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1、FULLPAPERMagneticResonanceinMedicine00:00–00(2015)SeparationofCellularandBOLDContributionstoT2*SignalRelaxationXialingUlrichandDmitriyA.Yablonskiy*0R2¼R2þR2:[1]Purpose:ThedevelopmentofareliableclinicaltechniqueforquantitativemeasurementsoftheparametersdefiningtheInotherwords,theparameterR2represen
2、tstheGREBOLDeffect,i.e.,oxygenextractionfraction(OEF),anddeoxy-signaldecayexpectedintheabsenceoftheBOLDgenatedcerebralbloodvolume,dCBV,isneededtostudyeffect.OneshouldkeepinmindthattheparameterR2brainfunctioninhealthanddisease.HereinweproposesuchinEq.[1],thatwecall“cellularcontribution”totheatechniq
3、uethatisbasedonawidelyavailablegradientR2*,generallydoesnotrepresentirreversible(withrecalledecho(GRE)MRI.respecttothespinecho)partoftheMRIsignaltrans-TheoryandMethods:OurmethodisbasedonGREwithmul-verserelaxation.Thiswouldonlybethecaseforasin-tipleechoesandamodelofsignaldecay(Yablonskiy,MRMglecompa
4、rtmenttissueinthestaticdephasingregime1998)thattakesintoaccountmicroscopiccellular(R2),meso-(2).Foramulticompartmenttissue,Eq.[1]shouldscopic(BOLD),andmacroscopic(backgroundfieldgradients)0bewrittenintheformofR2¼R2þR2;however,incontributionstotheGREsignaldecaywithadditionalaccount-cingforphysiolo
5、gicfluctuations.thismanuscriptweareusingtraditionalnotations,asResults:Using3TeslaMRI,wegeneratehighresolutionquan-definedinEq.[1](seefurthercommentsintheDiscus-titativemapsofR2*,R2,R20,andtissueconcentrationofsionsection).SeparatingtheMRIsignaldecayduetodeoxyhemoglobin,thelatterprovidingaquantitat
6、iveversionoftheBOLDeffect,thatisR20,fromR2*,couldprovideSWI.OurresultsforOEFanddCBVingraymatterareinaimportantinformationontissuemetabolicpropertiesreasonableagreementwiththeliteraturedata.whichisimportantforunderstandingnormalhumanConclusion:Theproposedapproachallowsgeneratinghighbrainoperation(3)
7、aswellasthepathophysiologyofresolutionmapsofhemodynamicparametersusingclinicalneurologicaldisorderssuchasstroke(4),Alzheimer’sMRI.Thetechniquecanbeappliedtostudysuchtissuesasdisease(5–7),Huntington’sdisease