Hi Ri

There are some undocumented features in mri_distance_transform that let you specify a surface (-wsurf <white surface>) and/or an aseg (-aseg) and it will compute what I called an “interior distance transform”. That is, a distance transform constrained to the interior of the white matter. I wrote it for some stuff I was messing around with like 10 years ago so don’t remember it terribly well, but it did work once upon a time 😊. You might need to look at the code to sort out how it works.

Cheers Bruce

From: freesurfer-bounces@nmr.mgh.harvard.edu freesurfer-bounces@nmr.mgh.harvard.edu On Behalf Of Ritobrato Datta Sent: Thursday, April 15, 2021 11:44 AM To: freesurfer@nmr.mgh.harvard.edu Subject: [Freesurfer] euclidian distance masks using free surfer tools

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Hello,

I want to create 3-dimensional euclidean / geodesic distance masks that are essentially concentric rings of 3 mm thickness in the white matter that start from the ventricle toward the cortex. Is there an easy way to do that using freesurfer tools ? I have attached a figure from an article where this approach has been used.

[cid:image002.png@01D732AB.6F348BB0]

Please let me know.

Thanks

Ri