pub const DR_KIM_2025_COSMOS: f64 = 114.0;Expand description
χ-separation’s relaxometric constant D_r re-measured against COSMOS, in Hz/ppm.
Kim et al. 2025 (Human Brain Mapping 46(4):e70136) repeated Shin’s regression using COSMOS-reconstructed χ maps instead of single-orientation QSM and obtained 114 Hz/ppm, attributing the difference to the QSM algorithm behind the training data. The SNU-LIST toolbox’s own script carries the same note against this value.
It is the right constant for a COSMOS-referenced χ — which is what the χ-sepnet family of
networks was trained on, and why
ChiSepNetNorm and
R2PrimeNetNorm bake 114 in as a fixed training
normalisation rather than a tunable. Those are deliberately not defined in terms of this
constant: a network’s normalisation cannot move when the field’s best estimate of the physical
relaxivity does, and tying them together would invite exactly that edit.