About calculating FA(Fractional Anisotropy) with TensorRelativeAnisotropyImageFilter

Beginner Questions
1

Hi there, I tried to calculate FA and PDD for streamlines tractography with TensorRelativeAnisotropyImageFilter.

And I basically follow the workflow in the website (ITK: Examples/Filtering/DiffusionTensor3DReconstructionImageFilter.cxx), But as a result, the FA image and colored-FA image seems a little bit noisy and mosaic.

image
image270×258 23.3 KB
image
image270×286 22.3 KB

While it should look like this:

image
image345×390 43.8 KB

could you please give me some advice?

I think there’re maybe some reasons:

  1. some preprocessments and postprocessments I skipped to make FA more good-looking
  2. some settings in TensorRelativeAnisotropyImageFilter should be set but I forgot
  3. before calculating FA and PDD I should up-sample the image, but… how big is reasonable?
  4. …etc? I have no idea…

Great thanks for any help!