MR contrast material for vascular enhancement: Value of superparamagnetic iron oxide

OBJECTIVE. The purposes of this study were to quantify abdominal vascular enhancement and to prove the feasibility of iron oxide-enhanced MR angiography in humans using three doses of superparamagnetic iron oxide agent AMI 227. SUBJECTS AND METHODS. Sixteen patients randomly received either 0.8, 1.1, or 1.7 mg Fe/kg of ultrasmall superparamagnetic iron oxide agent AMI 227. T1-weighted breath-hold gradient-echo images were obtained before and 45 min after IV administration of AMI 227. Signal intensity was measured in the aorta, the inferior vena cava, the portal vein, and muscle on unenhanced and contrast-enhanced images. Signal-to-noise ratios and enhancement [(SNR after contrast-SNR before contrast) / SNR before contrast] were calculated. Vessels were visually graded before and after administration of AMI 227. RESULTS. All vessels showed statistically significant enhancement 45 min. after administration of AMI 227 by both qualitative and quantitative measures (p < .001). There was no significant increase in noise or signal intensity of muscle after contrast material was administered. The amount of enhancement was not statistically significantly different among the three doses. CONCLUSION. AMI 227, which is currently in phase III clinical trials, demonstrates significant vascular enhancement and may prove useful as an MR angiographic contrast agent.