The purpose of this study is to evaluate the efficacy of glucose transporter protein 1 (GLUT1) antibody-conjugated iron oxide nanoparticles (Fe3O4 NPs) as magnetic resonance imaging (MRI) molecular imaging agents for differentiating infantile hemangioma from vascular malformation in the hemangioma animal model. The conjugation of Fe3O4 NPs with anti-GLUT1 antibodies leads to a significantly increased uptake of NPs by human umbilical vein endothelial cells. MRI imaging following the intravenous injection of GLUT1 antibody-Fe3O4 NPs yielded a significantly lower signal intensity than did unconjugated Fe3O4 NPs. Upon histological examination of the GLUT1 antibody-Fe3O4 NPs, Prussian blue-stained NPs were identified in CD31-positive endothelial cells of hemangioma. In contrast, when treated with unconjugated Fe3O4 NPs, Prussian blue-stained NPs were found in macrophages rather than in endothelial cells. GLUT1 antibody conjugation can effectively target the injected Fe3O4 NPs to GLUT1-positive tumor cells in infantile hemangioma. From the Clinical Editor: This study evaluates the efficacy of glucose transporter protein 1 antibody-conjugated iron oxide nanoparticles as MRI molecular imaging agents for differentiating infantile hemangioma from vascular malformation. Results demonstrate that CD-31 positive endothelial cells are targeted by this complex, which largely accumulates in macrophages resulting in significant MRI signal changes compared to using iron oxide alone. (C) 2015 Elsevier Inc. All rights reserved.