I want to calculate the mean FA value in the hippocampus.

Now I have already obtained the FA map for the whole brain in the native space.

And I have the aparc+aseg.mgz file after running the recon -all analysis.

Does someone know how to use freesurfer functions to obtain the hippocampus mask according to the DK atlas? I want to use this mask to calculate the mean FA value in the hippocampus.

Best regards,

Lin