23Na magnetic resonance imaging: distribution of brine in muscle

Magnetic resonance imaging (MRI) has been used to characterize tissues in morphological studies. Here, 23Na NMR imaging was used to study the distribution in muscle of brine (5 M NaCl), injected before onset of rigor mortis. First, the distribution of brine was monitored in excised muscle from rabbits for 6 hr following arterial brine injection. Immediately after injection, distribution was clearly heterogeneous. After 6 hr, a steady state was achieved but the observed brine distribution was not fully homogeneous. Second, the same was done for ham processed in various ways (tumbling, cooking). Tumbling increased the homogeneity of distribution in our experimental conditions but only cooking afforded full homogenization of brine in ham. Concentrations of NMR-visible sodium in the muscles were appreciably lower than the expected values calculated from the volume of injected brine. The invisible sodium presumably has T2 values which are too short compared with the echo time in our conventional spectrometer.