Triple quantum (TQ)-filtered 23Na NMR spectroscopy and the shift reagent, TmDOTP5-, have been used to evaluate the contributions of intra- (Na(i)+) and extracellular (Na(e)+) sodium to the TQ-filtered signal in the rat liver, in situ. Na(e)+ contributed significantly to the total TQ- filtered signal in live animals, and the intensity of this signal did not change postmortem. The TQ-filtered Na(i)+ signal increased by approximately 380% over a period of 1 h postmortem, whereas the single quantum (SQ) Na(i)+ increased by 90%. The constancy of the TQ-filtered Na(e)+ signal indicates that changes in total TQ-filtered 23Na signal intensity in liver (without a shift reagent) may accurately reflect changes in TQ-filtered Na(i)+ signal intensity. The large percent increase in the TQ-filtered Na(i)+ signal as compared to the SQ signal suggests that the fraction of Na(i)+ interacting with macromolecules increases after death.
- Multiple quantum NMR
- Na MRS
- Shift reagent
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging