Quantitative susceptibility mapping for investigating subtle susceptibility variations in the human brain
Quantitative susceptibility mapping for investigating subtle susceptibility variations in the human brain
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DOI：
10.1016/j.neuroimage.2012.05.067
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发表时间：
2012-09-01
期刊：
影响因子：
5.7
通讯作者：
Reichenbach, Juergen Rainer
中科院分区：
文献类型：
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作者：
Schweser, Ferdinand;Sommer, Karsten;Reichenbach, Juergen Rainer
定量磁化率测绘 (QSM) 是一种基于磁共振的新型技术，可通过磁场扰动的测量来确定组织磁化率。由于该问题的不适定性质，通常需要正则化策略来减少计算地图上的条纹伪影。本研究引入了一种新的算法，利用从梯度回波相位图像导出的区域均匀性的先验信息来计算磁化率分布，并分析了错误的先验信息对磁化率图保真度的影响。该算法名为均质性增量偶极子反演 (HEIDI)，特别关注数值模型和志愿者数据中细微磁化率变化的重建，并与最近发布的两种方法（阈值 K 空间除法 (TKD) 和形态学启用偶极子反演 (MEDI)）进行了比较。 HEIDI 生成的磁化率图没有条纹伪影，并且出色地描述了大多数区域的细微磁化率变化。通过研究志愿者头部不同方向获取的HEIDI磁化率图，证明人脑组织的表观磁化率分布在很大程度上取决于主磁场的方向。 (C) 2012 Elsevier Inc. 保留所有权利。
Quantitative susceptibility mapping (QSM) is a novel magnetic resonance-based technique that determines tissue magnetic susceptibility from measurements of the magnetic field perturbation. Due to the ill-posed nature of this problem, regularization strategies are generally required to reduce streaking artifacts on the computed maps. The present study introduces a new algorithm for calculating the susceptibility distribution utilizing a priori information on its regional homogeneity derived from gradient echo phase images and analyzes the impact of erroneous a priori information on susceptibility map fidelity. The algorithm, Homogeneity Enabled Incremental Dipole Inversion (HEIDI), was investigated with a special focus on the reconstruction of subtle susceptibility variations in a numerical model and in volunteer data and was compared with two recently published approaches, Thresholded K-space Division (TKD) and Morphology Enabled Dipole Inversion (MEDI). HEIDI resulted in susceptibility maps without streaking artifacts and excellent depiction of subtle susceptibility variations in most regions. By investigating HEIDI susceptibility maps acquired with the volunteers' heads in different orientations, it was demonstrated that the apparent magnetic susceptibility distribution of human brain tissue considerably depends on the direction of the main magnetic field. (C) 2012 Elsevier Inc. All rights reserved.