Subject-specific χ-separation method: the effect of introducing a personalised relaxometric constant Dr

χ-separation is a recently proposed biophysical model to separate the χ-positive and χ-negative contribution of magnetic susceptibility sources in the brain. Such a model relies on assuming a certain relaxometric constant (Dr) calculated as the mean of a group of healthy subjects. Here we demonstrate that Dr is subject-specific and if used in place of the average value, it affects the χ-positive and χ-negative maps in a structured way, while their sum remains similar.