Li T Q, Chen Z G, Hindmarsh T
Karolinska MR Research Center, Stockholm, Sweden.
Acta Radiol. 1998 Sep;39(5):460-73. doi: 10.1080/02841859809172209.
Diffusion-weighted MR imaging has been used in studies on experimental animal models and on patients with acute cerebral ischemia. Compared with CT and conventional MR techniques, diffusion-weighted imaging can provide earlier and more precise detection of the location and the extent of an ischemic lesion during the critical first few hours after the onset of stroke. Quantitative apparent diffusion coefficient (ADC) mapping of the brain water can also be carried out by recording a series of diffusion-weighted images with different amplitudes of the displacement encoding gradients. ADC maps can provide important information about the extra- and intracellular water homeostasis. ADC reduction of the tissue water is one of the early signals of the pathophysiological cascade resulting from ischemic tissue injury. Diffusion MR imaging has become a valuable tool in stroke research. It may also prove a valuable tool in monitoring the efficiency of therapeutic effects in stroke patients. It is our intention to provide an overview of the recent development in this area with emphasis on the diffusion-weighted MR techniques, and to discuss the possible underlying biophysical mechanisms responsible for the contrast of diffusion-weighted imaging.
扩散加权磁共振成像已用于实验动物模型和急性脑缺血患者的研究。与CT和传统磁共振技术相比，扩散加权成像能够在中风发作后的关键最初几个小时内，更早、更精确地检测出缺血性病变的位置和范围。通过记录一系列具有不同幅度位移编码梯度的扩散加权图像，还可以对脑水进行定量表观扩散系数（ADC）映射。ADC图可以提供有关细胞外和细胞内水平衡的重要信息。组织水的ADC降低是缺血性组织损伤导致的病理生理级联反应的早期信号之一。扩散磁共振成像已成为中风研究中的一种有价值的工具。它也可能被证明是监测中风患者治疗效果的一种有价值的工具。我们打算概述该领域的最新进展，重点是扩散加权磁共振技术，并讨论导致扩散加权成像对比度的可能潜在生物物理机制。
