Hi Dear Fs Experts I will post my question again, hopefully I can find an answer :)
In order to calculate the global white matter fractional anisotropy FA I used (wm.mgz ) the output of recon-all as a mask in the following command line mri_segstats --seg $SUBJECTS_DIR/015601/mri/wmparc.mgz --ctab $FREESURFER_HOME/FreeSurferColorLUT.txt --mask wm.mgz --i fa.anat.mgh --sum fa.stats
Kindly, Is this correct? Thanks Mohamad