title: Comparisons of EPR imaging and T1-weighted MRI for efficient imaging of nitroxyl contrast agents.
abstract: The resolution and signal to noise ratio of EPR imaging and T(1)-weighted MRI were compared using an identical phantom. Several solutions of nitroxyl contrast agents with different EPR spectral shapes were tested. The feasibility of T(1)-weighted MRI to detect nitroxyl contrast agents was described. T(1)-weighted MRI can detect nitroxyl contrast agents with a complicated EPR spectrum easier and quicker; however, T(1)-weighted MRI has less quantitative ability especially for lipophilic nitroxyl contrast agents, because T(1)-relaxivity, i.e. accessibility to water, is affected by the hydrophilic/hydrophobic micro-environment of a nitroxyl contrast agent. The less quantitative ability of T(1)-weighted MRI may not be a disadvantage of redox imaging, which obtains reduction rate of a nitroxyl contrast. Therefore, T(1)-weighted MRI has a great advantage to check the pharmacokinetics of newly modified and/or designed nitroxyl contrast agents.
authors: Radiation Modifier Research Team, Heavy-Ion Radiobiology Research Group, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi, Chiba 263-8555, Japan. matsumok@nirs.go.jp
authors: Ken-ichiro
authors: K
authors: Matsumoto
authors: Michiko
authors: M
authors: Narazaki
authors: Hiroo
authors: H
authors: Ikehira
authors: Kazunori
authors: K
authors: Anzai
authors: Nobuo
authors: N
authors: Ikota
mesh_terms: D016880:Anisotropy; D002021:Buffers; D003287:Contrast Media / Q000737:chemistry*; D003497:Cyclic N-Oxides / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D007093:Imidazoles / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D009589:Nitrogen Oxides / Q000737:chemistry*; D019047:Phantoms, Imaging; D011759:Pyrrolidines / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry
chemical_list: D002021:Buffers; D003287:Contrast Media; D003497:Cyclic N-Oxides; D007093:Imidazoles; D009589:Nitrogen Oxides; D011759:Pyrrolidines; C079391:2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide; D012710:Serum Albumin, Bovine; D012967:Sodium Dodecyl Sulfate; C077426:3-carbamoyl-2,2,5,5-tetramethyl-1-pyrrolidinyl-N-oxyl; C039900:nitroxyl