In vivo 31P MRS of human brain at high/ultrahigh fields:: a quantitative comparison of NMR detection sensitivity and spectral resolution between 4 T and 7 T
In vivo 31P MRS of human brain at high/ultrahigh fields:: a quantitative comparison of NMR detection sensitivity and spectral resolution between 4 T and 7 T
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DOI：
10.1016/j.mri.2006.08.002
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发表时间：
2006-12-01
影响因子：
2.5
通讯作者：
Chen, Wei
中科院分区：
文献类型：
--
作者：
Qiao, Hongyan;Zhang, Xiaoliang;Chen, Wei
这项研究的主要目标是建立一种严格的方法来确定和比较体内P-31MRS在不同场强(B-0)下的核磁共振检测灵敏度。这是通过计算在给定场强下在单位采样时间内实现的信噪比(SNR)来实现的。在相同的实验条件下，分别在4T和7T下获得了活体人枕叶的P-31波谱。它们被用来测量当场强从4T增加到7T时人脑P-31MRS的改善情况，并在这两个场强下测量了磷酸肌酸(PCR)共振峰的驰豫时间和线宽以及射频线圈的品质因数(Q)。分析和讨论了它们在一定场强下对信噪比的相对贡献。结果表明，与4T相比，7T时P-31在体内的灵敏度显著提高，并且随着B-0的增加，其共振峰的线宽不是线性增加，从而导致P-31光谱分辨率的显著提高。这些发现表明，高场强在改善体内P-31MRS质量方面具有优势，在灵敏度和光谱分辨率方面都是如此。这一优势将提高体内P-31MRS在非侵入性研究人类正常和疾病状态下的高能磷酸盐代谢、磷脂代谢和脑生物遗传学方面的可靠性和适用性。最后，本研究中用于计算体内P-31MRS灵敏度的方法提供了一个通用工具，用于估计在给定场强下任何核自旋的相对核磁共振检测灵敏度。(C)2006 Elsevier Inc.保留所有权利。
The primary goal of this study was to establish a rigorous approach for determining and comparing the NMR detection sensitivity of in vivo P-31 MRS at different field strengths (B-0). This was done by calculating the signal-to-noise ratio (SNR) achieved within a unit sampling time at a given field strength. In vivo P-31 spectra of human occipital lobe were acquired at 4 and 7 T under similar experimental conditions. They were used to measure the improvement of the human brain P-31 MRS when the field strength increases from 4 to 7 T. The relaxation times and line widths of the phosphocreatine (PCr) resonance peak and the RF coil quality factors (Q) were also measured at these two field strengths. Their relative contributions to SNR at a given field strength were analyzed and discussed. The results show that in vivo P-31 sensitivity was significantly improved at 7 T as compared with 4 T. Moreover, the line-width of the PCr resonance peak showed less than a linear increase with increased B-0, which leads to a significant improvement in P-31 spectral resolution. These findings indicate the advantage of high-field strength to improve in vivo P-31 MRS quality in both sensitivity and spectral resolution. This advantage should improve the reliability and applicability of in vivo P-31 MRS in studying high-energy phosphate metabolism, phospholipid metabolism and cerebral biogenetics in the human at both normal and diseased states noninvasively. Finally, the approach used in this study for calculating in vivo P-31 MRS sensitivity provides a general tool in estimating the relative NMR detection sensitivity for any nuclear spin at a given field strength. (c) 2006 Elsevier Inc. All rights reserved.