Is there a way to re-do the generation of the ribbon but generate it
with a smaller voxel size? I've already had success resampling the
T1.mgz to 0.25mm and using it as a template for mri_surf2vol with --
mkmask and --fillribbon, but the problem is that only projects out
from the vertices, so the resulting ribbon is sparse and thready, and
doesn't fill the whole cortical ribbon. (Likewise the ?h.ribbon.mgz
file seems to be missing a lot of voxels in its interior.)
Ideally what I want is to be able to overlay the surfaces onto a
volume of my chosen resolution, and then fill the voxels between the
surface. I've been looking at matlab code, and found this program:
http://tinyurl.com/2bbyap
surface2volume.m which allegedly does what I want, but it doesn't
actually seem to work right when I try it: I get only a few scattered
voxels filled.
Does anyone have any idea of how to do this? Any help is greatly
appreciated!
On May 3, 2007, at 10:31 AM, Bruce Fischl wrote:
Hi David,
we do generate such a thing called ?h.ribbon.mgz, but note that
once you go back into the volume the topology is no longer preserved.
cheers,
Bruce
On Thu, 3 May 2007, David Perlman wrote:
I'm new to freesurfer, so I'm hoping this question isn't too
obvious. I've searched the mailing list archives and the wiki but
haven't found any leads.
I'm wondering if there's a way to generate a volume representation
of the cortical sheet, based on the data from the white surface
and the pial surface, so that the sheet will be guaranteed to have
good topology, as well as retaining the proper thickness at each
point? It seems like all the information for this is there
already since we have the two surfaces, but I don't know how to go
about figuring out how to convert it into volume data.
Here's a small image that might help give an idea of what I need:
http://brainimaging.waisman.wisc.edu/~perlman/corticalsheet.png
In case you're curious, the reason I want this is because we're
trying to test the novel method for cortical thickness measurement
given in "Three-Dimensional Mapping of Cortical Thickness Using
Laplace's Equation", Jones, Buchbinder and Aharon, Human Brain
Mapping 11:12-32(2000).
--
-dave----------------------------------------------------------------
After all, it is not *that* inexpressible.
-H.H. The Dalai Lama
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-dave----------------------------------------------------------------
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on a higher level as friends. -Göthe
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