Rationale And Objectives: Comparison of two different ultrasmall superparamagnetic iron oxide (USPIO) particles in terms of their intracellular cell-labeling properties of macrophages and subsequent visualization by MR imaging.
Materials And Methods: Cultures containing the macrophage cell line P-388D1 were incubated with a neutral carboxydextran-coated USPIO preparation (DDM 43/34/103) or an acidic citrate-coated USPIO (VSOP-C125). Experiments were performed in which incubation concentration and duration were varied and phagocytosis and pinocytosis suppressed by specific inhibitors.