Spherical Harmonic Coeffs to DWI images


Hello all in the MRtrix Community,

I’m trying to replicate the method of Mirzaalian et al., 2016, in which spherical harmonic deconvolution is used to harmonize DMRI data from different scanners (with similar acquisition schemes). Basically they calculated scaling factors on the SH coefficient images using RISH values from their test subjects at each site. I can see that the dwi2fod command in MRtrix gets me part of the way there to implementing this – I now have coefficient images. But is there a command to go in the opposite direction? That is, to recreate the DWI data from the coefficients after I modify them? The idea would be that, using this method, any DMRI processing software should be able to handle the harmonized images.



I have a feeling you’re after the amp2sh and sh2amp commands for this. dwi2fod does a fair bit more than a straight SH fit, which I think is what you’re after here?


Those look like they will do the trick. Thank you!