Hi Francesco, Could you maybe send a snapshot of the brainmask and wm volumes where you are seeing this?

If you deleted any voxels on the wm mask then they should be a value of 1.

You might want to look at the ?h.orig.nofix surfaces to see if that area in question looks better (or at least different). Ultimately the position of the wm surface is what is important, not the presence or absence of wm voxels (in the wm.mgz) which basically just initialize the wm surfaces. -Louis

On Mon, 9 Sep 2013, Francesco Siciliano wrote:

Hi, I've noticed that occasionally when I manually edit recons, the white matter surface will be drawn to include a portion of the volume where no white matter pixels are present. Therefore, when I go to correct the incorrectly drawn surface, there are no pixels to delete under the white matter mask. It is almost as if I have deleted the pixels already yet I have not and the white matter surface is still drawn to include an area where there are no white matter pixels. Why could this be happening? Does it matter as long as there are no pixels in the incorrect area?

Thank you,

Francesco

Francesco Siciliano, B.A. Research Assistant Department of Child and Adolescent Psychiatry The New York State Psychiatric Institute Columbia University 1051 Riverside Drive, Unit 74 New York, NY 10032 (212) 543-6155