Tckgen anisotropic voxel size


I’m processing a dataset with anisotric voxel size (1.35x1.35x2.7). I did all the preprocessing and now I have to run tckgen I have some doubts that I hope you could help me:

-Is there any step that requieres isotropic voxel size? (dwidenoise, mrdegibbs)

-Could I run tckgen with anisotropic voxel size? or do I need to resample?

-If I can do it? how the default parameters that depend on the voxel size are selected?

Thanks in advance.

Best regards,


Everything should work. If it doesn’t, we’d like to know about it!

I think the only parameters that depend on voxel size are settings like step size in tckgen. I’m pretty sure we use the geometric mean of the voxel sizes as the single estimate of voxel size (though I’d need to check the code to confirm, it’s been a while…). Either way, it should be sensible.

Otherwise, tckgen performs all its internal processing in real/scanner coordinates, precisely to avoid issues related to different voxel grids between the input data and any other images involved in the process (i.e. ROIs, 5TT, etc.).

Hi @jdtournier,

Thanks for your reply, I tried and the results so far look good, but I put all the parameters manually. I let you know if I find anything strange.

Best regards,