass will sit at (x,y,z)=(0,0,0). Note that that might leave the EPI dataset behind, and relatively far away, because its coordinates were not reset---that appears to be the case, from the "initial overlap" images. What I might do instead would be to run, *assuming your EPI and anatomical were pretty well aligned to start*:
# deoblique the T1w volume, keeping coord origin
3dcopy T1_$subject.nii tmp
3drefit -oblique_recenter tmp+orig
3drefit -deoblique tmp+orig 
3dcopy tmp+orig T1_do_$subject.nii

# deoblique the EPI volume, keeping coord origin
3dcopy EPI_$subject.nii tmp
3drefit -oblique_recenter tmp+orig
3drefit -deoblique tmp+orig 
3dcopy tmp+orig EPI_do_$subject.nii

# translate the anatomical to have its CM match the template's CM,
# ... and bring along the EPI as a "child" dataset
@Align_Centers \
   -cm \
   -base MNI152_2009_template_SSW.nii.gz \
   -dset T1_do_$subject.nii \
   -child EPI_do_$subject.nii

# check anatomical-template overlap
@djunct_overlap_check \
    -ulay T1_do_${subject}_shft+orig \
    -olay MNI152_2009_template_SSW.nii.gz \
    -prefix img_olap_t1w_template

# check EPI-anatomical overlap
@djunct_overlap_check \
    -ulay T1_do_${subject}_shft+orig \
    -olay EPI_do_${subject}_shft+orig \
    -prefix img_olap_epi_t1w
... and see how those overlap images look? Can you try that for one subject?

Then, you would run SSW on the T1_do_${subject}_shft+orig, and use those results and the EPI_do_${subject}_shft+orig dset in your AP command.

--pt
Subject Author Posted

Poor aligment using scripts that have worked before Attachments

Robin November 29, 2022 09:31AM

Re: Poor aligment using scripts that have worked before Attachments

Robin November 29, 2022 09:32AM

Re: Poor aligment using scripts that have worked before

ptaylor November 29, 2022 10:12AM

Re: Poor aligment using scripts that have worked before Attachments

Robin November 30, 2022 07:29AM

Re: Poor aligment using scripts that have worked before

ptaylor November 30, 2022 08:15AM