文档名：超低场磁共振膝关节正交接收线圈设计
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(50.4mT)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,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,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,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分别最大程度地提升了约33.5%和30.9%.
Abstract：Theradiofrequency(RF)receivecoilisakeycomponentinamagneticresonanceimaging(MRI)system,anditsperformancedirectlyaffectsthequalityoftheMRimages.Currently,theRFcoilperformanceismostlymeasuredbyRFmagneticfieldinhomogeneityandsignal-to-noiseratio(SNR).InSNRcalculations,themaincontributiontonoiseismadebythecoilresistance,includingconductorlossesandsamplelossescausedbyRFcurrents.Atlowfrequencies,thelattercanbeneglected.Theultra-low-field(ULF)MRIRFreceivecoilhasalowworkingfrequencyand,therefore,hasdifferentimpedancecharacteristicsthantheconventionalclinicalMRIRFreceivecoil,leadingtodifferentoptimalRFcoilconfigurations.ThispaperoptimizedakneeRFreceivecoilforanultra-lowfieldMRIsystemandinvestigatedtherelationshipbetweenRFcoilconstructionandperformance.Specifically,thispaperinvestigatedakneequadraturereceivecoil.Theoretically,aquadraturereceivecoilcanimprovetheSNRby41%overasingle-channelcoil.Comparedtoanarraycoil,aquadraturereceivecoilcanachievegoodimagingresultsatalowercostandwithlessdesigncomplexity.ThequadraturereceivecoilinthispaperconsistsofasaddlecoilandaHelmholtzcoil.Firstly,thesupportstructureanddimensionsofthecoilweredetermined,andtheoptimumsizeofthesaddleandHelmholtzcoilswasdeterminedbycalculatingtheefficiencyofthesingle-turnreceivecoilandtheRFmagneticfieldinhomogeneity.Then,thepaperfurtherinvestigatedtheperformanceoftheoptimallysizedRFcoilintermsofthenumberofturns.UsingthemeasuredcoilACresistance,itisfoundthatthenumberofturnsisasignificantfeatureaffectingtheACresistanceoftheRFcoilforultra-lowfieldMRI,anditisfoundthatanincreaseinthenumberofturnsleadstoasignificantincreaseintheACresistance,resultinginanincreaseandthenadecreaseinSNRasthenumberofturnsincreases.Finally,theoptimalnumberofturnsforbothcoilswasobtained,andaquadraturereceivecoilwasfabricated.TheperformanceofthequadraturereceivecoilwasevaluatedusingCuSO4·5H2Ophantomandinvivokneeimaging.Inphantomimaging,thequadraturereceivecoilshowsamaximumimageSNRimprovementofapproximately33.5%comparedtothesinglechannelcoil.Ininvivokneeimaging,T1-andT2-weightedimageswereobtainedusingGRE3DandFSEsequences,respectively,fromwhichthestructuralcompositionofthekneecanbeclearlyobserved.ThequadraturereceivecoilshowsmaximumimageSNRimprovementsofapproximately30.9%and27.9%,respectively,overthesingle-channelcoil.Theresultsshowthatkneeimaginginanultra-low-fieldMRIsystemisfeasibleandthatthequadraturereceivecoilperformanceissuperiortothatofasingle-channelreceivecoil.ThispaperanalysesandoptimizesthecoilfromtheperspectiveofthenumberofturnsoftheRFreceivecoil,revealingthatthenumberofturnsofthecoilisanimportantfactoraffectingtheSNRoftheULF-MRIRFreceivecoil,providingnewevidenceforthedesignandoptimizationofRFcoils.
作者：万裁 何为 沈晟 徐征 Author：WanCai HeWei ShenSheng XuZheng
作者单位：重庆大学电气工程学院重庆400044重庆大学电气工程学院重庆400044;麻省总医院AthinoulaA.Martinos生物医学成像中心美国马萨诸塞州02114
刊名：电工技术学报
Journal：TransactionsofChinaElectrotechnicalSociety
年，卷(期)：2024, 39(7)
分类号：TM153+.1R445.2
关键词：磁共振成像 超低场 膝关节成像 正交接收线圈
Keywords：Magneticresonanceimaging ultra-lowfield kneeimaging quadraturereceivecoil
机标分类号：R445.2R743.33O413
在线出版日期：2024年4月12日
基金项目：国家自然科学基金，重庆市自然科学基金，重庆市教委自然科学项目，深圳市科技创新委员会资助项目超低场磁共振膝关节正交接收线圈设计[
期刊论文] 电工技术学报--2024, 39(7)万裁 何为 沈晟 徐征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...参考文献和引证文献
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超低场磁共振膝关节正交接收线圈设计 Design of a Quadrature Receive Coil for Ultra-Low-Field Knee Magnetic Resonance Imaging
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