Dear SPM Experts,
Using SPM2, after I segment the MPR image of the "wxS01mpr.img" file, I saw
the new file of "mwxS01mpr.img" with segmented images as gray matter, white
matter, and CSF.
Could anybody tell me what is the "mwxS01mpr.img" and what is "m" stands
for?
I closely look at both wxS01mpr.img and mwxS01mpr.img images, but both
images look the same.
Geon-Ho
----- Original Message -----
From: "Jesper Andersson" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, October 08, 2003 1:32 AM
Subject: Re: reslice slize
> Hi Jahng,
>
>
> > I acquired 3D T1 MPR image with 1x1x1.5(thickness) mm^3 of spatial
> > resolution and DTI data with 2.4x2.4x5 mm^3.
> > What is the best voxel size during writing the normalized T1 MPR images,
> > which is normalized to SPM T1 template?
> > I think I can choose one of 2x2x2 or 1.5x1.5x1.5 voxel size. I will
segment
> > the normalized T1 MPR images and apply to DTI data to mask out CSF in
DTI
> > data.
>
> I am not sure there is a conclusive answer to this question. Let me see if
I
> get you right. You want to spatailly normalise your T1 and DTI data,
segment
> the T1 data and used the CSF segment to mask out CSF from the DTI image in
> normalised space?
>
> There are of course practical considerations (such as larger matrices
taking
> more disc space) but I think on the whole that the segementation benefits
from
> keeping the high resolution. Around the ventricles one sometimes see
tissue
> being misclassified as gray matter. This is because a voxel with a mixture
of
> CSF and white matter will have an intensity similar to that of a gray
matter
> voxel. The higher resolution you have your data in, the fewer voxels will
there
> be with a mixture of tissue types.
>
> I would say that either choice (2 or 1.5) would do quite fine.
>
> Remember to coregister your DT map to your T1 image and select it as other
when
> spatially normalising.
>
> Good luck Jesper
>
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