超低场磁共振膝关节正交接收线圈设计

doi:10.19595/j.cnki.1000-6753.tces.230089

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摘要

射频接收线圈是磁共振成像（MRI）系统中的关键部件,用于检测变化的磁场,其性能直接影响了图像的质量。超低场MRI射频接收线圈工作在较低频率,其阻抗特性不同于传统临床MRI射频接收线圈。理论上正交接收线圈比单通道线圈的信噪比（SNR）可以提高41%。而与阵列线圈相比,正交接收线圈可以用更低的成本与设计复杂度达到很好的成像效果。因此该文研究了一种用于超低场MRI（50.4 mT）系统的膝关节正交接收线圈,它由鞍形线圈和亥姆霍兹线圈组成。首先,本文确定了线圈的支撑结构及尺寸,并通过计算单匝接收线圈的效率以及磁场的不均匀性来确定鞍形以及亥姆霍兹线圈的最优尺寸。然后,该文实测了线圈交流电阻,来评估线圈不同匝数的SNR,发现匝数增多会使得交流电阻显著增加,从而使SNR随着线圈匝数增加先增加后减少。最后,本文得到了两线圈的最佳匝数,并制作了正交接收线圈。从CuSO₄·5H₂O体膜以及体内膝关节成像来评估正交接收线圈的性能。在体膜和体内膝关节成像中,正交接收线圈与单通道线圈相比,图像SNR最大程度上分别提升了约33.5%和 30.9%。

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关键词 ：磁共振成像, 超低场, 膝关节成像, 正交接收线圈

Abstract：

The radio frequency (RF) receive coil is a key component in a magnetic resonance imaging (MRI) system, and its performance directly affects the quality of the MR images. Currently, the RF coil performance is mostly measured by RF magnetic field inhomogeneity and signal-to-noise ratio (SNR). In SNR calculations, the main contribution to noise is made by the coil resistance, including conductor losses and sample losses caused by RF currents. At low frequencies, the latter can be neglected. The ultra-low-field (ULF) MRI RF receive coil has a low working frequency and, therefore, has different impedance characteristics than the conventional clinical MRI RF receive coil, leading to different optimal RF coil configurations. This paper optimized a knee RF receive coil for an ultra-low field MRI system and investigated the relationship between RF coil construction and performance.
Specifically, this paper investigated a knee quadrature receive coil. Theoretically, a quadrature receive coil can improve the SNR by 41% over a single-channel coil. Compared to an array coil, a quadrature receive coil can achieve good imaging results at a lower cost and with less design complexity. The quadrature receive coil in this paper consists of a saddle coil and a Helmholtz coil. Firstly, the support structure and dimensions of the coil were determined, and the optimum size of the saddle and Helmholtz coils was determined by calculating the efficiency of the single-turn receive coil and the RF magnetic field inhomogeneity. Then, the paper further investigated the performance of the optimally sized RF coil in terms of the number of turns. Using the measured coil AC resistance, it is found that the number of turns is a significant feature affecting the AC resistance of the RF coil for ultra-low field MRI, and it is found that an increase in the number of turns leads to a significant increase in the AC resistance, resulting in an increase and then a decrease in SNR as the number of turns increases.
Finally, the optimal number of turns for both coils was obtained, and a quadrature receive coil was fabricated. The performance of the quadrature receive coil was evaluated using CuSO₄·5H₂O phantom and in vivo knee imaging. In phantom imaging, the quadrature receive coil shows a maximum image SNR improvement of approximately 33.5% compared to the single channel coil. In in vivo knee imaging, T₁- and T₂-weighted images were obtained using GRE3D and FSE sequences, respectively, from which the structural composition of the knee can be clearly observed. The quadrature receive coil shows maximum image SNR improvements of approximately 30.9% and 27.9%, respectively, over the single-channel coil. The results show that knee imaging in an ultra-low-field MRI system is feasible and that the quadrature receive coil performance is superior to that of a single-channel receive coil. This paper analyses and optimizes the coil from the perspective of the number of turns of the RF receive coil, revealing that the number of turns of the coil is an important factor affecting the SNR of the ULF-MRI RF receive coil, providing new evidence for the design and optimization of RF coils.

