integrated ssfp for functional brain mapping at 7 t with reduced susceptibility artifact kaibao sun资料.pdf

该【integrated ssfp for functional brain mapping at 7 t with reduced susceptibility artifact kaibao sun资料 】是由【十二官】上传分享，文档一共【30】页，该文档可以免费在线阅读，需要了解更多关于【integrated ssfp for functional brain mapping at 7 t with reduced susceptibility artifact kaibao sun资料 】的内容，可以使用淘豆网的站内搜索功能，选择自己适合的文档，以下文字是截取该文章内的部分文字，如需要获得完整电子版，请下载此文档到您的设备，方便您编辑和打印。:..AcceptedManuscriptIntegratedSSFPforfunctionalbrainmappingat7TwithreducedsusceptibilityartifactKaibaoSun,RongXue,PengZhang,ZhentaoZuo,ZhongweiChen,BoWang,ThomasMartin,YiWang,LinChen,ShengHe,:S1090-7807(16)30276-2DOI:http://dx./.:YJMRE6011Toappearin:icResonanceReceivedDate:21June2016RevisedDate:21December2016AcceptedDate:22December2016Pleasecitethisarticleas:,,,,,,,,,,,IntegratedSSFPforfunctionalbrainmappingat7Twithreducedsusceptibilityartifact,JournalicResonance(2016),doi:http://dx./.,typesetting,,andalllegaldisclaimersthatapplytothejournalpertain.:..IntegratedSSFPforfunctionalbrainmappingat7Twithreducedsusceptibilityartifacta,ba,b,c*a,ba,ba,baKaibaoSun,RongXue,PengZhang,ZhentaoZuo,ZhongweiChen,BoWang,eea,b,g*a,b,de,fThomasMartin,YiWang,LinChen,ShengHeandDannyJJWangaStateKeyLaboratoryofBrainandCognitiveScience,BeijingMRICenterforBrainRe-search,InstituteofBiophysics,ChineseAcademyofSciences,Beijing,100101,ChinabUniversityofChineseAcademyofSciences,Beijing100049,ChinacBeijingInstituteforBrainDisorders,Beijing100053,ChinadDepartmentofPsychology,UniversityofMinnesota,Minneapolis,Minnesota,55455,UnitedStateseDepartmentofNeurology,UniversityofCaliforniaLosAngeles,LosAngeles,90095,UnitedStatesfStevensNeuroimagingandInformaticsInstitute,UniversityofSouthernCalifornia,LosAngeles,California,UnitedStatesgTheInnovationCenterofExcellenceonBrainScience,ChineseAcademyofSciences*Correspondenceto:RongXueorLinChen,,BeijingMRICenterforBrainResearch,InstituteofBiophysics,ChineseAcademyofSci-ences,15DatunRoad,ChaoyangDistrict,Beijing100101,:******@.******@:..AbstractBalancedsteady-statefreeprecession(bSSFP)offersanalternativeandpotentiallyim-portanttooltothestandardgradient-echoecho-planarimaging(GE-EPI)forfunctionalMRI(fMRI).,however,arelimitedbybandingartifactsduetothesensitivityofbSSFPsignaltooff-,auniquecaseoftheSSFP-FIDse-quence,termedintegrated-SSFPoriSSFP,-°and25°,com-paredtostandardbSSFPandgradientecho(GRE)imaging.-±(%)±(%)forflipangles(FA)of4°and25°-sliceacquisition(SMS)withtheCAIPIRIHNAtechniquewascarriedoutwithiSSFPscanningtodetecttheparedwithstandard2DGE-,:IntegratedSSFP(iSSFP);fMRI;icfield;susceptibilityartifact;semantic2:..(BOLDfMRI)hasrevolutionizedthefieldoffunctionalbrainimagingsinceitsinception[1–3].MostexistingfMRIstudiesusedgradient-echoecho-planarimaging(GE-EPI),duetoitswhole-brainspatialcoverage,fastimagingspeedandrelativelyhighcontrast-to-R).Althoughwidelyused,BOLDfMRIsuffersfromsignaldropouts[4]andimagedistortions[5,6]thatimpairimaginginspecificbrainregions,suchastheanteriortemporallobeandor-bitofrontalcortexattheinterfaceofair,-icfields,,balancedsteady-statefreeprecession(bSSFP)hasbeenproposed,asanalternativeofGE-EPI,forfMRItoover--inducedfrequencyshifts[7,8],whilemorerecentstudiesshiftedfocustowardstherelativelyflatpassbandfordetectingmicro-scopicdiffusionrelatedsignalchanges[9–11].However,itremainsdifficulttoachievethewhole-braincoverageusingbSSFPduetothebandingartifactsarisingfromthesensitivityofbSSFPsignaltooff--binedtoachievefullcoverage,thescanningtimewillbemulti-pliedbythenumberofphasecycling[12].InadditiontobSSFP,afewalternativeSSFPse-quenceswithunbalancedgradientstoattainSSFP-FIDandSSFP-echosignals,havebeenex-ploredforfMRI[13–15].TheappealoftheseSSFPmethodsisthewhole-,-FIDwithstrongdephasinggradients,thefunctionalcontrastissensitive3:..todiffusionofspinsinthefielddisturbancessurroundingdeoxygenatedbloodvessels(largedrainingveins