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Hello All,
I am running into an odd problem when attempting to calculate volumes of
masked ROI's in my VBM data. What I am trying to accomplish is a correlation
between two different ROI's in my VBM data.

Here's what I have done:

1) created an sphere ROI mask with a radius of 5 mm in DLPFC using the
WFU_pickatlas util.
2) applied the mask using spm_mask to my smoothed and modulated vbm data.
This gives me m* files.
3) use the script below that was provided on this list-serve to calculate
volumes

>function gl = get_integrals(P)
>% Integrate the values in an image.
>if nargin<1,
>         P = spm_get(Inf,'*.img');
>end;
>V = spm_vol(P);
>gl = zeros(length(V),1);
>for i=1:length(gl),
>         for z=1:V(i).dim(3),
>                 img   = spm_slice_vol(V(i),spm_matrix([0 0
z]),V(i).dim(1:2),0);
>                 gl(i) = gl(i) + sum(img(:));
>                 fprintf('.');
>         end;
>         gl(i) = gl(i)*(det(V(i).mat)/100^3);
>         fprintf('\n');
>end;

The result is "ans = NaN"

This is baffling because when I run the scipt above on an unmasked data set
I get the correct output. I can view the masked data using "Display" within
SPM and everything looks good. Is there something that spm_masked does to
the data to alter it in someway, beyond masking?
Or
Am I completely misguided in my technique of masking and attempting to
extract the volume of an ROI.

Thank you for your time,
blaine