Be careful of using the realignment with dynamic PET data. Because the
pattern of intensity changes greatly over time, this will badly effect
the estimation of subject motion. The same issue applies to fMRI, but
because the activations are much smaller, they have less influence on
the alignment (but still some). The best way around this would be a
combined model for intensity change and subject motion - but there isn't
such a model in SPM.
If you have separate sessions of PET data, then you could use the Coreg
button to register the means together, and include the individual frames
of data that you want to move as "other".
Best regards,
-John
-----Original Message-----
From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]]
On Behalf Of Joel Dunn
Sent: Tuesday, May 15, 2007 5:39 PM
To: [log in to unmask]
Subject: [SPM] Apply realignments to other images
I'm just getting to grips with SPM5 so bare with me if there's an
obvious
answer.
How can I apply the realignment transformations from one set of images
to
another?
I have 2 sets of PET images from the same subject - one set has all
dynamic
frames summed (good signal/noise) the second has just a small subset of
frames summed. I've realigned the first set together and I would like to
apply those transforms to the corresponding scans in the second set.
With SPM2 I could have just copied the .mat files but SPM5 uses
transformation & rotational information from the nifti header(?) - how
can I
edit that?
Regards
Joel
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