PHYSIOLOGICAL MR STUDIES USING HYPERPOLARIZED 129XE

惰性气体氙是一种安全有效的全身麻醉剂。 迅速 通过肺部吸收到血液中，它集中在脂质中， 与血流相关的时间依赖性丰富的组织。 一个主要 一个自旋为1/2的原子核，具有显著的化学位移 对货车德瓦耳斯环境敏感（范围，300 ppm）。 T和T 值对O2浓度和其他因素非常敏感。 的 关键的一点是，在给药之前， 超极化，105-106倍，通过与光泵浦的自旋交换 铷：它的核磁共振信号强度（以及时间和空间分辨率） 在20 mM下，将与80-100 mM下的组织水质子的浓度相当 M：这种独特的性质，以及它的明显不同， 与H2O相比，在（a）细胞和组织区室化，（B） 和亚细胞交换动力学，将提供一个新的足够的数量， 超极化Ce（Xet）。 成像程序，联合 光谱和成像（CIS），以及局部T和 T概率分布（松弛法），在我们的 H和Na的实验室，将适用于新的模式。 参数 用于确定和优化时间和空间分辨率， 用特氟龙模型来做Xegas CSI的参数将 使用水-辛醇-气体体模获得。 中的总体行为 小鼠将在几个大的体素-肺气隙，整个 大脑和大块肌肉 外汇交易的动态， 在细胞和亚细胞水平上的区室化和松弛 将从化学位移，线形， T和T_2在分级神经系统模型非影像学研究中的应用 复杂性，对于一系列O2浓度。 运输的动力学， 分布，和寿命的小鼠和大鼠体内将是 在其他主要器官和外周组织中进行了研究。 的 麻醉剂的药代动力学行为本身是重要的。 最后，将研究三种众所周知的小鼠和大鼠范例（a） 缺氧、远视和高碳酸血症（过量二氧化碳）对血流的影响 （B）刺激个体的作用 神秘的触须（面部胡须）在“桶场”地区的 小鼠大脑的躯体感觉区域;（c）对脑电成像的影响 （与H成像和T的CONTIN分析相关） 将2 × 10 KHT肉瘤细胞注射到小鼠体内后的肿瘤 腓肠肌，以及转移性腺癌的类似研究 和脑胶质瘤

The noble gas xenon is a safe and effective general anesthetic. Rapidly absorbed via the lung into the blood-stream, it concentrates in lipid- rich tissue with a time-dependence related to blood flow. A major isotope, Xe, has a spin 1/2 nucleus with a chemical shift remarkably sensitive to van de Waals environment (range, 300 ppm). Its T and T values are quite sensitive to O2 concentration and other factors. The crucial point is that, prior to administration, Xe can readily be hyperpolarized, 105-106 fold by spin exchange with optically pumped rubidium: its NMR signal strength (and thus time and space resolution) at 20 mM, would be comparable to that of tissue water proton at 80-100 M: This unique property of Xe, as well as its distinctly different behavior compared to H2O in(a) cell and tissue compartmentalization, (b) and subcellular exchange kinetics, will provide a new adequate quantities of hyperpolarized Ce (Xet). Procedures for imaging, Combined Spectroscopy and Imaging (CIS), and image-guided analysis of local T and T probability distributions (Relaxography), well-established in our laboratory for H and Na, will be applied to the new modality. Parameters for determining and optimizing time and space resolution will be obtained using pattern-drilled Teflon phantoms for Xegas. Parameters for CSI will be obtained using a water-octanol-gas phantom. Overall behavior in the mouse will assayed in several large voxels-the lung gas space, the whole brain, and a large muscle. The dynamics of Xe exchange, compartmentalization and relaxation at the cellular and subcellular level will be determined from the behavior of the chemical shift, line shape, T and T2 in nonimaging studies of model systems of hierachiacal complexity, for a range of O2 concentrations. The dynamics of transport, distribution, and lifetime of Xe in the mouse and rat in vivo will be investigated in other major organs, and peripheral tissues. The pharmacokinetics behavior of an anesthetic is important in its own right. Finally, three well-known mouse and rat paradigms will be studied (a) effects of hypoxia, hyperopia and hypercapnia (excess CO2) on blood flow and Xe in brain and elsewhere; (b) effects of stimulating individual mystical vibrissae (facial whiskers) on Xe in the 'barrel field' area of the somatosensory region of the mouse brain; (c) effect on Xe images (correlated with H imaging and CONTIN analysis of T) of development of tumors following injection of 2X10 KHT sarcoma cells into the mouse gastrocnemius, and similar studies with a metastasizing adenocarcinoma and a brain glioma.