INFLUENCE OF GADOLINIUM CHELATES ON P-31 MAGNETIC-RESONANCE SPECTROSCOPY OF THE LIVER

RATIONALE AND OBJECTIVES. The potential of gadolinium compounds (Gd-ethoxybenzyl-DTPA [Gd-EOB-DTPA], gadopentetate dimeglumine [Gd-DTPA], and Gd-chloride [GdCl3]) to enhance the signals from intracellular phosphorus-31 nuclei in the liver was investigated. METHODS. After intravenous administration of Gd-EOB-DTPA, Gd-DTPA, and GdCl3 to rats, liver phosphorus metabolites (inorganic phosphate [Pi], phosphomonoester [PME], and adenosine triphosphate [ATP]) were measured by phosphorus-31 magnetic resonance spectroscopy (MRS). The dose of each compound was 0.2 mmol Gd/kg. Saline was used as a control. RESULTS. The intensities of the phosphorus metabolite signals in the liver showed only minor changes after administration of Gd-DTPA and GdCl3, but increased after Gd-EOB-DTPA. The signals of Pi and PME were enhanced more than those of ATP. The alpha peak of ATP increased by 21.7%, Pi by 61.2%, and PME by 49.2%. CONCLUSIONS. The signal intensities of the phosphorus metabolites in the liver were not influenced by GdCl3. Using Gd-DTPA, only a slight enhancement could be detected. The greatest enhancement was observed with Gd-EOB-DTPA, which has access to the phosphorus metabolites within the hepatocytes. The injection of Gd-EOB-DTPA results in better detectability of the Pi signal.