A novel phantom and method for comprehensive 3-dimensional measurement and correction of geometric distortion in magnetic resonance imaging
A novel phantom and method for comprehensive 3-dimensional measurement and correction of geometric distortion in magnetic resonance imaging
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DOI：
10.1016/j.mri.2004.01.008
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发表时间：
2004-05-01
影响因子：
2.5
通讯作者：
Cowin, G
中科院分区：
文献类型：
--
作者：
Wang, DM;Doddrell, DM;Cowin, G
描述了一种可用于映射磁共振成像（MRI）中几何失真的体模。该体模在三维（3D）空间中提供密集分布的控制点阵列。这些点形成了综合测量方法的基础，以校正主要由梯度场非线性和磁场不均匀性引起的MR图像中的几何失真。该体模的设计基于可以使用三个正交平面定义空间中的一个点的概念。这种新颖的设计方法允许尽可能多的控制点。采用这种新颖的设计，已经开发出一种高精度的方法，使控制点的位置被测量到亚体素精度。本文中描述的体模被构造成适合MRI扫描仪的体线圈（体模的外部尺寸为：310 mm x 310 mm x 310 mm），并且它包含10，830个控制点。对于该体模，控制点的测量坐标的平均误差在0.1 mm或更小的量级上，其小于体模图像的体素尺寸的十分之一。计算的三维失真图，即，图像位置和控制点的真实位置之间的差异然后可以用于补偿完全图像恢复的几何失真。预计这种新方法将对MRI在临床和研究环境中的适用性产生影响。特别是在高度要求几何精度的领域，例如在MR神经成像中。(C)2004年爱思唯尔公司All rights reserved.
A phantom that can be used for mapping geometric distortion in magnetic resonance imaging (MRI) is described. This phantom provides an array of densely distributed control points in three-dimensional (3D) space. These points form the basis of a comprehensive measurement method to correct for geometric distortion in MR images arising principally from gradient field non-linearity and magnet field inhomogeneity. The phantom was designed based on the concept that a point in space can be defined using three orthogonal planes. This novel design approach allows for as many control points as desired. Employing this novel design, a highly accurate method has been developed that enables the positions of the control points to be measured to sub-voxel accuracy. The phantom described in this paper was constructed to fit into a body coil of a MRI scanner, (external dimensions of the phantom were: 310 mm x 310 mm x 310 mm), and it contained 10,830 control points. With this phantom, the mean errors in the measured coordinates of the control points were on the order of 0.1 mm or less, which were less than one tenth of the voxel's dimensions of the phantom image. The calculated three-dimensional distortion map, i.e., the differences between the image positions and true positions of the control points, can then be used to compensate for geometric distortion for a full image restoration. It is anticipated that this novel method will have an impact on the applicability of MRI in both clinical and research settings. especially in areas where geometric accuracy is highly required, such as in MR neuro-imaging. (C) 2004 Elsevier Inc. All rights reserved.