Perturbation method for magnetic field calculations of nonconductive objects
Perturbation method for magnetic field calculations of nonconductive objects
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DOI：
10.1002/mrm.20194
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发表时间：
2004-09-01
影响因子：
3.3
通讯作者：
Jezzard, P
中科院分区：
文献类型：
--
作者：
Jenkinson, M;Wilson, JL;Jezzard, P
不均匀磁场在磁共振图像中产生伪影，包括信号丢失和空间失真。提出了一种新的计算非导电物体内部和周围一阶磁场（误差为二阶）的微扰方法。扰动参数是物体与其周围环境之间的敏感性差异（例如，在脑组织和空气的情况下，类似于10 ppm）。这种方法是有利的，因为它在大多数情况下都足够准确，可以通过与基于体素的对象模型的简单卷积来实现，并且是线性的。此外，该方法使用简单，可以使用一组预先计算的基图像快速计算出物体任意方向的场。(C) 2004 WileyLiss, Inc。
Inhomogeneous magnetic fields produce artifacts in MR images including signal dropout and spatial distortion. A novel perturbative method for calculating the magnetic field to first order (error is second order) within and around nonconducting objects is presented. The perturbation parameter is the susceptibility difference between the object and its surroundings (for example, similar to10 ppm in the case of brain tissue and air). This method is advantageous as it is sufficiently accurate for most purposes, can be implemented as a simple convolution with a voxel-based object model, and is linear. Furthermore, the method is simple to use and can quickly calculate the field for any orientation of an object using a set of precalculated basis images. (C) 2004 WileyLiss, Inc.