MRS Shimming: An Important Point Which Should not be Ignored
MRS Shimming: An Important Point Which Should not be Ignored
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MRS Shimming：不容忽视的重要一点
DOI：
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发表时间：
2018
影响因子：
--
通讯作者：
L. Mina
中科院分区：
文献类型：
--
作者：
B. Zeinali;R. Faghihi;M. Mosleh;M. Saeedi;M. Lotfi;R. Jalli;S. Sina;L. Mina
背景：质子磁共振波谱（MRS）是一种常用的生物体液代谢分析设备。通过MRS获得准确可靠的信息需要均匀的磁场，以便提供明确的峰值和均匀的水抑制。有很多原因会干扰磁场均匀性，可以通过称为匀场的过程进行校正。本研究旨在回顾匀场的重要性以及质量控制（QC）在实现准确定量方面的重要作用。材料和方法：为了控制Shiraz医院的1.5T Siemens MRI系统获得的信号的准确性，设计了一个丙烯酸圆柱形质量控制体模作为脑部MRS测试体模的模拟物。使用单独的模型评价NAA、Cho、Cr、这些代谢物的组合以及本研究中使用的蒸馏水的信号。使用Siemens QC体模和标准测试体模进行QC测试。结果：自制体模的光谱与预期光谱有显著差异.分别检查代谢物光谱的结果也证实，存在影响所有代谢物甚至纯蒸馏水产生的所有信号的系统性问题。MRS系统不能通过QC测试，并且在所有光谱中峰增宽是常见的。MRS系统未能成功产生标准测试体模的复杂光谱。讨论内容：通过对水峰特性的简单检查，可以获得许多信息，其中之一是对光谱准确性有相当大影响的匀场状态。因此，执行自动或手动匀场不是光谱精度的标准，并且需要由专家使用测试体模执行周期性质量控制。结论：应重视磁共振波谱仪及其他临床设备的质量控制。有时QC可能是患者正确或错误决定的边界。
Background: Proton magnetic resonance spectroscopy (MRS) is a well-known device for analyzing the biological fluids metabolically. Obtaining accurate and reliable information via MRS needs a homogeneous magnetic field in order to provide well-defined peaks and uniform water suppression. There are lots of reasons which can disturb the magnetic field homogeneity which can be corrected by a process known as shimming. This study is intended to recall the importance of shimming and also the significant role of quality control (QC) in achieving an accurate quantification. Material and Method: An acrylic cylindrical quality control phantom was designed as an analog of brain MRS test phantoms in order to control the accuracy of the obtained signal of a 1.5 T Siemens MRI system which belonged to one of Shiraz hospitals. The signal of NAA, Cho, Cr, the combination of these metabolites and also the distilled water, which was used in this study, was evaluated using separate phantoms. A QC test was performed using Siemens QC phantom and a standard test phantom. Results: The spectrum of our home- made phantom had a significant difference with the expected spectrum. The results of checking the spectrum of metabolites separately also confirmed that there was a systemic problem that affects all the signals originated from all metabolites and even the pure distilled water. The MRS system could not pass QC tests, and peak broadening was common in all spectra. The complex spectrum of standard test phantom was not produced successfully by the MRS system. Discussion: By a simple check of the water peak characteristics, lots of information can be obtained, one of which is the status of shimming that has a considerable effect on the accuracy of the spectrum. Thus, performing an automatic or manual shimming is not a criterion of the spectrum accuracy, and performing a periodic quality control using a test phantom by a specialist is necessary. Conclusion: Briefly, the quality control of MRS and all the other clinical device must be taken seriously. Sometimes QC can be the boundary of a right or a wrong decision for the patient.
影响因子：
2.9
作者：
Juchem C;de Graaf RA
通讯作者：
de Graaf RA