简介：Cerebralischemianotonlycausespathologicalchangesintheischemicareasbutalsoinducesaseriesofsecondarychangesinmoredistalbrainregions(suchasthecontralateralcerebralhemisphere).Theimpactofsupratentoriallesions,whicharethemostcommontypeoflesion,onthecontralateralcerebellumhasbeenstudiedinpatientsbypositronemissiontomography,singlephotonemissioncomputedtomography,magneticresonanceimaginganddiffusiontensorimaging.Inthepresentstudy,weinvestigatedmetabolitechangesinthecontralateralcerebralhemisphereaftersupratentorialunilateralischemiausingnuclearmagneticresonancespectroscopy-basedmetabonomics.Thepermanentmiddlecerebralarteryocclusionmodelofischemicstrokewasestablishedinrats.Ratswererandomlydividedintothemiddlecerebralarteryocclusion1-,3-,9-and24-hourgroupsandtheshamgroup.~1Hnuclearmagneticresonancespectroscopywasusedtodetectmetabolitesintheleftandrightcerebralhemispheres.Comparedwiththeshamgroup,theconcentrationsoflactate,alanine,γ-aminobutyricacid,cholineandglycineintheischemiccerebralhemispherewereincreasedintheacutestage,whiletheconcentrationsofN-acetylaspartate,creatinine,glutamateandaspartateweredecreased.Thisdemonstratesthatthereisanupregulationofanaerobicglycolysis(shownbytheincreaseinlactate),aperturbationofcholinemetabolism(suggestedbytheincreaseincholine),neuronalcelldamage(shownbythedecreaseinN-acetylaspartate)andneurotransmitterimbalance(evidencedbytheincreaseinγ-aminobutyricacidandglycineandbythedecreaseinglutamateandaspartate)intheacutestageofcerebralischemia.Inthecontralateralhemisphere,theconcentrationsoflactate,alanine,glycine,cholineandaspartatewereincreased,whiletheconcentrationsofγ-aminobutyricacid,glutamateandcreatinineweredecreased.Thissuggeststhatthereisadifferenceinthemetabolitechangesinducedbyischemicinjuryinthecontral

简介：Introduction:Middleearvolume(MEV)isaclinicallyrelevantparameteracrossmiddleeardiseases.MEVvaluesbetweenthesetechniqueshaveneverbeforebeentestedforagreementinearswithperforatedtympanicmembranes(TMs).Methods:Middleearswereidentifiedfrom36patientsranging18e89yearsofagewithTMperforationswhounderwenttympanometryandtemporalbonecomputedtomography(CT)between2005and2015.MEVscalculatedbybothtympanometryandthree-dimensionalvolumereconstruction(3DVR)wereanalyzedforagreementusingBlandAltmanplots.Thedifferencesbetweentympanometricand3DVRMEVvaluesforeachgivenmiddleearwerecharacterizedacrossMEVquartiles(1?smallest;4?largest)andacrossincreasingstatesofmiddleeardiseaseusingKruskaleWallisandWilcoxontestingwithBonferronicorrection.Results:BlandAltmanplotsdemonstratedsignificantdisagreementbetweenMEVmeasurementtechniques.Differencesbetweentympanometric(T)and3DVRMEVvaluesweresignificantlygreaterwithincreasingaverage(i.e.(Tt3DVR)/2))MEVperlinearregression(p<0.0001).SignificancewasdemonstratedbetweenfourthandfirstaverageMEVquartiles(p?0.0024),fourthandsecondquartiles(p?0.0024),thirdandfirstquartiles(p?0.0048),andthirdandsecondquartiles(p?0.048).AbsoluteMEVdifferencewasnotsignificantlydifferentacrossvaryingstatesofmiddleeardisease(p?0.44).Conclusion:Statisticallyandclinicallysignificantdisagreementwasdemonstratedbetweentympanometricand3DVRMEVvalues.StudiesthatvaryinMEVestimationtechniquesmaybeexpectedtodemonstratesignificantlydifferentresults.ThesepreliminaryresultssuggestthatcliniciansshouldendeavortoseekfurtherconfirmationwheninterpretinghightympanometricMEVvalues.