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?