Buxton R B, Frank L R, Wong E C, Siewert B, Warach S, Edelman R R
Department of Radiology, University of San Diego, California, USA.
Magn Reson Med. 1998 Sep;40(3):383-96. doi: 10.1002/mrm.1910400308.
Recently, several implementations of arterial spin labeling (ASL) techniques have been developed for producing MRI images sensitive to local tissue perfusion. For quantitation of perfusion, both pulsed and continuous labeling methods potentially suffer from a number of systematic errors. In this study, a general kinetic model for the ASL signal is described that can be used to assess these errors. With appropriate assumptions, the general model reduces to models that have been used previously to analyze ASL data, but the general model also provides a way to analyze the errors that result if these assumptions are not accurate. The model was used for an initial assessment of systematic errors due to the effects of variable transit delays from the tagging band to the imaging voxel, the effects of capillary/tissue exchange of water on the relaxation of the tag, and the effects of incomplete water extraction. In preliminary experiments with a human subject, the model provided a good description of pulsed ASL data during a simple sensorimotor activation task.
最近，已开发出几种动脉自旋标记（ASL）技术的实施方案，用于生成对局部组织灌注敏感的MRI图像。对于灌注定量，脉冲标记和连续标记方法都可能存在一些系统误差。在本研究中，描述了一种用于ASL信号的通用动力学模型，该模型可用于评估这些误差。在适当的假设下，通用模型简化为先前用于分析ASL数据的模型，但通用模型还提供了一种方法来分析如果这些假设不准确所导致的误差。该模型用于初步评估由于从标记带至成像体素的可变传输延迟效应、水在毛细血管/组织间交换对标记弛豫的影响以及不完全水提取的影响而产生的系统误差。在对一名人类受试者的初步实验中，该模型对简单感觉运动激活任务期间的脉冲ASL数据提供了很好的描述。
