Also note that this is an appallingly bad segmentation, probably because the
initial affine registration went badly wrong. You need to have the data
approximately aligned with the tissue probability maps in order for the local
optimisation to work. The reason for this is that the tissue probability
maps contain no information about what should be outside the brain. The
registration model is therefore suboptimal for images with skull, scalp etc.
Best regards,
-John
On Tuesday 29 January 2008 21:14, On Tsang wrote:
> Hello SPMers,
>
> I have another question concerning the SPM segmentation algorithm,
> spm_preproc. This question is rather basic and quite fundamental.
> Essentially, I suspect that the algorithm does not actually retain the
> Native space in the output. Can anyone else confirm this? More
> specifically, I used the IBSR database which consists of
> positionally-normalized-Talairach datasets, and the output of spm_preproc
> is no longer in
> positionally-normalized-Talairach space. I am attaching a screenshot
> depicting GM segmentation for one such dataset. The image can also be found
> at the following location:
>
> http://www.utdallas.edu/~okt061000/native.png
>
> Please can anyone confirm this behavior? I would really appreciate it.
> Thanks in advance!
>
> Best Regards,
> On
|