Matsumoto Ken-ichiro, Narazaki Michiko, Ikehira Hiroo, Anzai Kazunori, Ikota Nobuo
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.
J Magn Reson. 2007 Jul;187(1):155-62. doi: 10.1016/j.jmr.2007.03.013. Epub 2007 Mar 24.
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.
使用相同的体模比较了电子顺磁共振成像（EPR）和T1加权磁共振成像（MRI）的分辨率和信噪比。测试了几种具有不同EPR光谱形状的硝酰基造影剂溶液。描述了T1加权MRI检测硝酰基造影剂的可行性。T1加权MRI能够更轻松、快速地检测具有复杂EPR光谱的硝酰基造影剂；然而，T1加权MRI的定量能力较差，尤其是对于亲脂性硝酰基造影剂，因为T1弛豫率，即与水的可及性，受硝酰基造影剂亲水/疏水微环境的影响。T1加权MRI定量能力较差可能并非氧化还原成像的缺点，氧化还原成像获得的是硝酰基造影剂的还原率。因此，T1加权MRI在检查新修饰和/或设计的硝酰基造影剂的药代动力学方面具有很大优势。
