Investigation of Early Liver Radiation Injury Using Resovist-Enhanced MRI at 3T

The aim of this study was to investigate the rat liver injury caused by radiation using contrast enhanced magnetic resonance imaging (MRI) at 3T. The contrast agent used was Resovist, a kind of commercialized superparamagnetic iron oxide (SPIO). SPIO particles can be macrophaged by Kupffer cells after intravenous injection. The macrophaged SPIO particles make the MR signal decrease because of the susceptibility effect. When liver has injury caused by radiation, the macrophage function of Kupffer cells decreases. Once the Kupffer cells malfunction, the MR signal of irradiated liver decreases less than normal liver after SPIO administration. Therefore, liver radiation injury can be detected. The MR signal enhancement varies with the magnetic field strength, pulse sequences, injected SPIO doses and duration after SPIO injection. Three to four days after rat´s liver was irradiated with 30 Gy X-ray, the MR signal enhancement of rat liver at 3T after 80 μmol/kg body weight Resovist injection was investigated in this study.