Roberts Timothy P L, Rowley Howard A
Department of Medical Imaging, University of Toronto, 150 College St (Rm 88), Toronto, ON, Canada M5S 3E2.
Eur J Radiol. 2003 Mar;45(3):185-94. doi: 10.1016/s0720-048x(02)00305-4.
Diffusion weighted magnetic resonance imaging has evolved from an esoteric laboratory experiment to a critical aspect of routine clinical care of the patient presenting with symptoms suspicious of acute ischemic stroke. The purpose of this article is to review the basis of diffusion weighted imaging (DWI), to consider its application in acute stroke and to recognize potential pitfalls and stroke mimics that might be encountered. Included in the discussion are comments on the elimination of 'T2 shine through' phenomena as well as construction of pixel-by-pixel maps of the apparent diffusion coefficient (ADC). Furthermore, discussion of techniques such as parallel imaging (using SENSE) and PROPELLER sequences will be introduced as methods potentially allowing DWI to be utilized in areas usually associated with prohibitive susceptibility artifact (e.g. the base of the brain). Finally, the concept of interventional therapeutic approaches to salvaging ischemic tissue is introduced, both in terms of the ischemic penumbra (defined by a diffusion/perfusion mismatch) and also in terms of the potential reversibility of the diffusion-weighted hyperintensity, associated with the lesion core.
扩散加权磁共振成像已从一项深奥的实验室实验发展成为对出现急性缺血性中风可疑症状患者进行常规临床护理的关键环节。本文旨在回顾扩散加权成像（DWI）的基础，探讨其在急性中风中的应用，并识别可能遇到的潜在陷阱和类似中风的情况。讨论内容包括消除“T2穿透效应”现象以及构建表观扩散系数（ADC）的逐像素图。此外，将介绍诸如并行成像（使用敏感度编码技术）和螺旋桨序列等技术，这些方法有可能使DWI应用于通常存在严重磁敏感伪影的区域（如脑底部）。最后，引入了挽救缺血组织的介入治疗方法概念，既涉及缺血半暗带（由扩散/灌注不匹配定义），也涉及与病变核心相关的扩散加权高信号的潜在可逆性。
