No, that flag is for something else. Probably the easiest thing to do is in matlab, eg,
a = MRIread('dwi.nii.gz');
a.vol = prod(a.vol,4).^(1/a.nframes);
MRIwrite(a,'geomean.nii.gz');

btw, I've never heard that you can compute the ADC this way, but maybe it's right

On 2/11/2021 6:53 AM, Mateus Aranha wrote:

External Email - Use Caution

Dear all,

I have 32 directions DTI images and I need to compute DWI and ADC maps from these images. As far as I know the DWI is obtained by calculating the geometric mean of the 32 b1000 images. Can it be done with mri_concat --gmean Ng?

Many thanks,

Mateus
_______________________________________________
Freesurfer mailing list
Freesurfer@nmr.mgh.harvard.edu
https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer