If the realignment is doing the right thing (use Check Reg - both before and
after realignment), then I would suggest checking with your local MR
physicist to see what may be changing between runs.
On Monday 14 July 2008 14:05, Christian Fiebach wrote:
> Dear colleagues,
> in a recent analysis we observed a weird pattern in the realignment
> very unsimilar to all previous studies.
> As you can see in the attached plot of the realignment parameters, we get
> no motion within runs, but very strong motion between scans, particularly
> in y-direction.
> This is a systematic pattern observed in more than one subject, producing
> up to
> 12 mm motion across the study in some subjects, while I am used to slightly
> more - and more systematic - within-run motion and less between-scan
> My first intuition was that we might have accidentally left on the Trio's
> online motion
> correction. However, this does not seem to be the case as the motion
> check box on the BOLD tab is not checked.
> I am very puzzled about this pattern. I might be overlooking something
> here, so I would be very thankful for any input or suggestion.
> Thanks in advance!