Hi Bob,
this, if you want to do it perfectly right, is a tough problem, as you
would have to incorporate not only volume but also shape. However, I
believe getting an idea of whether things went right or wrong may be
achievable. Still, I am not sure what you mean by correlation, and I
would have probably started by simply looking at the voxelwise absolute
(or squared) differences, the latter having the nice side effect that it
punishes stronger deviation further.
However, deciding which approach is best-suited likely requires some
trial and error. You could try simulating "bad" normalization by moving
a copy of the template image out of alignment (so you know how bad the
disagreement is) and then use different approaches to see how they fare
in detecting this disagreement.
I am sure something like this has been done before, though; a quick
search brings up Yassa and Stark, NeuroImage 2009, Hoeksma et al, Clin
Neurophysiol 2005, Kochunov et al, NeuroImage 2008, Hashioka et al, Int
J Comput Assist Radiol Surg 2012... as I said, if you want to do it
perfectly right... ;)
Cheers,
Marko
Bob Spunt wrote:
> Dear SPM experts,
>
> I have been using the correlation between the mean of the normalized and
> smoothed functional images and the EPI template to measure the quality
> of the results of normalization. Although this seems like a crude
> measure, it appears to be fairly good at catching bad subjects. I have
> two questions:
>
> 1) Is there anything problematic with this method?
>
> 2) Do you have any recommendations for more accurate methods?
>
>
> Any advice is much appreciated, and thanks in advance.
>
> Sincerely
>
> Bob Spunt
> Postdoctoral Fellow
> Social Cognitive and Affective Neuroscience Labs
> Department of Psychology
> University of California, Los Angeles
>
--
____________________________________________________
PD Dr. med. Marko Wilke
Facharzt für Kinder- und Jugendmedizin
Leiter, Experimentelle Pädiatrische Neurobildgebung
Universitäts-Kinderklinik
Abt. III (Neuropädiatrie)
Marko Wilke, MD, PhD
Pediatrician
Head, Experimental Pediatric Neuroimaging
University Children's Hospital
Dept. III (Pediatric Neurology)
Hoppe-Seyler-Str. 1
D - 72076 Tübingen, Germany
Tel. +49 7071 29-83416
Fax +49 7071 29-5473
[log in to unmask]
http://www.medizin.uni-tuebingen.de/kinder/epn
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