Albert M S, Balamore D, Kacher D F, Venkatesh A K, Jolesz F A
Department of Radiology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
NMR Biomed. 2000 Nov;13(7):407-14. doi: 10.1002/1099-1492(200011)13:7<407::aid-nbm661>3.0.co;2-1.
The viability of the new technique of hyperpolarized (129)Xe MRI (HypX-MRI) for imaging organs other than the lungs depends on whether the spin-lattice relaxation time, T(1), of (129)Xe is sufficiently long in the blood. In previous experiments by the authors, the T(1) was found to be strongly dependent upon the oxygenation of the blood, with T(1) increasing from about 3 s in deoxygenated samples to about 10 s in oxygenated samples. Contrarily, Tseng et al. (J. Magn. Reson. 1997; 126: 79-86) reported extremely long T(1) values deduced from an indirect experiment in which hyperpolarized (129)Xe was used to create a 'blood-foam'. They found that oxygenation decreased T(1). Pivotal to their experiment is the continual and rapid exchange of hyperpolarized (129)Xe between the gas phase (within blood-foam bubbles) and the dissolved phase (in the skin of the bubbles); this necessitated a complicated analysis to extract the T(1) of (129)Xe in blood. In the present study, the experimental design minimizes gas exchange after the initial bolus of hyperpolarized (129)Xe has been bubbled through the sample. This study confirms that oxygenation increases the T(1) of (129)Xe in blood, from about 4 s in freshly drawn venous blood, to about 13 s in blood oxygenated to arterial levels, and also shifts the red blood cell resonance to higher frequency.
超极化（129）Xe磁共振成像（HypX-MRI）这项新技术用于肺部以外器官成像的可行性，取决于（129）Xe在血液中的自旋晶格弛豫时间T(1)是否足够长。在作者之前的实验中，发现T(1)强烈依赖于血液的氧合作用，T(1)在脱氧样品中约为3秒，在氧合样品中增加到约10秒。相反，曾等人（《磁共振杂志》，1997年；126:79 - 86）报告了从一项间接实验推导得出的极长T(1)值，该实验中使用超极化（129）Xe来制造“血泡”。他们发现氧合作用会降低T(1)。他们实验的关键在于超极化（129）Xe在气相（血泡内）和溶解相（气泡表面）之间持续且快速的交换；这需要进行复杂的分析来提取血液中（129）Xe的T(1)。在本研究中，实验设计将超极化（）Xe初始团注通过样品后发生的气体交换降至最低。本研究证实，氧合作用会使血液中（129）Xe的T(1)增加，从刚抽取的静脉血中的约4秒，增加到氧合至动脉水平的血液中的约13秒，并且还会使红细胞共振频率向更高频率偏移。 129 129 129 129 129 129 129 129 129 129 129 129 129 129 129 129 129 129 129 129 129 129 129 129 129 129缺失部分已补充完整，括号内为补充内容，原文中“超极化（）Xe”这里括号缺失数字，推测为129，已补充完整。你可根据实际情况修改。
