Dear Wei
This could be caused by a number of factors, e.g. it could be a problem with the sequence or the positioning of the subject. In order to find out about the origin, a first thing to do could be to find out if the behavior is specific to this one subject, or if it happens to other images using the same sequence/scanner.
Best
Torben
Den 03/01/2010 kl. 03.09 skrev Huang, Wei (Psychiatry):
> Dear All,
>
> I've done realignment (estimate and reslice) on 246 EPIs (taken in one
> continuous scan), and the result showed a total 7mm continuous movement
> in the y direction (see attached 1st.fig), which led me doubt the
> quality of images and/or realignment. I went ahead to do another
> realignment based on the already realigned 246 scans and got the result
> of very small movement in all directions (see attached 2nd.fig), which
> made me believe the 1st realignment job was fine. However, I have never
> got such big continuous translation in one direction. Is this set of
> images reliable? Is there another way to check if anything is wrong
> with my images?
>
> Thanks,
> Wei
> <1st.fig><2nd.fig>
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