The role of voxel aspect ratio in determining apparent vascular phase behavior in susceptibility weighted imaging
The role of voxel aspect ratio in determining apparent vascular phase behavior in susceptibility weighted imaging
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DOI：
10.1016/j.mri.2005.10.030
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发表时间：
2006-02-01
影响因子：
2.5
通讯作者：
Haacke, EM
中科院分区：
文献类型：
--
作者：
Xu, YB;Haacke, EM
磁化率加权成像（SWI）利用视相衬来提高幅值图像的噪比（CNR）。理论上，视相位取决于静脉血和实质占据同一体素时的纵横比。为了证明外场对脉体的最大预期影响，我们将脉体建模为垂直于主磁场的无限长圆柱体。结果表明，图像中体素的视相位是分辨率、血管尺寸和在较小程度上影响图像质量的函数。体素内的容器中心。模拟解释了为什么负相位掩模在SWI中起作用[Haacke EM， Xu Y, 14 Cheng YN, Reichenbach JR，磁化率加权成像，磁共振医学2004；[52:612-618]在横向采集的高分辨率图像的处理，尽管垂直于主场的船只的预期正相位行为。从模拟中预测的相行为与从人脑数据集中观察到的相行为很好地吻合。(C) 2006爱思唯尔公司版权所有。
Susceptibility weighted imaging (SWI) uses apparent phase contrast to enhance the contrast-to-noise ratio (CNR) in the magnitude image. In theory, the apparent phase will depend on the aspect ratio when both venous blood and parenchyma occupy the same voxel. To demonstrate the maximal expected effect of the external field from a vein, we model the vein as an infinitely long cylinder perpendicular to the main magnetic field. The results show that the apparent phase of a voxel in the image is a function of resolution, vessel size and, to a lesser degree.. vessel center within the voxel. The simulations explain why a negative-phase mask has worked in SWI [Haacke EM, Xu Y, 14 Cheng YN, Reichenbach JR, Susceptibility Weighted Imaging, Magn Reson Med 2004;52:612-618] processing of high-resolution images collected in the transverse direction, despite the expected positive-phase behavior for vessels perpendicular to the main field. The predicted phase behavior from the simulations is in good agreement with that observed from human brain datasets. (C) 2006 Elsevier Inc. All rights reserved.