Dose-Dependency and Rate of Decay of Efficacy of Resovist on MR Images in a Rat Cirrhotic Liver Model

RATIONALE AND OBJECTIVES: To investigate the dose-dependency and half-life of decay of the signal reduction by super-paramagnetic iron oxides on three different spin-echo images in a rat model of cirrhosis. METHODS: For normal and cirrhotic liver, signal intensities were measured 15 minutes after injection of Resovist (range, 1-40 mumol Fe/kg) on three different spin-echo images. Subsequently, recovery of signal intensity was monitored up to 2 weeks after injection. RESULTS: The dose-dependency of efficacy was somewhat less at all doses and imaging parameters in cirrhotic liver. However, the submaximal effect was obtained at a dose of 20 mumol Fe/kg, the same as in normal liver. The rate of decay of the efficacy in cirrhotic liver was similar to or faster than that in normal liver. CONCLUSIONS: The dose-dependency and rate of decay of efficacy of Resovist in cirrhosis were similar to those in normal liver, although the efficacy was less in cirrhotic liver and both the dose-dependency and rate of decay of efficacy were dependent on imaging parameters.