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《Multi-Slice MRI of Rat Brain Perfusion During》由會(huì)員上傳分享，免費(fèi)在線閱讀，更多相關(guān)內(nèi)容在學(xué)術(shù)論文-天天文庫(kù)。
1、Multi-SliceMRIofRatBrainPerfusionDuringAmphetamineStimulationUsingArterialSpinLabelingAfonsoC.Silva,WeiguoZhang,DonaldS.Williams,AlanP.KoretskyWhenasinglecoilisusedtomeasureperfusionbyarterialbeusedtoquantitateperfusion.TheBlochequationscanspinlabeling,saturationofmacromolecularprotonsoccursbemodifi
2、edtoincludetheeffectsofperfusionsothatanyduringthelabelingperiod.Inducedmagnetizationtransfersequencethataltersarterialwatermagnetizationcanbecontrast(MTC)effectsdecreasetissuewatersignalintensity,usedtoderiveameasureofperfusion(5).reducingthesensitivityofthetechnique.Inaddition,MTCThelongitudinalfi
3、eldgradientusedduringthelabel-effectsmustbeproperlyaccountedforinacquiringacontrolimage.Thisforcestheimagetoasingleslicecenteredbe-ingperiodofanexperimenttomeasureperfusionallowstweenthelabelingplaneandthecontrolplane.Inthiswork,aselectivelabelingofarterialwaterspinsaslongasthetwo-coilsystemispresen
4、tedasawaytoavoidsaturationoffrequencyoffsetoftheFWirradiationismuchlargerthanmacromolecularspinsduringarterialspinlabeling.Thesys-thetissuewaterbandwidth.Thisconditionis,indeed,temconsistsofonesmallsurfacecoilforlabelingthearterialveryeasilyfulfilled.Forexample,asshowninFig.la,waterspins,andaheadcoi
5、lforMRI,activelydecoupledfromthelabelingplaneforratbrainperfusionislocatedinthethelabelingcoilbyusingPINdiodes.Itisshownthatnosignalneckabout2cmapartfromthedetectionslice.WhenalossoccursduetoMTCeffectswhenthetwo-coilsystemislongitudinalgradientof1Gauss/cmisused,thefre-usedforMRIofratbrainperfusion,e
6、nablingthree-dimen-sionalperfusionimaging.Usingthetwo-coilsystem,amulti-quencyoffsetatthelabelingplaneis8.5kHz,wellbe-sliceMRIsequencewasusedtostudytheregionaleffectsofyondthetissuewater'Hbandwidthof850Hzfora2-mmamphetamineonbrainperfusion.Amphetaminecausessig-thickcoronalslice.However,macromolecula
7、r'Hspinsnificantincreasesinperfusioninmanyareasofthebraincanhavelinewidthsaslargeas50kHz(6).Thus,ifaincludingthecortex,cingulate,andcaudateputamen,insinglecoilisusedtolabelthearterialspinsandtodetecta
