Dose investigation of superparamagnetic iron oxide (SPIO) SH U 555 A in liver MR imaging

SH U 555 A, a new superparamagnetic iron oxide(SPIO)contrast agent for liver MR imaging, was investigated in terms of safety and efficacy. Eighty-four patients with suspected malignant liver tumor were randomly allocated to two groups: the L dose group (8 μmol Fe/kg) and H dose group (12 μmol Fe/kg). Efficacy was qualitatively evaluated through blinded reading of the MR images. Assessment of the images revealed no consistent differences between the L and H dose groups. During the 3- to 4-day observation period, a total of 16 adverse events were observed in 11 patients: 8 patients in the L dose group and 3 patients in the H dose group. Nasal bleeding occurred in 2 of these cases in the H dose group 2 and 4 days, respectively, after injection. Although patients in the H dose group showed a significantly larger transient decrease in Coagulation Factor XI at 4-6 hr post-injection (p. i.) than patients in the L dose group, analysis of covariance revealed an estimated 6.5% difference. There was no prolongation of APTT or change in Factor XI at 72-96 hr p. i. Because there were no clinically significant differences between the L and H doses, both were considered to be safe and effective.