In-vivo high-resolution χ-separation (chi-separation) at 7T

Motivation: High-resolution χ-separation at 7T can delineate detailed structures related to iron and myelin concentrations in the brain. However, it has the challenge of requiring an R2 map, which is not practical at 7T due to SAR and scan time. Goal(s): Our objective is to generate high-resolution χ-separation maps at 7T. Approach: An R2* 7T-to-3T conversion network to transform a 7T R2* map into its 3T counterpart is developed. Then, 𝜒-separation is processed via QSMnet, χ-sepnet-R2*, and resolution generalization. Results: We successfully produced high-quality and high-resolution 𝜒-separation maps only from multi-echo gradient echo data at 7T. Impact: This study suggests a solution for the technical challenge of requiring R2 map in 7T χ-separation, enabling high-resolution (=650 um) χ-separation. This may benefit the analysis of iron and myelin concentration changes in various neurodegenerative diseases through detailed structural examination.