Cesium‐133: A potential reporter of the hepatic uptake of contrast agents

NMR spectroscopy of intracellularly located 133 Cs has been used to monitor the uptake of Gd‐EOB‐DTPA by the isolated rat liver. As shown by 31 P spectroscopy, accumulation of 133 Cs ions in hepatocytes does not produce detectable effects on the metabolism. The hepatic internalization of Gd‐EOB‐DTPA was followed by the paramagnetic relaxation enhancement of the intracellular 133 Cs ions, and confirmed by parallel quantitations of Gd and Cs run by inductively coupled plasma (ICP) analysis of liver samples and aliquots of perfusate. The relaxation data significantly underestimate the Gd content, suggesting a potential compartmentation of Cs + and/or the contrast agent. Magn Reson Med 45:711–715, 2001. © 2001 Wiley‐Liss, Inc.