[Mristudio-users] test-retest

[susumu mori]

Hi Miguel,

You can do it using Diffeomap (or FSL or SPM). First do tractography
in image 1 and 2 independently. Save the results as a 3D 1/0 mask in
DtiStudio.
Then run a rigid transformation between the image 1 and 2. You can do
FA vs FA but b0 vs b0 could be easier because FA maps could have some
random intense pixels outside the brain that may interfere with the
rigid alignment. Save the transformation matrix and apply it to your
1/0 binary fiber mask image. Then you can superimpose the aligned #1
and original #2 see the reproducibility. You can do all these very
easily by DiffeoMap.

Susumu

On Wed, Mar 30, 2011 at 12:56 PM, Miguel Burgaleta
<miguel.burgaleta at uam.es> wrote:
>
> Hi,
>
> We have a sample of DWI acquired twice for each subject, 1 month in
> between, and would like to analyze the test-retest reproducibility of
> a selection of tracts with DTIStudio. We would also like to see the
> effect of outlier pixel rejection on the reproducibility. However, we
> are not sure of how to proceed so that we control for the intra-rater
> reliability.
>
> One option we thought of is to perform tractography at time 1, save
> both binary tracts and ROIs, and then register each FA image in time 1
> to its corresponding FA image in time 2, apply that transformation to
> the ROIs and get the tract for time 2. Is this feasible with DTIStudio?
>
> If you know a better way to do this, please let me know.
>
> Best,
> Miguel
>
>
>
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