Hi Andy,
Thanks for your email - these look quite nasty indeed. We had a quick
look and think that most of these maps are actually physics/scanner
related, e.g. all these single slice components are possibly related to
what is sometimes called a 'slice dropout' (afaik related to a
mis-timing between applying the slice-select gradient and the RF pulse
- not totally sure and you should probably ask you local physicist) Are
we right in thinking that this is a spiral epi data set? #45 could
possibly be the spiral version of the standard epi ghost and the
single-slice-medial-line artefacts could be caused by some instability
in the shim?
In order to get a better feel for what's going on I'd suggest to
collect some phantom data and run melodic on the non-pre-processed data.
Did you also find the activation you were interested in? If not, the
'filter' option in melodic might help cleaning up the data, there's a
tutorial on how to do this available at
http://www.fmrib.ox.ac.uk/fslcourse/melodic/_3200_denoise.fpd/index.html
good luck and feel free to let us know how you're getting on
best
christian
On Monday, Jun 30, 2003, at 15:57 Europe/London, Anda Pacurar wrote:
> Hi.
>
> MELODIC is an amazing software and it really changes the way you look
> at
> your data!
>
> The fMRI data that I used for MELODIC - ICA analysis was preprocessed
> for
> MC using AFNI.
>
> I think that the following components pick up artifacts in my data and
> I
> wonder about the possible source of the artifacts.
>
>
> #1.
> http://www.rotman-baycrest.on.ca/fMRI_data/ICA/IC_21/IC_21.html
>
> #2.
> http://www.rotman-baycrest.on.ca/fMRI_data/ICA/IC_4/IC_4.html
>
> #3.
> http://www.rotman-baycrest.on.ca/fMRI_data/ICA/IC_42/IC_42.html
>
>
> #4.
> http://www.rotman-baycrest.on.ca/fMRI_data/ICA/IC_2/IC_2.html
>
> #5.
> http://www.rotman-baycrest.on.ca/fMRI_data/ICA/IC_45/IC_45.html
>
> #6.
> http://www.rotman-baycrest.on.ca/fMRI_data/ICA/IC_6/IC_6.html
>
> #7.
> http://www.rotman-baycrest.on.ca/fMRI_data/ICA/IC_14/IC_14.html
>
> #8.
> http://www.rotman-baycrest.on.ca/fMRI_data/ICA/IC_33/IC_33.html
>
> #9.
> http://www.rotman-baycrest.on.ca/fMRI_data/ICA/IC_56/IC_56.html
>
>
> Thank you.
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