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 superparamagnetic iron oxides on three different spin-echo images in a rat model of cirrhosis. METHODS. For normal and cirrhotic liver, signal intensities were measured 1 5 minutes after injection of Resovist (range, 1-40 mu mol Fe/kg) on three d ifferent spin-echo images. Subsequently, recovery of signal intensity was m onitored 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 mu mol Fe/kg, the same as in normal liver. The rat e 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 w as less in cirrhotic liver and both the dose-dependency and rate of decay o f efficacy were dependent on imaging parameters.