Pell Gaby S, Briellmann Regula S, Waites Anthony B, Abbott David F, Jackson Graeme D
Brain Research Institute, Melbourne, Heidelberg, Victoria, Australia.
Neuroimage. 2004 Feb;21(2):707-13. doi: 10.1016/j.neuroimage.2003.09.059.
The measurement of the T2 relaxation time (T2 relaxometry) had been established as a reliable tool for the assessment of certain conditions such as temporal lobe epilepsy. The standard procedure for analysis of T2 data uses manually drawn regions of interest (ROIs). This approach is limited by its subjective nature and its restricted scope of investigation within selected regions of the brain. In this study, we introduce a voxel-based analysis approach termed voxel-based relaxometry (VBR). Tissue signal changes were assessed in 19 patients with hippocampal sclerosis (HS) and in 38 healthy controls using (i) conventional ROI-based analysis with several bilateral ROIs and also (ii) the VBR method in which the T2 maps are warped to a stereotactic space, smoothed and statistically compared. Conventional ROI analysis identified the expected T2 increase in the sclerotic hippocampus in all HS patients. Furthermore, 13 of the 19 patients displayed a T2 increase in at least one of the other ROIs. The VBR analysis showed a similar pattern of statistically significant areas of increased T2 within the sclerotic hippocampus. In addition, extrahippocampal areas of increased T2 were apparent including the anterior temporal lobe white matter and the parahippocampal gyrus. The results of the VBR analysis are in agreement with the conventional ROI analysis. The VBR analysis has the advantage of providing an even-handed assessment of T2 differences through the brain. We recommend VBR as an alternative means of relaxometry data analysis that provides an objective assessment of differences between subjects.
T2弛豫时间测量（T2弛豫测定法）已成为评估某些病症（如颞叶癫痫）的可靠工具。分析T2数据的标准程序使用手动绘制的感兴趣区域（ROI）。这种方法受到其主观性以及在大脑选定区域内研究范围受限的限制。在本研究中，我们引入了一种基于体素的分析方法，称为基于体素的弛豫测定法（VBR）。使用（i）基于多个双侧ROI的传统基于ROI的分析以及（ii）将T2图扭曲到立体定向空间、平滑并进行统计比较的VBR方法，对19例海马硬化（HS）患者和38例健康对照的组织信号变化进行了评估。传统的ROI分析在所有HS患者中均发现硬化海马体中预期的T2增加。此外，19例患者中有13例在至少一个其他ROI中显示T2增加。VBR分析显示硬化海马体内T2增加的统计学显著区域呈现出类似模式。此外，T2增加的海马外区域也很明显，包括颞叶前部白质和海马旁回。VBR分析结果与传统的ROI分析一致。VBR分析的优点是能够对整个大脑的T2差异进行公平评估。我们推荐VBR作为弛豫测定数据分析的一种替代方法，它能对受试者之间的差异进行客观评估。
