Quantitative 23Na Magnetic Resonance Imaging of Model Foods

Partial Na-23 MRI invisibility in muscle foods is often referred to as an inherent drawback of the MRI technique, impairing quantitative sodium analysis. Several model samples were designed to simulate muscle foods with a broad variation in protein, fat, moisture, and salt content. Na-23 spin-echo MRI and a recently developed Na-23 SPRITE MRI approach were compared for quantitative sodium imaging, demonstrating the possibility of accurate quantitative Na-23 MRI by the latter method. Good correlations with chemically determined standards were also obtained from bulk Na-23 free induction decay (FID) and CPMG relaxation experiments on the same sample set, indicating their potential use for rapid bulk NaCl measurements. Thus, the sodium MRI invisibility is a methodological problem that can easily be circumvented by using the SPRITE MRI technique.