Tissue water referencing for 7T MRSI: Integrating proton density maps into quantitative metabolic mapping

Motivation: In magnetic resonance spectroscopic imaging, generating concentration estimates is desirable. So far, our approach has been limited by the need for WM/GM separation and literature values, limiting it to healthy subjects. To solve this, it can be replaced by PD map-based references. Goal(s): To test an approach of calculating concentration estimates within volunteers without relying on literature assumptions for reference. Approach: Use quantitative proton density maps to calculate water concentration maps for metabolic imaging at 7T. Results: We successfully used ME-GRE imaging to calculate water concentration maps. In healthy volunteers, these maps correspond well to the previous method. Impact: Using tissue water maps for MRSI concentration estimation allows to not only apply the method to healthy brains, but also to pathologies like gliomas. This will make 7T MRSI a better tool for studies.