What sort of weighted fitting is done with the --wls option? I see that RESTORE (Chang et al, MRM, 2005) uses an iterative reweighted least-squares regression algorithm. Is there a way to see the final weighting of each voxel that went into the FA calculation?
Independent of the --wls option, I would like a way to specify, on an voxel-by-voxel and gradient-by-gradient basis, whether or not a voxel should be used in the FA calculation. I would like to omit artifactual voxels caused by a vitamin E capsule. Perhaps a 4D mask would allow me to do this. Rather than using the same 3D b0 mask for all subvolumes within the 4D DWI volume, an option to use a 4D mask for the 4D DWI volume would give me the flexibility I am looking for. For greatest flexibility, I suppose this mask could be a floating point weight rather than a binary [0,1] mask. But a binary mask would be allow me to drop artifactual voxels without dropping the entire gradient and without dropping the entire region across all gradients.
thanks.
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