Gillis P, Roch A, Brooks R A
Department of Organic Chemistry, Université de Mons-Hainaut, Mons, B-7000,
J Magn Reson. 1999 Apr;137(2):402-7. doi: 10.1006/jmre.1998.1691.
Local field gradients created by paramagnetic entities shorten water proton relaxation times, particularly T2. This "novel" relaxation mechanism, now known as susceptibility-induced relaxation, was described twenty years ago by Gueron, and later extended by others to superparamagnetic particles which have a much larger magnetization. Unfortunately, because of subtle but significant errors, those results are valid only in the strict zero-field limit. These errors are corrected in the present article, and new versions of the relaxation equations are presented. The correction is shown to be significant, not only for transverse and longitudinal relaxation in aqueous superparamagnetic colloids, where the "Gueron" effect is known to be important, but even in some cases for transverse paramagnetic relaxation.
顺磁性物质产生的局部场梯度会缩短水质子的弛豫时间，尤其是T2。这种“新型”弛豫机制，现在被称为磁化率诱导弛豫，二十年前由盖伦描述，后来其他人将其扩展到具有更大磁化强度的超顺磁性粒子。不幸的是，由于一些细微但显著的误差，那些结果仅在严格的零场极限下才有效。本文对这些误差进行了修正，并给出了弛豫方程的新版本。结果表明，这种修正不仅对水性超顺磁性胶体中的横向和纵向弛豫（已知“盖伦”效应在其中很重要）具有显著意义，甚至在某些情况下对横向顺磁性弛豫也有显著意义。
