Hello,

after reading the paper I still have some questions regarding the extent and methodology behind the DTI modification.  If I understood correctly, the DTI volume is modified after the first simulation of the tumor mass expansion, taking as input the degree of expansion or compression which affects the the diffusivity and principal diffusion direction.

My first question is, does the result of the infiltration process affect the DTI ?      or is it the DTI volume fixed after the tumor mass expansion, irrespective of the ammount of simulated infiltration?


Another question regarding the parameters that control the DTI,   can you provide typical values for them?   (white-matter tensor multiplier and gray-matter tensor multiplier)    what else would you suggest for generating the most reallistical DTI deformation (preferrably taking into account the infiltration and contrast-enhancement)?


 Thanks for your kind attention.

Best regards,

Andrés Méndez

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