Have you tried opening the mask in a program like MRIcro and flipping the X directions. Set X to something like -1 Hope this helps. Best, From: FSL - FMRIB's Software Library [mailto:[log in to unmask]] On Behalf Of David Gutman Sent: Monday, August 03, 2009 3:00 PM To: [log in to unmask] Subject: [FSL] Making symmetric ROI's in standard space Is there a clever trick so that I can just "flip" Right handed ROI's I drew on a mask to the Left side--- they were drawn on the fsl 1MM mask... I tried playing around with the eye.mat, but before I spend the next two years relearning/rembering linear algebra I decided to see if someone could just tell me! Thanks -- David A "trying not to reinvent the wheel" Gutman, M.D. Ph.D. Department of Psychiatry & Behavioral Sciences Emory University School of Medicine