Xu Junzhong, Does Mark D, Gore John C
Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232-2310, USA.
J Magn Reson. 2009 Oct;200(2):189-97. doi: 10.1016/j.jmr.2009.06.022. Epub 2009 Jul 3.
The signals recorded by diffusion-weighted magnetic resonance imaging (DWI) are dependent on the micro-structural properties of biological tissues, so it is possible to obtain quantitative structural information non-invasively from such measurements. Oscillating gradient spin echo (OGSE) methods have the ability to probe the behavior of water diffusion over different time scales and the potential to detect variations in intracellular structure. To assist in the interpretation of OGSE data, analytical expressions have been derived for diffusion-weighted signals with OGSE methods for restricted diffusion in some typical structures, including parallel planes, cylinders and spheres, using the theory of temporal diffusion spectroscopy. These analytical predictions have been confirmed with computer simulations. These expressions suggest how OGSE signals from biological tissues should be analyzed to characterize tissue microstructure, including how to estimate cell nuclear sizes. This approach provides a model to interpret diffusion data obtained from OGSE measurements that can be used for applications such as monitoring tumor response to treatment in vivo.
扩散加权磁共振成像（DWI）记录的信号取决于生物组织的微观结构特性，因此可以通过此类测量非侵入性地获取定量结构信息。振荡梯度自旋回波（OGSE）方法有能力探测不同时间尺度上的水扩散行为，并具有检测细胞内结构变化的潜力。为了辅助解释OGSE数据，利用时间扩散光谱理论，针对一些典型结构（包括平行平面、圆柱体和球体）中的受限扩散，推导了OGSE方法用于扩散加权信号的解析表达式。这些解析预测已通过计算机模拟得到证实。这些表达式表明了应如何分析来自生物组织的OGSE信号以表征组织微观结构，包括如何估计细胞核大小。这种方法提供了一个模型来解释从OGSE测量获得的扩散数据，可用于诸如监测体内肿瘤对治疗的反应等应用。
