Voxel-Based Iterative Sensitivity (VBIS) analysis: Methods and a validation of intensity scaling for T2-weighted imaging of hippocampal sclerosis
Voxel-Based Iterative Sensitivity (VBIS) analysis: Methods and a validation of intensity scaling for T2-weighted imaging of hippocampal sclerosis
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DOI：
10.1016/j.neuroimage.2008.09.055
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发表时间：
2009-02-01
期刊：
影响因子：
5.7
通讯作者：
Jackson, Graeme D.
中科院分区：
文献类型：
--
作者：
Abbott, David F.;Pell, Gaby S.;Jackson, Graeme D.
脑内的异常通常在MRI上表现为形状（形态测量学）或组织性质（信号强度）的变化。基于体素的形态测量（VBM）是一种定量评估全脑形态变化的方法。基于体素的弛豫测量法（VBR）直接评估T2弛豫时间定量图中的信号强度变化，但这需要专门的多回波采集序列，而这些序列通常在临床站点不可用。本文介绍并评估了一种客观的基于体素的统计方法，用于评价常规采集的定性图像组中的信号强度。我们称之为基于体素的迭代灵敏度（VBIS）分析的方法。它自适应地优化图像的相对全局缩放，以最大限度地提高对区域效应的敏感性。我们应用并验证了T2加权图像的人脑的分析方法。为了验证该方法，它直接与VBR相比，提取T2加权图像的一个单一的回声从多回波T2弛豫采集一组24例左半球海马硬化症和97名健康对照。VBIS-T2可检测到患者的预期信号异常，证实了该技术的可行性。这为在MRI扫描仪上已经和正在采集的大量T2加权图像数据上使用基于体素的分析方法打开了大门。当没有定量模式时，VBIS可以是量化组间差异的有效方法。我们希望该方法也可以帮助定量分析其他定性方式，如T1加权MRI，SPECT和CT。(C)2008年爱思唯尔公司All rights reserved.
Abnormalities in the brain generally manifest on MRI as changes in shape (morphometry) or changes in the nature of the tissue (signal intensity). Voxel Based Morphometry (VBM) is a whole brain quantitative way of assessing morphometric changes. Voxel Based Relaxometry (VBR) directly assesses signal intensity changes in quantitative maps of T2 relaxation time, but this requires specialised multiple-echo acquisition sequences that are not usually available at clinical sites. This paper introduces and assesses an objective voxel-based statistical method for evaluation of signal intensity in groups of routinely acquired qualitative images. We call the method Voxel-Based Iterative Sensitivity (VBIS) analysis. It adaptively optimises the relative global scaling of images to maximise sensitivity to regional effects. We apply and validate the method of analysis for T2-weighted images of the human brain. To validate the method, it was directly compared with VBR by extracting T2-weighted images of a single echo from multi-echo T2 relaxometry acquisitions from a group of 24 patients with left hemisphere hippocampal sclerosis and 97 healthy controls. Expected signal abnormalities in the patients were detectable with VBIS-T2, confirming the feasibility of the technique. This opens the door to the use of a voxel-based analysis approach on the vast amount of T2-weighted image data that has been and is being acquired on MRI scanners. When a quantitative modality is not available, VBIS can be an effective way to quantify differences between groups. We expect the method could also assist quantitative analysis of other qualitative modalities such as T1-weighted MRI, SPECT and CT. (C) 2008 Elsevier Inc. All rights reserved.