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Dear Bruce,
The other day I asked you about doing topology correction on my own segmentation(I have put my first e-mail and you response in the following so u can track easier). according to what you suggested, I have created a synthetic T1 volume based on my own segmentation. Now I wonder what to do exactly as the second step. Should I use "mris_fix_topology"?
I would be grateful if you could help me with that.
Best,
Maedeh
"Dear FreeSurfer experts, I know that FreeSurfer does segmentation, surface reconstruction and topology correction through its routine pipeline using "recon-all" . However, I have some T2w brain MR images and I have done the segmentation and extracted WM, GM, and CSF with my own algorithm. Now I need to remove back to back (i.e. a part of topology correction) which is caused in sulci due to the segmentation. In other word, after doing my segmentation, I wanna open the closed concavities in CSF that were open originally. Now I wanna know if I can do the topology correction using FreeSurfer while I have done the segmentation by myself? I would be grateful if you could help me with that. Best, Maedeh
Hi Maedeh
in principle you can, although it would be a lot easier if you just had a reasonable quality T1. If not, you will need to create all the files that recon-all expects to exist prior to the topology correction step (wm.mgz, norm.mgz, orig.mgz, ....). Maybe the easiest thing to do would be to use your gray/white/csf segmentation to create a synthetic T1 volume? Set all the wm voxels to 110, all the gray to 70 and all the csf to 20, or something like that?
cheers Bruce"