Imaging of intracellular sodium with shift reagent aided 23Na CSI in isolated rat hearts

23Na chemical shift imaging (CSI) in conjunction with shift reagents was used to obtain images of intracellular (Nai) and extracellular sodium (Nae) in isolated rat hearts. It was demonstrated that the increase of Nai concentration in ischemic myocardium can be detected with this technique. 3D acquisition-weighted 23Na CSI datasets with a nominal spatial resolution of 1.7 × 1.7 × 2.9 mm were acquired in 30 min in normoxic hearts and in globally or locally ischemic hearts. The shift reagent Tm(DOTP)5− was used to discriminate Nai and Nae signals. Nai maps could be generated in ischemic hearts, but not in normoxic hearts as the signal-to-noise ratio is too low. The Nai signal increased by more than 100% and the Nae signal decreased by more than 50% in myocardium of globally ischemic hearts (n = 3) compared to normoxic hearts (n = 3). In hearts with an acute occlusion of the left anterior descending coronary artery (n = 3), there was a local Nai signal increase in the anterior wall in the range of 60–110% compared to remote, normoxic tissue. Magn Reson Med 48:89–96, 2002. © 2002 Wiley-Liss, Inc.