Multiparametric statistical quantification of the heterogeneity of free Na+ concentration by 19F NMR spectroscopy

Sodium(I) (Na⁺) plays a key role in basic cell function. Noninvasive methods for measuring intracellular Na⁺ concentrations ([Na⁺]_i) in biological tissue have been developed on the basis of ¹⁹F NMR spectroscopy. By contrast, ²³Na MRI at most provides approximate (relative) contributions of intracellular Na⁺ to total ²³Na by relying on a number of theoretical assumptions, as it does not detect Na⁺_i selectively. Since [Na⁺]_i values are often not uniform throughout a given tissue volume (or voxel), we have designed an approach for quantifying total [Na⁺]_i heterogeneity by exploiting the lineshape of the ¹⁹F resonance of an appropriate [Na⁺]_i reporter molecule.