error in dti_diffeomorphic_population

[Marisa]

Dear Gary,

we are currently working on a DTI analysis of a subsample of the eNKI dataset.

We carefully followed the steps as provided on www.diffusion-imaging.com and www.dti-tk.sourceforge.net, however, when running the command *dti_diffeomorphic_population mean_affine3.nii.gz subj_list_file_aff.txt mask.nii.gz 0.002* the following errors occur:

1) Reading sdt_aff_diffeo.df.nii.gz ... ** ERROR (nifti_image_read): failed to find header file for 'sdt_aff_diffeo.df.nii.gz'

2) Reading mean_df.nii.gz ... ** ERROR (nifti_image_read): failed to find header file for 'mean_df.nii.gz'

As you suggested to previous users with the same error, we tried the registration with the tutorial data, but the exact same errors occurred...

In regard to your prior suggestions on similar errors, we checked and confirmed the following:

- the data are DTI (not DWI) volumes

- the DTI volumes are in NIfTI tensor format

- the DTI volumes are the correct diffusivity unit

- non-brain tissue is removed

- DTI volumes do not contain significant outliers

- the DTI volumes are SPD

- the DTI volumes share a common voxel space

--Would you have any idea or suggestions regarding why the file 'sdt_aff_diffeo.df.nii.gz' cannot be created as part of the command dti_diffeomorphic_population?

Thank you very much in advance for your help!

Marisa