Aime Silvio, Calabi Luisella, Biondi Luca, De Miranda Mario, Ghelli Stefano, Paleari Lino, Rebaudengo Cristina, Terreno Enzo
Dipartimento di Chimica IFM, Università di Torino, Via P. Giuria 7, 10125 Torino, Italy.
Magn Reson Med. 2005 Apr;53(4):830-4. doi: 10.1002/mrm.20441.
Iopamidol is one of the most common contrast media used for diagnostic CT-based clinical protocols. Chemically, this molecule contains two pools of mobile protons (amide and alcoholic) that are in exchange with water. At 7.05 T, pH 7.4, and 312 K, the exchange rate of the alcoholic protons is too fast to affect the NMR properties of water protons, whereas the slowly exchanging amide protons induce a T(2)-shortening effect on the "bulk" water signal that is detectable when the concentration is about 12 mM. Moreover, a more pronounced contrast is observed when the amide resonances are saturated by the application of an appropriate RF irradiation field, making iopamidol a potential chemical exchange saturation transfer (CEST) agent whose effect can be detected at a concentration as low as 7 mM (at 7.05 T). The exploitation of the MRI properties of iopamidol could facilitate novel and interesting diagnostic applications for combined MRI and CT studies.
碘帕醇是基于CT诊断临床方案中最常用的造影剂之一。从化学角度来看，该分子含有两组可与水交换的流动质子（酰胺质子和醇质子）。在7.05 T、pH 7.4和312 K条件下，醇质子的交换速率太快，不会影响水质子的核磁共振特性，而交换较慢的酰胺质子会对“整体”水信号产生T2缩短效应，当浓度约为12 mM时可检测到该效应。此外，当通过施加适当的射频照射场使酰胺共振饱和时，会观察到更明显的对比，这使得碘帕醇成为一种潜在的化学交换饱和转移（CEST）剂，其效应在低至7 mM的浓度下（在7.05 T时）即可检测到。对碘帕醇磁共振特性的利用可为磁共振成像和CT联合研究带来新颖且有趣的诊断应用。
