Dynamic correction of artifacts due to susceptibility effects and time-varying eddy currents in diffusion tensor imaging
Dynamic correction of artifacts due to susceptibility effects and time-varying eddy currents in diffusion tensor imaging
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DOI：
10.1016/j.neuroimage.2011.06.008
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发表时间：
2011-08-15
期刊：
影响因子：
5.7
通讯作者：
Song, Allen W.
中科院分区：
文献类型：
--
作者：
Trong-Kha Truong;Chen, Nan-kuei;Song, Allen W.
在弥散张量成像（DTI）中，由磁化率效应和时变涡流引起的静磁场（B（0））的空间和时间变化导致严重的失真、模糊和配准不良伪影，这又导致DTI度量和纤维束成像中的误差。已经提出了各种校正方法，但通常假设涡流感应磁场可以被建模为DTI读出窗口内的常数或单指数衰减。在这里，我们表明，它的时间依赖性是更复杂的，因为多个涡流与不同的时间常数的相互作用，但它仍然非常一致，随着时间的推移。因此，我们提出了一种新的动态B（0）映射和非共振校正方法，该方法测量磁化率和涡流感应磁场的精确空间、时间和扩散加权方向依赖性，以有效且高效地校正由磁化率效应和时变涡流引起的伪影，从而获得高空间保真度和准确度。(C)2011 Elsevier Inc. All rights reserved.
In diffusion tensor imaging (DTI), spatial and temporal variations of the static magnetic field (B(0)) caused by susceptibility effects and time-varying eddy currents result in severe distortions, blurring, and misregistration artifacts, which in turn lead to errors in DTI metrics and in fiber tractography. Various correction methods have been proposed, but typically assume that the eddy current-induced magnetic field can be modeled as a constant or a single exponential decay within the DTI readout window. Here, we show that its temporal dependence is more complex because of the interaction of multiple eddy currents with different time constants, but that it remains very consistent over time. As such, we propose a novel dynamic B(0) mapping and off-resonance correction method that measures the exact spatial, temporal, and diffusion-weighting direction dependence of the susceptibility- and eddy current-induced magnetic fields to effectively and efficiently correct for artifacts caused by both susceptibility effects and time-varying eddy currents, thereby resulting in a high spatial fidelity and accuracy. (C) 2011 Elsevier Inc. All rights reserved.