Conventional χ-separation compared to self calibrated method (BIOPHYSICSS-DL) with histological validation

The χ-separation method determines para- and diamagnetic susceptibility tissue compartments correlating to iron and myelin in the brain respectively. The method presupposes subject invariant relaxometry coefficients and compartments disregarding the changes in those parameters in disease or postmortem cases. We implement a biophysically informed autoencoder network developed for single subject use (BIOPHYSICSS-DL) to determine underlying biophysical model coefficients from individual datasets. We expand the current model with different combinations of relaxometry and susceptibility data to produce a self-calibrated χ separation method finding the network comparable to standard methods for iron and predicts myelin distribution more closely to ground truth histology.