Time-domain quantitation of 1H short echo-time signals:: background accommodation
Time-domain quantitation of 1H short echo-time signals:: background accommodation
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DOI：
10.1007/s10334-004-0037-9
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发表时间：
2004-05-01
影响因子：
2.3
通讯作者：
Graveron-Demilly, D
中科院分区：
文献类型：
--
作者：
Ratiney, H;Coenradie, Y;Graveron-Demilly, D
H-1短回波时间信号的定量常常受到主要来自大分子和脂质的背景信号的阻碍。虽然代谢物信号的模型函数是已知的，但大分子的模型函数仅部分已知。我们提出了时域半参数估计方法的基础上的QUEST定量算法（QUantation的基础上QUantum ESTimation），并涵盖克拉美-拉奥界处理的影响，“滋扰”的参数相关的背景。提出了三种新的背景调节方法。它们基于背景信号在时域中的快速衰减。在自动估计之后，背景信号可以自动地（1）从原始数据中减去，（2）作为多个分量包括在基集中，或（3）作为单个实体包括在基集中。这些方法结合QUEST的性能进行了评估，通过广泛的Monte Carlo研究。从偏差-方差权衡的角度对它们进行比较。由于振幅上的误差条对诊断可靠性至关重要，因此提出了考虑背景引起的不确定性的Cramer-Rao界。在体内短回波时间H-1人脑与估计的背景的定量与QUEST证明。
Quantitation of H-1 short echo-time signals is often hampered by a background signal originating mainly from macromolecules and lipids. While the model function of the metabolite signal is known, that of the macromolecules is only partially known. We present time-domain semi-parametric estimation approaches based on the QUEST quantitation algorithm (QUantitation based on QUantum ESTimation) and encompassing Cramer-Rao bounds that handle the influence of 'nuisance' parameters related to the background. Three novel methods for background accommodation are presented. They are based on the fast decay of the background signal in the time domain. After automatic estimation, the background signal can be automatically (1) subtracted from the raw data, (2) included in the basis set as multiple components, or (3) included in the basis set as a single entity. The performances of these methods combined with QUEST are evaluated through extensive Monte Carlo studies. They are compared in terms of bias-variance trade-off. Because error bars on the amplitudes are of paramount importance for diagnostic reliability, Cramer-Rao bounds accounting for the uncertainty caused by the background are proposed. Quantitation with QUEST of in vivo short echo-time H-1 human brain with estimation of the background is demonstrated.