Hi Bob,
Thanks! That is a very interesting idea. I read their protocol a bit but did not realize they were doing in this way. I agree with you that the field map result is semi-reasonable. For some parts it seems to make the EPI match structure better, but for some other parts it can over compensate (if I am not doing things wrong) and the performance seems to vary with subjects.
I will give a try for my future scans. So if my scan is A>>P phase encoding direction, should I just add a few TRs of scan with P>>A phase encoding direction?
Mingbo
