Hi @SuperClear,
yes, in the end it worked.
Are both your images 3d and not one 3d and the dwi 4d?
You can use the command provided by @maxpietsch here: ants reg.
You could use this to get get a 3d dwi before using above mentioned command:
ExtractSliceFromImage 4 anonym_b0.nii anonym_b0_volume0.nii.gz 3 0
then it should work.
With epi_reg I got as well huge data-sets, so I didn’t continue to use that.
For registration from t1 to mni152 i use the betted t1 (skullstrip via fsl bet) and register it with:
flirt [options] -in <inputvol> -ref <refvol> -omat <outputmatrix>
and use then the generated .mat file for other data sets from the same aquisition:
flirt [options] -in <inputvol> -ref <refvol> -applyxfm -init <matrix> -out <outputvol>
It seems to me that your images are not in talairach space, since for that, the anterior and posterior commissure should lie on a horizontal line.
But I think one of the experts should comment on those processes.
Still, I hope that helped a bit.
Best regards, Lucius