[Mristudio-users] AIR image dimensions/ Talairach WMPM/Eigen vector flipping/ROI Error

[susumu mori]

Before LDDMM, please make sure to do linear registration. Non-linear
solutions always depend on a good initial estimation by a linear solution.

On Wed, Dec 14, 2011 at 1:40 AM, sd <sd880131 at 126.com> wrote:

> Hi，
> I just wonder that which subject should I submit for the LDDMM process？The
> initial images or the images after linear transformation？
> Sandy
>
> At 2011-12-13 23:32:47,"Bill Quinn" <billquinndme at yahoo.com> wrote:
>
> Hi mri-studio users and programmers,
>
> First of all, thank you for well written program and also your fantastic
> follow up service. If possible I would like to ask a couple of questions
> just to clarify some questions that I have about the basic workings.
>
> 1. In Diffeomap I perform Air Linear Registration in order to align my
> data with that of the Template (in my case I use the Talairach atlas). My
> images are 256*256*55 and I normalise it with the template of dimensions
> 192*192*136. How much does the difference in image size affect the accuracy
> and reliability of the subsequent analysis.
>
>    - As an additional to ensure the best LDDMM result, is the contrast of
>    the two images the most important in setting up the images before entering
>    the LDDMM screen?
>
>
> 2. When I load the Talairach WMPM from diffeomap as an ROI the regions of
> interest are loaded as object 1,2 etc. Is it possible to get the name of
> each region of interest? When I perform the intensity measurements using
> the WMPM I get the a table listing a the same amount of parts as the
> objects i.e. in the case of Talairach 170. I then use the following paper
> to find what the abbreviations stand for:
> *
> **Oishi et al,** Atlas-based whole brain white matter analysis using
> large deformation diffeomorphic metric mapping: Application to normal
> elderly and Alzheimer’s disease participants*
> euroimage 2009 June ; 46(2): 486–499. (Appendix A part 4)
>
> Is this the correct approach? Or is it the that the regions of interest in
> the ROI objects box contain these parts as can be seen when I choose the
> button under Atlas: *WMPM of division of defined ROIs*
>
>
> 3. When I load or create the tensor image file (.d file) in DIffeoMap I am
> asked if I want to flip the eigenvectors. If I save the file as
> eigenvectors being flipped when I created the file do I also have to flip
> them again while opening the file afterwards or do I assume they are now in
> the correct direction?
>
> 4. Finally, when I create an ROI in either DTIStudio or ROI editor I save
> it as a binary map. When I then try to reload it in the fibre tracking
> section I am informed that the* "Image parameters in this file are not
> consistent with with current ones, continue?"* When I select yes the ROI
> loads in the expected position. Is it a normal occurance to get an error
> even though I created the ROI in the same image during the same DTIStudio
> session?
>
> If any of these questions have already been answered, please just point me
> to the appropiate link.
>
> Thank you for you time,
>
> Best Regards,
>
> William Quinn
>
>
>
>
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