Human brain iron mapping using atlas-based T2 relaxometry.

Several in vivo quantitative MRI techniques have been proposed as surrogate measures to map iron content in the human brain. The majority of in vivo quantitative MRI iron mapping methods used the age-dependent iron content data based on postmortem data. In this work, we fused atlas-based human brain volumetry obtained on a large cohort of healthy adults using FreeSurfer with T(2) relaxation time measurements. We provide a brain atlas-based T(2) relaxation time map, which was subsequently used along with published postmortem iron content data to obtain a map of iron content in subcortical and cortical gray matter. We have also investigated the sensitivity of the linear model relating transverse relaxation rate with published iron content to the number of regions used. Our work highlights the challenges encountered on using the simple model along with postmortem data to infer iron content in several brain regions where postmortem iron data are scant (e.g., corpus callosum, amygdale).