Visual error with tckgen -exclude in tractography analysis

Development
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1

After processing all the different masks necessary for the representation of the different main tracts found in the CNS, I’ve got this kind of images:

tract
tract1275×816 169 KB

I can’t understand why there is a right hemisphery tract on my image if I told, specifically, tckgen to exclude all the information found on that hemisphere. The code used is the next:

tckgen -algorithm iFOD2 -fslgrad …/BThings/Suj_28.bvec …/BThings/Suj_28.bval -act annotations/Suj_28/registration/Suj_28_5TT_b0space.nii.gz -seed_image annotations/Suj_28/registration/Suj_28_AAL_rh_slfp_mask.nii.gz -select 1M -maxlength 250 -cutoff 0.06 -crop_at_gmwmi -include …/Freesurfer/Suj_28_FreeSurfer/dlabel/mask/rh_slfp_b0_mask.nii -exclude results/lh_AAL.nii results/Suj_28_structural_measures/Suj_28_wm_fod_norm.nii.gz results/Suj_28_structural_measures/Suj_28_1M_seeds_AAL_slfp.tck

the image has been edited with tckedit

tckedit results/Suj_28_structural_measures/Suj_28_1M_seeds_AAL_slfp.tck results/Suj_28_structural_measures/Suj_28_100k_seed_AAL_slfp.tck -number 100k

Does anybody know what is going on?

Thanks in advance!

2

Hello,

For the -exclude option, a binary mask is required. Could it be that the lh_AAL.nii image is not binarized?

Nick

3

Hey, Nick! The problem was the mask was created based on FreeSurfer information. Thus, it was a “surface” mask, not a volume mask. The internal cavities, plus the internalized grey matter, was excluded from the binary mask, and so, the -exclude from tckgen would not mind that info. But using 5TTgen and the 5TT image, I could get an image of the grey matter of the subject, and binarize it to get a RH mask and a LH mask, to avoid those hemispheres when needed.

But, anyways, thanks for the reply!

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