Hi Mark,
thanks for the message. I was afraid that it's difficult, but as you have much
more experiences with registration than me, I thought you may have
a "recipe".
Thanks a lot and have a good day.
Martin
On Wednesday 27 September 2006 14:38, Mark Jenkinson wrote:
> Hi Martin,
>
> I'm afraid that this is a very difficult problem indeed, and still
> unsolved in the research field. What makes it difficult is that
> the motion introduces other artifacts which affect the ability
> of registration to align things well. Also, aligning a single slice
> independently to a reference 3D volume is typically very poorly
> conditioned and the results are inaccurate. When put together
> this makes slice-by-slice correction, like you need to do, quite
> unreliable and inaccurate. So we haven't released any tools to
> do this, although we have tried some methods in the past and
> are currently working on an integrated system to deal with the
> artifacts and the motion together. However, this is still a while
> off in the future.
>
> So at the moment I'm afraid that if you have enough motion
> that it is obvious to the eye, then registration just won't work
> well and your artifacts will probably spoil any data anyway.
>
> Sorry that I don't have better news.
> All the best,
> Mark
>
> Martin Kavec wrote:
> >Hello everybody,
> >
> >I have quite a lot of DTI series of newborns, where a baby moved between
> >acquisitions of successive slices, so the slices look like a "fan". There
> > are no ghosting artifacts, though. In some cases it is so bad (poor baby
> > was probably too excited) that I would have to skip most of the DTI
> > volumes, or the baby moved during b=0 scan. I still have anatomical
> > images, which look fine, so I could eventually use those as a reference.
> >
> >Do you have any idea, how can I correct for this kind of motion? Can FLIRT
> >cope with is?
> >
> >Thanks a lot in advance.
> >
> >Martin
--
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Senior Research Associate in Neuroradiology
MR Unit
Erasme Hospital
808 Route de Lennik
B-1070 Brussels
BELGIUM
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