Hi Dr. Lai, you can compute and script it by fslmaths. Cheers, Andreas Von: Chien-Han Lai <[log in to unmask]> Antworten an: FSL - FMRIB's Software Library <[log in to unmask]> Datum: Sun, 20 Nov 2011 15:33:24 +0800 An: <[log in to unmask]> Betreff: [FSL] question about how to fast to produce RD (radial diffusivity) (L2+L3)/2 Dear all FSL users: Can anybody tell me how to fast produce RD (radial diffusivity) (L2+L3)/2 from my DTIFIT results? Is there any fast command of FSL to produce a group of RD results from a group of DTIFIT results? Thank you. Best Dr. Lai