Hi,
This is a consequence of FEAT's intensity normalisation.
It is fine and will not affect any of your diffusion parameters
so you can continue to do your analysis with these images.
All the best,
Mark
On 24 Nov 2011, at 08:21, Andi Heckel wrote:
> Dear FSL-list,
>
> I have a question regarding the FEAT-unwarp procedure, which i started using to unwarp DWIs.
>
> It works fine, but I noticed that the absolute voxel-wise intensity values of the unwarped images are ~70 times higher compared to the original images. As input to unwarping in FEAT i used a) the betted magnitude image and b) a phase-difference image, which has been scaled to -pi...+pi, unwrapped with Prelude, divided by delta-TE to get rads/second and centered to the median.
>
> According to fslstats -R, my distorted DWI-b0 image ranges from 0.000000 4095.000000, wheras the undistorted image ranges from 0.000000 295356.68750
>
> Is this normal behaviour or has something gone wrong ?
>
> Thank you very much in advance,
> andi heckel
>
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