Key words： Magnetic resonance imaging ultra-low field knee imaging quadrature receive coil

收稿日期: 2023-01-18

PACS:	TM153+.1
	R445.2

基金资助:

国家自然科学基金（52077023）、重庆市自然科学基金（cstc2020jcyj-msxmX0340）、重庆市教委自然科学项目（KJQN202100533）和深圳市科技创新委员会（CJGJZD20200617102402006）资助项目

通讯作者: 徐征, 男,1980年生,教授,博士生导师,研究方向为生物电磁成像技术。E-mail：xuzheng@cqu.edu.cn

作者简介: 万裁 , 男,1996年生,博士研究生,研究方向生物电磁技术。E-mail：20181113069t@cqu.edu.cn

引用本文:

万裁, 何为, 沈晟, 徐征. 超低场磁共振膝关节正交接收线圈设计[J]. 电工技术学报, 0, (): 9014-14. Wan Cai, He Wei, Shen Sheng, Xu Zheng. Design of a Quadrature Receive Coil for Ultra-low-field Knee Magnetic Resonance Imaging. Transactions of China Electrotechnical Society, 0, (): 9014-14.

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[1] 李晓南, 任雯廷, 刘国强, 等. 高分辨率磁共振电特性成像及脑肿瘤诊断初步研究[J]. 电工技术学报, 2021, 36(18): 3860-3866.
Li Xiaonan, Ren Wenting, Liu Guoqiang, et al.Preliminary conductivity reconstruction by high-resolution magnetic resonance electrical properties tomography for brain tumor diagnosis[J]. Transactions of China Electrotechnical Society, 2021, 36(18): 3860-3866.
[2] 陈顺中, 王秋良, 孙万硕, 等. 3T动物磁共振成像传导冷却超导磁体研究[J]. 电工技术学报, 2023, 38(4): 879-888.
Chen Shunzhong, Wang Qiuliang, Sun Wanshuo, et al.The study of a 3T conduction-cooled superconducting magnet for animal magnetic resonance imaging[J]. Transactions of China Electrotechnical Society, 2023, 38(4): 879-888.
[3] 冯焕, 姜晖, 王雪梅. 功能磁共振成像在肿瘤学领域的应用[J]. 电工技术学报, 2021, 36(4): 705-716.
Feng Huan, Jiang Hui, Wang Xuemei.Application of functional magnetic resonance imaging in the field of oncology[J]. Transactions of China Electrotechnical Society, 2021, 36(4): 705-716.
[4] Yang Lei, He Wei, He Yucheng, et al.Active EMI suppression system for a 50 mT unshielded portable MRI scanner[J]. IEEE Transactions on Bio-Medical Engineering, 2022, 69(11): 3415-3426.
[5] Ma D, Gulani V, Seiberlich N, et al.Magnetic resonance fingerprinting[J]. Nature, 2013, 495(7440): 187-192.
[6] Sarracanie M, LaPierre CD, Salameh N, et al. Low-cost high-performance MRI[J]. Scientific Reports, 2015, 5(1): 15177.
[7] He Yucheng, He Wei, Tan Liang, et al.Use of 2.1 MHz MRI scanner for brain imaging and its preliminary results in stroke[J]. Journal of Magnetic Resonance, 2020, 319: 106829.
[8] O'Reilly T, Teeuwisse W M, de Gans D, et al. In vivo 3D brain and extremity MRI at 50 mT using a permanent magnet Halbach array[J]. Magnetic Resonance in Medicine, 2021, 85(1): 495-505.
[9] Sheth K N, Mazurek M H, Yuen M M, et al.Assessment of brain injury using portable, low-field magnetic resonance imaging at the bedside of critically ill patients[J]. JAMA Neurology, 2021, 78(1): 41-47.
[10] Mazurek M H, Cahn B A, Yuen M M, et al.Portable, bedside, low-field magnetic resonance imaging for evaluation of intracerebral hemorrhage[J]. Nature Communications, 2021, 12(1): 5119.
[11] Liu Y, Leong A T, Zhao Y, et al.A low-cost and shielding-free ultra-low-field brain MRI scanner[J]. Nature Communications, 2021, 12(1): 7238.
[12] 贺中华, 何为, 贺玉成, 等. 皮肤烧伤深度检测的单边核磁共振浅层成像磁体系统[J]. 电工技术学报, 2019, 34(3): 449-458.
He Zhonghua, He Wei, He Yucheng, et al.Unilateral nuclear magnetic resonance superficial imaging magnet system for skin burn depth assessment[J]. Transactions of China Electrotechnical Society, 2019, 34(3): 449-458.
[13] Gruber B, Froeling M, Leiner T, et al.RF coils: A practical guide for nonphysicists[J]. Journal of magnetic resonance imaging, 2018, 48(3): 590-604.
[14] Lee H S, Woo D C, Min K H, et al.Development of a solenoid RF coil for animal imaging in 3 T high‐magnetic‐field MRI[J]. Scanning, 2008, 30(5): 419-425.
[15] Giovannetti G, Frijia F, Flori A, et al.Design and simulation of a Helmholtz coil for Magnetic Resonance Imaging and Spectroscopy experiments with a 3T MR clinical scanner[J]. Applied Magnetic Resonance, 2019, 50(9): 1083-1097.
