Hi, Cyril,
Thank you very much for your help!
I some time lose 10-15mm worth of border slices in the reslice result, when
I know from the parameter estimates that movement in any direction was at
most 5mm. What estimation and reslice options would you recommend for me to
try to save some information back? Is lower degree interpolation
necessarily better in terms not losing too much image in reslice?
Thanks a lot again!
Lu
-----Original Message-----
From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] On
Behalf Of [log in to unmask]
Sent: Thursday, April 19, 2007 12:53 AM
To: [log in to unmask]
Subject: Re: [SPM] Why is the reslicing result missing some outer most
slices
Hi there,
> I am doing "Realign: Estimate & Reslice". I notice the realigned and
> resliced 3-D image sometimes has the outer most couple of slices missing
> (i.e. coded all as zeros) and/or has some partial 2-D images. Could
someone
> tell me why? I notice when I use different interpolation options the
> extents of image missing are different. But I can't quite figure out a
> trend or reason yet.
Well this is explained by the use of a mask which corespond to the
intersection
of all images and- this mandatory in order to have a full time series even
at
the edges ... you should get different results using different interpolation
methods as the way you reconstruct the volumes differs and this is
particularly
visible at the edges .. you can notice that this effect varies from subject
to
subject due to their mvt.
Note that if you intend to normalize, there's no need to write your data at
this
stage: estimate and write the mean image then normalize and write (with a
coresgister step in between if you want); in SPM2 it will write down .mats
for
each image which will be use for the normalization, in SPM5, transformations
are stored in the header. Doing that you'll have only one interpolation :-)
Hope this helps
Cyril
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