Modification of nitroxyl contrast agents with multiple spins and their proton T(1) relaxivity.
The purpose of this study is to test the performance of multispin nitroxyl contrast agents in improving the sensitivity of MR detection for nitroxyl contrast agents. The relation between T(1) relaxivity and the number of paramagnetic centers in a molecule was investigated. Compound 1 is a single molecule of methoxycarbonyl-PROXYL (MC-PROXYL). Two and three MC-PROXYL molecules were chemically coupled to obtain Compounds 2 and 3, which have two and three nitroxyl spins in the molecule, respectively. A good linear relation, the slope of which increased depending on the number of nitroxyl spins in the molecule, was obtained between T(1)-weighted (fast low-angle shot) MR image contrast enhancement at 7 T and the concentration of nitroxyl contrast agents. T(1)-weighted MR image contrast enhancement and T(1) relaxivity levels of nitroxyl contrast agents were increased depending on the number of nitroxyl spins in the molecule. Multicoupling nitroxyl molecules can enhance the T(1)-weighted contrast effect while maintaining the quantitative behavior of the molecule for up to three spins.
Radiation Modifier Research Team, Heavy-Ion Radiobiology Research Group, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba 263-8555, Japan. matsumok@nirs.go.jp
Ken-Ichiro
K
Matsumoto
Haruko
H
Yakumaru
Michiko
M
Narazaki
Hidehiko
H
Nakagawa
Kazunori
K
Anzai
Hiroo
H
Ikehira
Nobuo
N
Ikota
D003287:Contrast Media / Q000737:chemistry*; D003497:Cyclic N-Oxides / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D008279:Magnetic Resonance Imaging; D019047:Phantoms, Imaging; D011522:Protons
D003287:Contrast Media; D003497:Cyclic N-Oxides; D011522:Protons; C012517:proxyl nitroxide