Dear Jesper,
> The "minimal" data that topup-eddy needs to correct for both susceptibility and eddy currents is b0 blip-up-blip-down. Maybe two of each to be on the safe side dwi sampled on the whole sphere with blip-up OR blip-down.
> I have had good results with such data when there are 60 or more directions. It is POSSIBLE that it would work also for fewer directions, but I haven't tested that.
Thank you for your info. Also for the message, addressed to Andreas (2 x 80 dirs). I now it always depends on what I want to examine and the time I am willing to afford. If I was planning a new study - would it be more benefitial to do 2 x 80 dirs or something like the Rockland group (137 dirs, http://fcon_1000.projects.nitrc.org/indi/pro/eNKI_RS_TRT/FrontPage.html) plus b0s blip-up-/down?
Best,
Martin
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