磁共振成像引导下异质腔室的空间定位
Image-guided spatial localization of heterogeneous compartments for magnetic resonance.
作者信息
An Li, Shen Jun
机构信息
Section on Magnetic Resonance Spectroscopy, Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Bethesda, Maryland 20854.
出版信息
Med Phys. 2015 Sep;42(9):5278-86. doi: 10.1118/1.4928398.
PURPOSE
Image-guided localization SPectral Localization Achieved by Sensitivity Heterogeneity (SPLASH) allows rapid measurement of signals from irregularly shaped anatomical compartments without using phase encoding gradients. Here, the authors propose a novel method to address the issue of heterogeneous signal distribution within the localized compartments.
METHODS
Each compartment was subdivided into multiple subcompartments and their spectra were solved by Tikhonov regularization to enforce smoothness within each compartment. The spectrum of a given compartment was generated by combining the spectra of the components of that compartment. The proposed method was first tested using Monte Carlo simulations and then applied to reconstructing in vivo spectra from irregularly shaped ischemic stroke and normal tissue compartments.
RESULTS
Monte Carlo simulations demonstrate that the proposed regularized SPLASH method significantly reduces localization and metabolite quantification errors. In vivo results show that the intracompartment regularization results in ∼ 40% reduction of error in metabolite quantification.
CONCLUSIONS
The proposed method significantly reduces localization errors and metabolite quantification errors caused by intracompartment heterogeneous signal distribution.
目的
基于敏感性异质性实现的图像引导定位光谱定位法（SPLASH）可在不使用相位编码梯度的情况下快速测量来自不规则形状解剖区域的信号。在此，作者提出一种新方法来解决局部区域内信号分布不均的问题。
方法
将每个区域细分为多个子区域，并通过蒂霍诺夫正则化求解其光谱，以确保每个区域内的平滑度。给定区域的光谱通过组合该区域各成分的光谱生成。所提出的方法首先使用蒙特卡罗模拟进行测试，然后应用于从不规则形状的缺血性中风和正常组织区域重建体内光谱。
结果
蒙特卡罗模拟表明，所提出的正则化SPLASH方法显著降低了定位和代谢物定量误差。体内结果表明，区域内正则化使代谢物定量误差降低了约40%。
结论
所提出的方法显著降低了由区域内异质信号分布引起的定位误差和代谢物定量误差。
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