Hi Andres,

The result of the infiltration process currently does not affect the DTI. The tensors determine the direction of likely infiltration, but there is no simulation of the structural effects of the infiltrating tumor cells.

Regarding the tensor multipliers, the general approach in the literature is make white matter more diffusive than gray matter.  Some model this by setting the white matter multiplier to be 100x the gray matter multiplier (e.g., 100 to 1). You can adjust the actual values to get different behaviors, but avoid setting them too large as it will result in numerical instabilities.

Regards,
Marcel