Fast-Relaxing Sodium Fraction in Brain Tumors

Motivation: Enhance the specificity of sodium (23Na) imaging in brain tumors. Goal(s): Distinguish intracellular and extracellular sodium distribution in glioblastoma. Approach: We assessed the fraction of fast-relaxing sodium (FT2*s) in 19 glioblastoma patients using a 3D radial 23Na pulse sequence with six echoes at 7T. Results: FT2*s was high in normal appearing white matter resembling expected intracellular behavior, and low in necrotic regions, akin to fluid-like environments. Values for contrast-enhancing tumors and adjacent edema were in between. The differentiation between normal brain tissue and changes in glioblastoma underscores the potential of FT2*s to improve the specificity of sodium imaging in brain tumors. Impact: The study could facilitate the establishment of the fast-relaxing sodium fraction as a diagnostic tool in brain tumors, potentially improving specificity in sodium quantification.