top | Longitudinal Tutorial

Making white matter edits

For the longitudinal stream, it is recommended that you make wm.mgz edits to the base. This is because even though the long transfers manual wm edits from the cross, it still takes the surfaces from the base, and if the base surfaces did not improve, neither will the long. The only way to make corrections to the base surfaces themselves is to edit wm.mgz on the base. Therefore, making wm.mgz right on the base can save you a lot of time. Of course it is best to edit all stages (all cross time points and base), but often it is sufficient to edit only the base. Were you able to find the area that needs intervention? Here is what we found. You can see below on the brainmask.mgz (left) that the pial surface is cutting through the wm. If you toggle to the wm.mgz (right), you can see that there are a few wm voxels missing.

This happens at the tip of the lh temporal lobe within several slices (coronal slice 166 and 169).
0185bm_166_before.jpg 0185bm_169_before.jpg

Add wm voxels to connect the wm together in all the slices that need it. Here is what we did.
0185wm_166_after.jpg 0185wm_169_after.jpg

After you are satisfied with your edits, save the edited volume and rerun the base.

Don't run the recon-all commands on this page

It will take hours and has already been done for you.

recon-all -base OAS2_0185 -autorecon2-wm -autorecon3

After that is done, check the surfaces on base using Freeview (or tkmedit for older version of Freeview).

freeview -v OAS2_0185_fixed/mri/wm.mgz \
            OAS2_0185_fixed/mri/brainmask.mgz \
         -f OAS2_0185_fixed/surf/lh.pial:edgecolor=red \
            OAS2_0185_fixed/surf/rh.pial:edgecolor=red \
            OAS2_0185_fixed/surf/lh.white:edgecolor=blue \

This is what it should look like now in slice 166.

When the surfaces are all corrected, you would recreate the long (make sure you remove the long directories before the rerun - or at the very least, remove the wm.mgz files in all the mri sub-directories of the long runs).

recon-all -long OAS2_0185_MR1 OAS2_0185 -all

recon-all -long OAS2_0185_MR2 OAS2_0185 -all

Inspect your output:

freeview -v OAS2_0185_MR1.long.OAS2_0185_fixed/mri/wm.mgz \
            OAS2_0185_MR1.long.OAS2_0185_fixed/mri/brainmask.mgz \
         -f OAS2_0185_MR1.long.OAS2_0185_fixed/surf/lh.pial:edgecolor=red \
            OAS2_0185_MR1.long.OAS2_0185_fixed/surf/rh.pial:edgecolor=red \
            OAS2_0185_MR1.long.OAS2_0185_fixed/surf/lh.white:edgecolor=blue \

freeview -v OAS2_0185_MR2.long.OAS2_0185_fixed/mri/wm.mgz \
            OAS2_0185_MR2.long.OAS2_0185_fixed/mri/brainmask.mgz \
         -f OAS2_0185_MR2.long.OAS2_0185_fixed/surf/lh.pial:edgecolor=red \
            OAS2_0185_MR2.long.OAS2_0185_fixed/surf/rh.pial:edgecolor=red \
            OAS2_0185_MR2.long.OAS2_0185_fixed/surf/lh.white:edgecolor=blue \

See here that the improved surfaces in the base also correct the surfaces in the long. Compare MR1.long slice 163 in the before (left) and after (right) images below.
0185_long1_163_before.jpg 0185_long1_163_after.jpg

The same improvement should have occurred with MR2.long.

Fstutorial/LongWMEdits_freeview (last edited 2018-03-05 11:55:56 by LeahMorgan)