[Mrtrix-discussion] rotating gradient directions

[Donald Tournier]

Hi Zita,

I'm afraid there if no motion correction included in MRtrix currently. Most
people seem to use FSL's eddy-correct to do this, you find quite a few
emails about this on the mailing list. There is a search box on the MRtrix
mailing list front page, I'd recommend you try searching through the
archives that way of you're interested.

As to the second part of your question, yes I'd agree that when the motion
is large, no motion correction algorithm is going to manage to salvage the
data all that well, since there will be a fair amount of signal corruption
too. Still, it's probably worth doing in most cases anyway. One issue that
is still not fully resolved is how to handle high b-value data, given its
typically low SNR and highly variable contrast. Again, you'll find the
issue had been raised in previous emails on this list.

Hope that helps,

Donald.
On 20 Apr 2013 01:02, "Patai, Zita" <e.patai at ucl.ac.uk> wrote:

>  Dear MRTrixers****
>
> ** **
>
> I have a dataset in which scans were acquired in 3x20 directions, ie. I
> have 3 sets of data per subject.****
>
> I was wondering if there was a way to correct for gradient direction
> rotation, if for example the subject moved between scans, is there a way to
> correct for the movement but also then to adjust the b-values accordingly?
> ****
>
> ** **
>
> I have seen that this is possible in FSL, but I wanted to just stick to
> MRTrix if that was possible.****
>
> ** **
>
> Also, is this actually an important issue? If the head-motion is very
> large, presumably motion correction will not work anyway?****
>
> ** **
>
> Thanks for your help,****
>
> zita****
>
> ** **
>
> _________________________****
>
> Eva Zita Patai****
>
> Postdoctoral Research Associate****
>
> UCL, Institute of Child Health****
>
> e.patai at ucl.ac.uk****
>
> 020 7905 2730****
>
> ** **
>
> _______________________________________________
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> Mrtrix-discussion at www.nitrc.org
> http://www.nitrc.org/mailman/listinfo/mrtrix-discussion
>
>
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