Gore J C, Brown M S, Zhong J, Mueller K F, Good W
Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut 06510.
Magn Reson Med. 1989 Mar;9(3):325-32. doi: 10.1002/mrm.1910090304.
The NMR relaxation rates of a class of hydrated polymers (hydrogels) have been investigated over a wide range of frequencies (0.01 to 60 MHz) and compositions. The gels comprise long chains of polytetramethylene oxide diol crosslinked by copolymers of dimethylacrylamide and methylmethacrylate. The longitudinal relaxation rate dispersion curves of these materials are very similar to those shown by human tissues and they can be altered in flexible fashion by changing the polymer content. By substitution of the water by deuterium oxide, the contribution of intermolecular cross-relaxation effects has been shown to account for two-thirds the total water relaxation rate. With their close similarity to tissue relaxation behavior, hydrogels of differing compositions are particularly well-suited to MRI phantoms and test objects.
一类水合聚合物（水凝胶）的核磁共振弛豫率已在很宽的频率范围（0.01至60兆赫）和组成范围内进行了研究。这些凝胶由聚四亚甲基醚二醇的长链组成，通过二甲基丙烯酰胺和甲基丙烯酸甲酯的共聚物交联。这些材料的纵向弛豫率色散曲线与人体组织的曲线非常相似，并且可以通过改变聚合物含量以灵活的方式进行改变。用重水替代水后，分子间交叉弛豫效应的贡献已被证明占总水弛豫率的三分之二。由于它们与组织弛豫行为非常相似，不同组成的水凝胶特别适合用于磁共振成像体模和测试对象。
