BULK MAGNETIC-SUSCEPTIBILITY SHIFTS IN NMR-STUDIES OF COMPARTMENTALIZED SAMPLES - USE OF PARAMAGNETIC REAGENTS
BULK MAGNETIC-SUSCEPTIBILITY SHIFTS IN NMR-STUDIES OF COMPARTMENTALIZED SAMPLES - USE OF PARAMAGNETIC REAGENTS
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DOI：
10.1002/mrm.1910130207
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发表时间：
1990-02-01
影响因子：
3.3
通讯作者：
SPRINGER, CS
中科院分区：
文献类型：
--
作者：
CHU, SCK;XU, Y;SPRINGER, CS
在活体核磁共振、磁共振波谱和磁共振成像中，顺磁性化合物引起的核磁共振频率的体磁化率(BMS)漂移是非常重要的。然而，由于它是一个相当复杂的现象，它一直是文学中许多误解的来源。我们已经重新编写和组织了BMS转变的理论。这包括考虑到局部易感性的重要影响。我们对体模样本进行了实验，以说明所涉及的原理。我们的幻影由毛细血管和同轴圆柱体组成。它们模拟了血管与磁场平行和垂直的情况，以及它们周围的间隙。在我们的大多数实验中，顺磁性化合物是几种不同的阳离子共振超精细位移试剂之一。选择这些指标是为了涵盖它们所产生的变化的一系列潜力，无论是大小还是符号。然而，我们也使用了一种试剂，该试剂不能诱导超精细位移，因此只能引起BMS位移。虽然我们在本文中只报道了23Na光谱，但后一种样品模拟了在使用超精细位移试剂进行阳离子转移的实验中观察到水1H共振的情况。最近在文献中报道了许多这样的调查。本文所考虑的原理使我们能够对过去几年发表的几个实验的结果提供新的解释。
The bulk magnetic susceptibility (BMS) shift of a nuclear resonance frequency caused by a paramagnetic compound is of importance inin vivoNMR, both magnetic resonance spectroscopy and magnetic resonance imaging. However, since it is a rather complicated phenomenon, it has been the source of many misinterpretations in the literature. We have reworked and organized the theory of the BMS shift. This includes accounting for the important effects of local susceptibility. We have conducted experiments on phantom samples in order to illustrate the principles involved. Our phantoms consist of capillaries and coaxial cylinders. They simulate the situations of blood vessels oriented parallel and perpendicular to the magnetic field and the interstitial spaces surrounding them. In most of our experiments, the paramagnetic compound was one of several different hyperfine shift reagents for cation resonances. These were chosen to cover a range of potencies, in both magnitude and sign, of the shifts they produce. However, we also used a reagent which was incapable of inducing a hyperfine shift and thus could cause only a BMS shift. Although we report only23Na spectra in this paper, the latter samples simulate the cases where one observes the water1H resonance in experiments employing hyperfine shift reagents for cations. There have been a number of such investigations recently reported in the literature. The principles considered in this paper allow us to offer new interpretations for the results of several experiments published in the last few years.