Hi Cyril
Now it works! Thanks a lot?
But there are two problems:
1. How to get the valid number of voxels!
I have tried it with the following function from John:
V = spm_vol(spm_get(1,'*c1*.img'));
vol = 0;
for i=1:V.dim(3),
img = spm_slice_vol(V,spm_matrix([0 0 i]),V.dim(1:2),0);
vol = vol + sum(img(:));
end;
fprintf('%g voxels, %g litres\n', vol, vol*det(V.mat(1:3,1:3))*1e-6);
2. The results seem to be invalid.
e.g. 0.4954 * 327888 voxels (1mm*1mm*1mm) = 162435 and this is equal to
0.162 l
I investigate the brains of AD patients and these brains are degenerated but
only
0.162 l GM seems to be a too small volume in order to be a valid measure of
GM volume.
If I divide the number of voxels bei the value for the modulation then the
volume seems
to be more plausible:
327888 voxels (1mm*1mm*1mm) / 0.4954 = 0.662 l
The corresponding result from the script of John is:
0.563 litre
What do you think?
Thanks a lot in advance
Best regards
Juergen
> -----Ursprüngliche Nachricht-----
> Von: Cyril Pernet [mailto:[log in to unmask]]
> Gesendet: Donnerstag, 4. August 2005 07:55
> An: Jürgen Hänggi
> Betreff: Re: AW:Re: [SPM] GM/WM/CSF volume computation in SPM5b]
>
> Hi Jürgen
>
> well it's not an error ...
>
> > Hi Cyril
> >
> > Thanks a lot for your advice.
> > But the function:
> >
> > spm_global(spm_vol('*.img'))
> >
> > does not work and I have no experience in M-file programing.
>
> to use that go into the directory where your image(s) is
> (are) strored and type the function with the name like
> spm_global(spm_vol('mwc1_jurgen*.img')) ;-) everything should be ok
>
> best
> - cyril
>
>
>
>
>
>
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