FUNCTIONAL IMAGING OF BRAIN

该项目的目标是开发磁共振成像技术，用于 监测大脑功能。这项工作是通过开发一种 依赖于动脉自旋标记的磁共振灌注成像技术 内源性水作为血流示踪剂。五年来， 这类核磁共振灌注成像技术已经被证实是有用的 用于测量休息时大脑的局部血流量，任务 激活，并在人类和动物模型中处于疾病状态。 这项技术对局部血流进行了定量测量。 利用MRI的空间和时间分辨率，在各种 纸巾。这类技术的进一步发展正在进行中 与旨在扩展战略的实验一起进行 动脉自旋标记，利用标记水作为探针 将水提取到组织中，并使其成为常规，以快速获得 老鼠大脑中的三维图像。此外，当 将这类灌注成像技术应用于大脑，应该 对脑图研究很有用，尤其是表格A 是对大胆技巧的补充。目前，所有的功能性核磁共振 监测神经元激活的血流动力学后果的技术 而不是神经元活动的直接影响。连续不断的 导致神经元激活的事件是释放 神经递质，去极化，钙内流，释放 神经递质，等等。血流动力学的变化是作为一种反应发生的 以维持大脑的动态平衡。一种更直接的MRI测量 神经元激活可能非常有用。初步结果 提示Mn2~可能是一种优良的探头造影剂 在动物模型中，钙内流与神经元活动有关。在……里面 此外，Mn2~似乎曾经作为顺行神经元示踪剂 它进入神经元。这两个令人兴奋的结果都开启了 将功能性磁共振技术扩展到大脑的可能性。

The objectives of this project are to develop MRI techniques for monitoring of brain function. This work was begun by development of a perfusion MRI technique that relies on arterial spin labeling of endogenous water as a perfusion tracer. Over the past five years, this class of perfusion MRI technique has been established as useful for measuring regional blood flow in the brain during rest, task activation, and in disease states in both humans and animal models. This technique makes quantitative measurements of regional blood flow with the spatial and temporal resolution of MRI in a variety of tissues. Further development of this class of techniques is being carried out with experiments designed to extend strategies for arterial spin labeling, make use of the labeled water as a probe of water extraction into tissue, and make it routine to acquire rapid three dimensional images in the mouse brain. Furthermore, when applied to the brain, this class of perfusion imaging technique should be useful for brain mapping studies and, in particular, forms a complement to BOLD techniques. Presently, all functional MRI techniques monitor the hemodynamic consequences of neuronal activation rather than a direct effect of neuronal activity. The cascade of events that lead to neuronal activation are release of neurotransmitter, depolarization, influx of calcium, release of neurotransmitter, and so on. Hemodynamic changes occur as a response of the brain to maintain homeostasis. A more direct MRI measure of neuronal activation might be very useful. Preliminary results indicate that Mn2~ might be an excellent contrast agent to probe calcium influx associated with neuronal activity in animal models. In addition, Mn2~ appears to act as an anterograde neuronal tracer once it enters neurons. Both of these exciting results open the possibility of extending functional MR techniques for the brain.