Hi all,

Just a quick query following up on exchange posted a wile back about the
order of EC correct and series averaging ...


Mike Cohen: "I have a 60-direction DTI scan that is repeated 3x for subsequent
averaging ... Is it better to run eddy_correct on each of three acquisitions and
then average them, or average them first and then run eddy_correct?"

T. Behrens:  We have exactly the same data - what we do is merge all data
sets into a single big 4D file, run eddy_correct on this big file, then
split it up into 3 averages and average these.

I have the same protocol (only 30 dirs due to time constraints
unfortunately).  I have interleaved b0s throughout the 30 diffusion weighted
scans which I average and move to the beginning of the diffusion weighted
scans for subsequent processing.  Should I do this before eddy_current
correction?  Or should I run EC on the whole dataset as acquired,
referencing the first b0 acquisition, and then do the averaging for both
diffusion and non-diffusion-weighted volumes as per the response above?

Many thanks,


Gary Turner, Ph.D.
Helen Wills Neuroscience Institute
University of California, Berkeley
132 Barker Hall
Berkeley, CA