可逆性后部脑白质病.ppt

Posteriorreversibleencephalopathysyndrome(PRES),1,.,Posteriorreversibleencephalopathysyndrome(PRES)wasfirstreportedbyHincheyin1996.1.Itmayoccurduetoanumberofcausespredominantlymalignanthypertension,eclampsia,drugssuchastacrolimus,cyclosporine,autoimmunediseaseandpatientsundergoingorgantransplant.Afterthetimelyandeffectivetreatmentoftheclinicalmanifestationandneuroimagingchangescanfullyrecover,neurologicalsequelaegenerallydoesnotexist,2,Themostcommonclinicalsymptomsandsignsareheadache,alteredalertnessandbehaviorchangesrangingfromdrowsinesstostupor,seizures,vomiting,mentalabnormalitiesincludingconfusionandabnormalitiesofvisualperception.Seizuresmaybeginfocallybutusuallybecomegeneralized.,3,ClassicallyPRES：characterizedbyhyperintensityonT2-weightedandFLAIRimagesbilaterallyandsymmetricallyintheparietooccipitalregionswhichiscausedbysubcorticalwhitemattervasogenicedema.,4,AtypicalPRES：otherregionsofthebrainareinvolvedexcepttheparieto-occipitallobes.Includesbrainstem,cerebellum,basalganglia,andfrontallobes.Atypicalimagingappearancesincludecontrastenhancement,hemorrhage,unilateralityandrestricteddiffusiononMRIandinvolvementofgraymatter.,5,1、Themorepopulartheorysuggeststhathypertensionleadstofailureofautoregulation,subsequenthyperperfusion,andvasogenicedema.2、Theothertheorysuggeststhatvasoconstrictionandhypoperfusionleadstobrainischemiaandsubsequentvasogenicedema.Therelativepaucityofsympatheticinnervationsintheposteriorbrainresultsinincreasedsusceptibilitytohyperperfusionandvasogenicedemaduringacutebloodpressureelevations.Mostauthoritiesbelievethathypertensiveencephalopathyandeclampsiasharesimilarpathophysiologicmechanisms,Pathophysiology,6,A25-yearoldlady,primigravida；Onthe3rddayofpostpartumwithsuddenonsetofgiddiness,headache,vomiting,bilateralblurringofvisionfollowedbygeneralizedtonic-clonicseizure.HerBPwaswithinnormallimits.Bloodandurineroutineassayswerenormal,andnoproteinuriawasdetectedduringboththepregnancyandpuerperium.SheunderwentPersistentOccipito-posteriorpositionanddeliveredahealthymalebabyandherBPbothduringhersurgeryandpostpartumperiodwasnormal.,Case1,7,Fig.1Case1:MRIbrainFLAIR(A),T2(B),Diffusion(C)andapparentdiffusioncoefficient(D)showingchangesinbilateralcaudate,anteriorlimbofinternalcapsule,rightthalamusandbilateralparieto-occipitalsubcorticalwhitematter,Case1,8,Fig.2:Case1:FollowupMRIbrainT2(A)andFLAIR(B)sameareasinFig.1beingnormal,9,A21-yearoldlady,primigravidawith30weeksgestation；Onthe6thdayofpostpartumwithh/osuddenonsetofheadache,vomiting,bilateralblurringofvisionfollowedbyrecurrentgeneralizedtonic-clonicseizure.ShehadregularANCcheckupandherBPwaswithinnormallimits.Bloodandurineroutinetestswerenormal,andnoproteinuriawasdetectedduringboththepregnancyandpuerperium.SheunderwentemergencyLSCSforPROMdeliveredastill-birthandherBPbothduringhersurgeryandpostpartumperiodwas,10,Fig.3:Case2:MRIbrainT2(A),diffusion(B)andapparentdiffusioncoefficient(C)showingchangesinbilateralcaudate,globuspallidus,putamenandbilateralparietooccipitalsubcorticalwhitematter,Case2,11,Fig.4:Case2:FollowupMRIbrainT2(A),diffusion(B)andapparentdiffusioncoefficient(C)sameareasinFig.3beingnormal,12,FIGURE2.Atypicalpresentationofposteriorreversibleencephalopathysyndrome:Non-contrast(A)andpost-contrast(B)braincomputerizedtomographyindicatingahypodenselesionintheleftbasalgangliawithnocontrastenhancement;Brainmagneticresonanceimagingillustratingdiffusionrestrictionondiffusion-weightedimaging(C)andhighvaluesonapparentdiffusioncoefficient(D).,AtypicaPRES,13,FIGURE3.Atypicalpresentationofposteriorreversibleencephalopathysyndrome.Thebraincomputerizedtomographyrevealedglobalbrainedemawithalargeleftparietalhematoma(A),andhemorrhageinthepons(B);theaxialmagneticresonancetomogramalsodemonstratesatypicalpresentationoftheareaswithincreasedsignalintensitiesintheponsbrainstem(C).,14,Changesindiffusion-weightedmagneticresonanceimaging(DWI)andapparentdiffusioncoefficient(ADC)inposteriorreversibleencephalopathyiswelldocumented,andcansuccessfullydifferentiatePRESfromearlycerebralischemia.DWIisthestudyofchoiceinPREStodiscriminatebetweenvasogenicandcytotoxicedema,thereby,beinghelpfulasascreeningimagingmethodologyinthesettingofischemiccomplicationsofPRESinidentifyingirreversibletissuedamage.ADCmappingcanbeusefultoruleoutotherconditionsthatcanmimicPRES,suchascentralpontinemyelinolysis.,15,CONCLUSION,ItisofparticularimportancenottoexcludePRESasapossiblediagnosiswhenwehavetheappropr