title: Fe(3)O(4)/MnO hybrid nanocrystals as a dual contrast agent for both T(1)- and T(2)-weighted liver MRI.
abstract: To investigate whether it is possible to develop a dual magnetic resonance (MR) contrast agent, Fe(3)O(4)/MnO hybrid nanocrystals were modified to integrate the T(1) and T(2) contrast-enhancing abilities of each compound, and their characteristics as MR contrast agents were investigated. In vitro and in vivo investigations revealed that the Fe(3)O(4)/MnO dumbbell-shaped nanocrystal exerted a negative T(2) contrast effect in its intact form and also gave rise to a positive contrast effect in T(1)-weighted MR imaging by releasing Mn(2+) ions in a low pH environment. This induced organ-specific contrast enhancement for both T(1)- and T(2)-weighted in vivo MR imaging. The usefulness of the Fe(3)O(4)/MnO hybrid nanocrystals as dual contrast agents was evaluated by in vivo MR imaging of an orthotopic xenograft model of human hepatocellular carcinoma (HCC). After injection of the Fe(3)O(4)/MnO hybrid nanocrystals, dual contrast-enhanced MR images that synergistically combined the T(2) and T(1) contrast effects from the Fe(3)O(4) grain and released Mn(2+) ions were obtained by a single acquisition of MR imaging. This facilitated the detection of HCC with a high degree of conspicuity that could not be achieved with any single contrast agent.
authors.affiliation: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine and Center for Molecular and Cellular Imaging, Samsung Biomedical Research Institute, Seoul 135-710, Republic of Korea.
authors.forename: Geun Ho
authors.initials: GH
authors.lastname: Im
authors.forename: Soo Min
authors.initials: SM
authors.lastname: Kim
authors.forename: Dong-Gyu
authors.initials: DG
authors.lastname: Lee
authors.forename: Won Jae
authors.initials: WJ
authors.lastname: Lee
authors.forename: Jung Hee
authors.initials: JH
authors.lastname: Lee
authors.forename: In Su
authors.initials: IS
authors.lastname: Lee
mesh_terms: D000818:Animals; D001921:Brain / Q000473:pathology; D003287:Contrast Media; D005290:Ferric Compounds; D006801:Humans; D008099:Liver / Q000473:pathology*; D008113:Liver Neoplasms / Q000175:diagnosis / Q000473:pathology; D060328:Magnetic Phenomena; D008279:Magnetic Resonance Imaging; D017895:Manganese Compounds; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D053758:Nanoparticles / Q000648:ultrastructure; D010087:Oxides; D023041:Xenograft Model Antitumor Assays
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; D017895:Manganese Compounds; D010087:Oxides; C000499:ferric oxide; C027424:manganese oxide