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Dear FSLers I have some patient data which was half collected at b=1000 and half at b=2000 - sequence changed but we didn't notice :( I scanned two controls with both b-values, registered the diffusivity images, then fitted curves to scatterplots for voxel-wise measures of MD and L1-3 between the two scans (screen grab attached for MD in one of the controls). I would like to correct the diffusivity values for the b=2000 group to match the b=1000 group so i can study the diffusivities for all patients. I am interested to know if anyone has done this before? i get very good agreement between the curve fits between the two control subjects but i'm not sure how many more i should double scan. also, are there any problems with correcting the diffusivity values like this that I have not foreseen? i understand that the SNR is different but does this prohibit diffusivity correction? cheers Scott -- ======================== Scott Kolbe MS Imaging Group Howard Florey Institute & Centre for Neuroscience University of Melbourne VIC, Australia, 3010. ph: +61 3 8344 1887 email: [log in to unmask] website: www.neuroimaging.org.au/index.php?id=383 -- ======================== Scott Kolbe MS Imaging Group Howard Florey Institute & Centre for Neuroscience University of Melbourne VIC, Australia, 3010. ph: +61 3 8344 1887 email: [log in to unmask] website: www.neuroimaging.org.au/index.php?id=383