Dear Ronniek, Explore DTI, as you can prove, use all the FOV. Black space (or 0 value in.mat) are taking account in ExploreDTI, but if you want to use ExploreDTI informing coordinates, you need to delete the useless [ 0 ] space. ExploreDTI philosophy isn't a parametric spatial statistics factory. Then, manually calculate parenchyma native space size using boundaries cairns (occipital pole, frontal pole....).
Applying a simple mathematical rule to perform what you want, use [ 1 1 1] for [ X Y Z ], then, you will be using coordinates to inform and make comparisons. Of course, Talso to make comparisons have ATBS, or/and b) do the mathematical handcraft [ 1 1 1 ] method.
Recapitulation: Black- zero FOV space are considered in ExploreDTI 'coordinates', but you are not interested in black- zero part.
At first, remember to be sure what you have in your hands. Taking into account your voxel size, in millimetres, ¿how long, wide and high are the native space you have? Don't include black-0 space. Translate it into [ Xmm Ymm Zmm ]