Fig. 6:

The purpose of these results was to explore the effect of N, the number of volunteers, on predicted T₁ (a-b) and T₂ (c-d) values. The number of subjects was varied from its actual (maximal) value of 8 all the way down to 2, whereby data from only one volunteer would be used for training and one for validation purposes. Reference T₁ and T₂ values are tagged with ‘ref’ for comparison. Overall, there were no drastic observable effect/improvement as N is increased beyond two possibly because: 1) each volunteer contributes about 12,000 signal-containing voxels, 2) the NN is fairly simple and trained on a per-voxel basis, 3) the main limiting factor at this point might be the spatial alignment of MPME and training data, an effect that might hide more subtle N-related effects.