)[13].FortheSSFP-echosignal,thefunctionalcontrastissusceptibletotheeffectsofflowduetothestrongdephasinggradientandtheextravascularcontributionfromdynamicaveragingaroundpost-capillaryvesselsbecauseofitslongdiffusiontime[15].Inthisstudy,aspecialcaseofSSFP-FIDsequences,termedintegrated-SSFPoriSSFPwasproposedforfMRIat7Ttoachieverobustsignalchangeswithnegligiblesusceptibilityarti-facts[16,17].TheiSSFPsequencewasmodifiedfrombSSFPbyplacingagradientalongtheZaxisorXaxistodephasethespinsacrossa2πcyclewithinonevoxel(hereinreferredasiSSFPzandiSSFPx,respectively).Asaresult,themagnitudeoftheiSSFPsignalwaskeptconstantwhileitsphasevariedlinearlywiththefrequency,irrespectiveofthecenterfre-[18–20].TheiSSFPfMRIexperimentswithvisualstimulationwereperformedattwoflipanglesof4°and25°,,spatialspecificity,-tion,[21,22].However,obeaffectedbysusceptibilityartifacts[23].Subsequently,acomparativestudybetweensimultaneousmulti-sliceacquisition(SMS)acceleratediSSFP[24]andtraditionalstandard2DGE-,and4:..paredtostandard2DGE--,thetotalgradientareaonanyaxisiszeroduringeachTR(TR<<T2<T1),izationofbSSFPisgivenby[25,26]:MMEED?()(1)sin(1cos)/????????(1)y012MMEED?()(1)sinsin/????????(2)x012withDEEEEE??????????(1cos)(1cos)(cos)(cos)????(3)12212where,?istheflipangleoftheradiofrequency(RF)pulseand?isETRT1,21,2??exp/????acquiredTfromonevoxelatTE(0??TETR)plexintegral:(4)??MTETETpMiMiTETRdTxy()exp(/)()(()())exp(/)???2?V?????wherep()?isthedephasingdistributionwithintheimagingvolumeV,reflectingthecor-,(5)????LGdt?02whereGistheextradephasinggradient,and?,p()?in5:..,parisonwiththebSSFPsignalforflipanglesofboth4°and25°.Inthesimulation,theT1(2000ms)andT2(60ms)[14]valuesofgraymatterat7Twereused,(solidline).Aspoilinggradient(dottedline)isplacedrightbeforethesliceselectivegradient(a)orafterthereadoutgradient(b)-,iSSFPsignalhasconstantmagnitudeandlinearphaseacrossthefre-,T2,TR,TE(TE=TR/2)andtheflipangleα,butnotthefrequencyoffset,*paniedbycor-ticalactivationcanleadtophaseandmagnitudeincrease,:6:..???phafTR/(1/)*?(6)where?phaisthephasechangeand?*,°and25°-(-paredwithbSSFP(blueline).TheiSSFPsequenceshowsconstantmagnitudeandlinearphasealongthefrequencyforbothofhigh(a)andlow(b),theSSFPprofileisaveragedintothesizeofonesinglevoxelrepresentedbythegreenboxin(a)and(b).7:..-omsystem(SiemensMedicalSystems,Erlangen,Germany)with1CPtransmit/32channelreceiverheadcoil(NovaMedical,Cambridge,MA,USA).-,tenhealthysubjects(21-25yearsold,5males)werescannedusingtheiSSFPparisonwiththebSSFPandGRE(fivesubjectsforeach)sequencesrespec-tivelywithflipanglesof4°and25°.,a3DMPRAGEsequencewasperformedtoacquireT1-weightedstructuralimag-:oneax-ialobliqueslice(5mmthickness)wasorientedintheplanecoincidentwiththecalcarinesul-cus,FA=4°/25°,TR=(TE=TR/2),fieldofview(FOV)=220*220mm2,matrixsizeof128*128,**5mm3,bandwidth=358/130Hz/.,-designvisualstimulationwithdark-grayandlight--sblockswith28secstimulusfollowedby28secrest,andthetotalacquisitiontimeforbothtaskandrest--hairlo-8:..,aGREsequencewasperformedwiththeflipangleof8°(Ernstangle)forTE/TR=,inordertoinvestigatethesensitivitytopartialvolumeeffects,theiSSFPxandiSSFPzsequenc--planeresolutions(*,*,*,*).,-es,thetimecourseofphaseinaregionofinterest(ROI)inwhitematterwasusedtoregressplexsignalchanges,?I,werecalculatedfromvectorcomdifferenceofsignalsbetweentaskandrestingscans:?????IIiI*(7),eleratediSSFP(TE/TR=,SMSfactor=4,readoutband-width=162Hz/pixel)andtraditionalstandard2DGE-EPI(TE/TR=22/2000ms)wereper-formedusingasemanticprocessingtaskfMRItodetecttheanteriortemporallobeactivation[27].TheCAIPIRINHA(elera-tion)methodwasusedtosimultaneouslyexcitefourslicesthatwerephaseshiftedof0,pi/2,piand3/2*pi(0,FOV/4,FOV/2and3*FOV/4shiftinthephaseencodingdirectionrespec-tively).[28,29].Magnitudeimageswerereconstructedusingtheslice-GRAPPAtechniquewithakernelsizeof2*:**3mm3,FOVof220*220mm2,FAsof25°and85°,andTRsof3sand2sforiSSFPandGE-EPIscans,,e