A superparamagnetic iron oxide nanoparticle coated with a low molecular weight semi-synthetic carbohydrate, polyglucose sorbitol carboxymethyl ether, with potential anti-anemic and imaging properties. After intravenous administration, ferumoxytol replaces iron stores with fewer side effects compared to the use of oral iron. In addition, this agent generates T1 relaxation, producing a magnetic field and enhancing T2 relaxation, thereby darkening contrast media-containing structures in magnetic resonance imaging (MRI). Due to small particle size, ferumoxytol remains in the intravasculature for a prolonged period and so may be used as a blood pool agent.