Ischaemia is a condition in which blood flow either drops to zero or proceeds at severely decreased levels that cannot supply sufficient oxidizable substrates to maintain energy metabolism in vivo. Brain, a highly oxidative organ, is particularly susceptible to ischaemia. Ischaemia leads to loss of consciousness in seconds and, if prolonged, permanent tissue damage is inevitable. Ischaemia primarily results in a collapse of cerebral energy state, followed by a series of subtle changes in anaerobic metabolism, ion and water homeostasis that eventually initiate destructive internal and external processes in brain tissue. (31)P and (1)H NMR spectroscopy were initially used to evaluate anaerobic metabolism in brain. However, since the early 1990s (1)H Magnetic Resonance Imaging (MRI), exploiting the nuclear magnetism of tissue water, has become the key method for assessment of ischaemic brain tissue. This article summarises multi-parametric (1)H MRI work that has exploited diffusion, relaxation and magnetisation transfer as 'contrasts' to image ischaemic brain in preclinical models for the first few hours, with a view to assessing evolution of ischaemia and tissue viability in a non-invasive manner.

中文翻译：

---

急性实验性脑缺血的多参数磁共振成像

缺血是一种血流量下降到零或以严重降低的水平进行的状况，无法提供足够的可氧化底物来维持体内能量代谢。大脑是一个高度氧化的器官，特别容易缺血。缺血会在几秒钟内导致意识丧失，如果时间延长，永久性组织损伤是不可避免的。缺血主要导致大脑能量状态的崩溃，随后是厌氧代谢、离子和水稳态的一系列细微变化，最终引发脑组织中破坏性的内部和外部过程。(31)P 和 (1)H NMR 光谱最初用于评估大脑中的厌氧代谢。然而，自 1990 年代初期 (1)H 磁共振成像 (MRI) 以来，利用组织水的核磁性，已成为评估缺血脑组织的关键方法。本文总结了多参数 (1)H MRI 工作，该工作利用扩散、弛豫和磁化转移作为前几个小时临床前模型中缺血脑成像的“对比”，以评估缺血的演变和组织活力。一种非侵入性的方式。