  Iron and myelin are primary susceptibility sources in the human brain. These
substances are essential for healthy brain, and their abnormalities are often
related to various neurological disorders. Recently, an advanced susceptibility
mapping technique, which is referred to as chi-separation, has been proposed,
successfully disentangling paramagnetic iron from diamagnetic myelin. This
method opened a potential for generating high resolution iron and myelin maps
in the brain. Utilizing this technique, this study constructs a normative
chi-separation atlas from 106 healthy human brains. The resulting atlas
provides detailed anatomical structures associated with the distributions of
iron and myelin, clearly delineating subcortical nuclei, thalamic nuclei, and
white matter fiber bundles. Additionally, susceptibility values in a number of
regions of interest are reported along with age-dependent changes. This atlas
may have direct applications such as localization of subcortical structures for
deep brain stimulation or high-intensity focused ultrasound and also serve as a
valuable resource for future research.
