I was running freesurfer for a patient case of two time points. Will you suggest to run it as a group, such as one time point as a template and followed by longitudinal study, discussing atrophy or run these two time points separately as two individual, running everything such recon-all, dt-recon twice and comparing the result, such as thickness, volume and FA? BTW, I post a question about FA display before: will anything lead to a rectangular FA display, with extra diffusion out of the brain skull (no errors during recon and dt …)? 

Best, 

Qi