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Merging sulcal segments with AIMS results in inconsistent features

Posted: Thu Mar 23, 2017 9:10 pm
by ruslana
Hello,

I am trying to merge a few nodes in cortical graph with AIMS. Here is the procedure I am following:
1. merge mesh from the segments (using aims.SurfaceManip.meshMerge)
2. assign the merged mesh to one of the nodes (aims.GraphManip.storeAims) and remove all other nodes (graph.removeVertex)
3. run 'Compute Cortical Fold Graph Upgrade From Old' process in order to recalculate morphometric attributes for the merged node from the new, merged, mesh (with the 'compute_fold_meshes' flag set to False).

The 2 first steps seem to work, but the 3rd one did not update the merged node as expected. Looking at the merged node and comparing the values before and after the procedure run, I've seen that:
- some attributes were not updated, i. e. the same value before and after the merging (refsize or refmaxdepth, for example),
- some attributes got higher value, but new value is significantly lower then expected, i.e. significantly lower then a sum of, or even then a single max value across the merged nodes (white_surface_area, for example), and
- some attributes value even went down (refsurface_area, for example)

Is there anything wrong in the procedure I am using? Am I missing anything? Or may be there is a different - better - way to properly merge cortical segments? Any help would be highly appreciated.

Regards,
Ruslana.

Re: Merging sulcal segments with AIMS results in inconsistent features

Posted: Mon Mar 27, 2017 11:32 am
by riviere
Hi,
I think the problem is due to the fact that you have changed only the meshes in the graph, but most attributes are computed from the buckets (voxels lists) in the nodes, which you haven't changed. For me it doesn't explain everything you report, but maybe the mismatch between voxels lists and meshes could have strange effects.
Denis

Re: Merging sulcal segments with AIMS results in inconsistent features

Posted: Wed Mar 29, 2017 4:59 pm
by ruslana
Denis,
Thanks a lot for your reply. It works now.
Regards,
Ruslana.