> Date: Tue, 28 Jan 2014 16:24:31 +0100
> From:
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[log in to unmask]> Subject: Re: [SPM] longitudinal VBM8 for non-MRI nada
>
> Gabriel,
>
> just my 2 cents:
>
> > I have defined the origin in all my scans to the AC.
>
> Have you verified that the images conform to the orientation standard
> that spm expects? I.e., do they look as a template does when you load
> them in spm (i.e., coronal [top left], saggital looking left [top
> right], axial with r=r [bottom]) ? Have you tried normalizing the images
> using unified segment in spm?
>
> > As a second step I
> > notice that my images have different matrix sizes, i.e. voxel size of
> > 1.2x0.9x0.9, matrix = 135x256x256; and the follow-up scans have voxels
> > of 1.2x0.8x0.8, matrix = 120x188x188. For which I decided to reslice the
> > image so to increase the matrix of the second one. I'm sending you a
> > picture with an example before and after (attached image with the three
> > MRIs).
>
> If you really acquired all your timepoint 1 images in one way, and all
> timepoint 2 images in another way, then this, I am afraid, is a very
> serious problem. Even if you reslice the images (which is probably not a
> good idea as it introduces additional interpolation effects), they will
> still be acquired in two different ways, which means that it is not
> possible to disambiguate effects of time from those of sequence difference.
>
> > When I started the longitudinal VBM, it works till the "Coarse affine
> > Registration" when the error prompts, when I open the images they appear
> > to be rotated and their origin has been changed, see attached image with
> > the two MRIs.
>
> This usually only happens when the original image orientation and/or
> origin setting is unreasonably (to spm :) far off the expected
> orientation. I would suggest verifying spm can handle the images in the
> first place, and perhaps using the "set origin using center of mass"
> option in vbm8.
>
> Good luck,
> Marko
> --
> ____________________________________________________
> 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
>
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> http://www.medizin.uni-tuebingen.de/kinder/epn/
> ____________________________________________________
>