[16] Shen Sheng, Xu Zheng, Neha Koonjoo, et al.Optimization of a close-fitting volume RF coil for brain imaging at 6.5 mT using linear programming[J]. IEEE Transactions on Biomedical Engineering, 2020, 68(4): 1106-1114.
[17] Blasiak B, Volotovskyy V, Tyson R, et al.An RF breast coil for 0.2 T MRI[J]. Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering, 2016, 46(1): 3-7.
[18] Sank V, Chen C-N, Hoult D.A quadrature coil for the adult human head[J]. Journal of Magnetic Resonance, 1986, 69(2): 236-242.
[19] Kumar A, Bottomley PA.Optimized quadrature surface coil designs[J]. Magnetic Resonance Materials in Physics, Biology and Medicine, 2008, 21(1-2): 41-52.
[20] Zailaa A, Vegh V, Maillet D, et al.Quadrature radio frequency coil for magnetic resonance imaging of the wrist at 4T[J]. Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering, 2009, 35(4): 191-197.
[21] Tomanek B, Volotovskyy V, Tyson R, et al.A quadrature volume RF coil for vertical B0 field open MRI systems[J]. Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering, 2016, 46(3): 118-122.
[22] Fujita H, Braum W O, Morich M A.Novel quadrature birdcage coil for a vertical B0 field open MRI system[J]. Magnetic Resonance in Medicine, 2000, 44(4): 633-640
[23] Giovannetti G, Francesconi R, Landini L, et al.A quadrature lowpass birdcage coil for a vertical low field MRI scanner[J]. Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering, 2004, 22(1): 1-6.
[24] Roemer P B, Edelstein W A, Hayes C E, et al.The NMR phased array[J]. Magnetic resonance in medicine, 1990, 16(2): 192-225.
[25] Schmitt M, Potthast A, Sosnovik DE, et al.A 128‐channel receive‐only cardiac coil for highly accelerated cardiac MRI at 3 Tesla[J]. Magnetic Resonance in Medicine, 2008, 59(6): 1431-1439.
[26] Chen Qiaoyan, Xu Yajie, Chang Yan, et al.Design and Demonstration of Four-Channel Received Coil Arrays for Vertical-Field MRI[J]. Applied Magnetic Resonance, 2017, 48(5): 501-515.
[27] Chen C N, Hoult D, Sank VJ.Quadrature detection coils—A further √2 improvement in sensitivity[J]. Journal of Magnetic Resonance, 1983, 54(2): 324-327.
[28] Giovannetti G, Frijia F, Hartwig V, et al.Design of a quadrature surface coil for hyperpolarized 13C MRS cardiac metabolism studies in pigs[J]. Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering, 2013, 43(2): 69-77.
[29] Glover G, Hayes C, Pelc N, et al.Comparison of linear and circular polarization for magnetic resonance imaging[J]. Journal of Magnetic Resonance, 1985, 64(2): 255-270.
[30] Park J, Zhang Qiang, Jellus V, O. et al. Artifact and noise suppression in GRAPPA imaging using improved k-space coil calibration and variable density sampling[J]. Magnetic Resonance in Medicine, 2005, 53(1): 186-193.
[31] Pruessmann K P, Weiger M, Scheidegger M B, et al.SENSE: sensitivity encoding for fast MRI[J]. Magnetic Resonance in Medicine, 1999, 42(5): 952-962.
[32] Lawrence B G, Crozier S, Yau D D, et al.A time-harmonic inverse methodology for the design of RF coils in MRI[J]. IEEE transactions on biomedical engineering, 2002, 49(1): 64-71.
[33] Fujita H, Petropoulos LS, Morich MA, et al.A hybrid inverse approach applied to the design of lumped-element RF coils[J]. IEEE transactions on biomedical engineering, 1999, 46(3): 353-361.
[34] Wright SM, Wald LL.Theory and application of array coils in MR spectroscopy[J]. NMR in Biomedicine, 1997, 10(8): 394-410.
[35] Wu Bing, Qu Peng, Wang Chunsheng, et al.InterconnectingL/C components for decoupling and its application to low-field open MRI array[J]. Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering, 2007, 31(2): 116-126.
[36] 徐显能,徐征. 印制电路板射频线圈的部分元等效电路研究[J]. 电工技术学报, 2022, 37(17): 4284-4293.
Xu Xianneng, Xu Zheng.Research on the partial element equivalent circuit of radio frequency coil on the printed circuit board[J]. Transactions of China Electrotechnical Society, 2022, 37(17): 4284-4293.