SWI在颅内肿瘤中的应用.ppt

TheapplicationofSWIincerebraltumorSWI在颅内肿瘤中的应用,ZhaoShanshan,.,Introduction,Susceptibility-weightedimaging(SWI)isanovelmagneticresonance(MR)techniquethatexploitsthemagneticsusceptibilitydifferencesofvarioustissues,suchasblood,ironandcalcification.磁敏感加权成像（SWI）是一种利用组织磁敏感性差异产生图像的磁共振新技术，例如出血、铁和钙化,Introduction,SWIconsistsofusingbothmagnitudeandphaseimagesfromahigh-resolution,three-dimensionalfullyvelocity-compensatedgradientechosequence.SWI包括强度图和相位图，分辨率高且是三维高速补偿梯度回波Magnitudeimagesincreasetheconspicuityofthesmallerveinsandothersourcesofsusceptibilityeffects,whichisdepictedusingminimalintensityprojection(minIP)应用最小强度投影(minIP)技术对强度图像进行后处理，可以使静脉及其它磁敏感物质显示更清楚,Introduction,Susceptibility-weightedimagingisbetterabletodefinetheinternalarchitectureofthelesionincomparisontoconventionalMRsequencesaswellastoCET1-weightedimages磁敏感加权成像较常规MR序列如CE-T1加权成像，更好的显示病灶内部结构TheinternalarchitectureoftumorsvariessignificantlybetweenSWIandCET1imaging.SWI上和CET1图像显示肿瘤内的结构明显不同,Diversity,InternalarchitectureinCET1:determinedbythepresenceofnecrosis,cysts,andtumorboundariesCET1可显示的内部结构：坏死、囊变和肿瘤边缘InternalarchitectureinSWI:determinedmostlybybloodproductseitherfromvenousvascularcontentandmicro-hemorrhageinatumorSWI可显示的内部结构：主要由其内部的血液成分决定，脉管系统和瘤内微出血,Figure1.SWI(right)showsregionsofvenousvascularcontentandhemorrhageinatumor,whicharenotseenintheconventionalpostcontrastT1-weightedimage(left).图1.SWI(右)能显示常规T1增强图像(左)不能显示的瘤内微量出血和脉管系统,Fig.2Glioblastomamultiformae.aCEfat-suppressedaxialT1-weightedimagesshowingthenecroticheterogeneouslyenhancingmassintherightfrontallobe.bAxial2DGRE.cminIPSWI.NotethatthetumorneovascularityandhemorrhagesarebettershowninSWI3.SWIillustratesthehemoglobinbreakdownproductswithinthetumornotdetectedinconventionalimages,图2.多形性恶性胶质瘤.a.CE压脂轴位T1加权图像，右侧额叶可见含坏死的不均匀强化肿瘤；b.轴位2DGRE.c.minIPSWI.SWI可显示常规序列不能显示的血红蛋白降解产物,Value,Thisdifferenceinimageappearancecanallowrecurrenttumortobedistinguishedfrompostsurgicaltrauma.由于显示的图像不同，可区分术后出血和复发肿瘤WhilenecrosisisalsoafactorthatdeterminestheinternalarchitectureinSWIsequencesandT1sequences,lateenhancementonT1sequencesshowshomogenizationofsignalbetweennecroticandparenchymaltumorregions.其中T1和SWI上显示的瘤内坏死结构也是另一个影响因素，增强T1上肿瘤坏死和实质区域显示信号均匀OnCESWIimages,necroticregionsbecomehighinsignalcomparedtothelowsignaltumorparenchymaCESWI上坏死区域显示高信号，而肿瘤实质区域显示低信号,Figure3.Metastasisoflungadenocarcinomaintheleftfronto-parietalarea.CET1imaging(b),incomparisonwithprecontrastT1imaging(a),showstwoareasthatdidnotenhanceandlikelycorrespondtonecrosis.ThesameareasappearbrightonT2(notshown),supportingthathypothesis.CESWI(d),incomparisonwithSWI(c),showsanenhancementofthesameareas,suggestinglateenhancementduealeakageofcontrastagentbecauseCESWIwasperformedatleastsevenminutesaftertheCET1imaging.Thedarkmarginsofthetumorkeepthesamehypointensesignalaftercontrast,suggestingvenousvasculature,Figure3.额顶叶肺腺癌转瘤。CET1(b)与常规T1(a)对比，两个没有强化的区域是相应的坏死区域，在T2上信号显示更亮些(无图像)，能够证实这个假设。CE-SWI(d)与SWI(c)对比，同样的区域出现强化；由于CESWI是在CET1图像后至少几分钟后采集，故延迟强化是因为造影剂泄露造成。增强后肿瘤低信号区仍显示低信号，考虑是静脉脉管系统,Value,Susceptibility-weightedimagingalsoprovidesFLAIR-likecontrastbecausetheCSFissuppressedwhileedemaisenhancedrelativetothenormaltissue.ThisuniquecontrastcombinationofT2*effectsandedemawithinasingleimageallowsforimproveddetectionofspace-occupyinglesions.磁敏感加权图像可以显示液体反转序列显示的对比信号；因为与正常脑组织对比水肿信号被强化时，CSF信号被抑制。这种独特的对比结合单幅图像中T2*效应和水肿能够增加占位效应明显病灶的检出,Fig.4Primarycentralnervoussystem(CNS)lymphoma.aCEfat-suppressedaxialT1-weightedimages.Notetheintenselyenhancedspleniallesion.bAxialFLAIR.cminIPSWI,showingareasofhemorrhageandperilesionaedemawell图4.原发性中枢神经淋巴瘤。a.轴位CE-压脂T1加权图像。胼胝体压部病灶明显强化。b.轴位FLAIR；c.minIPSWI，能很好显示出血和病灶周围水肿区域,Value,PhaseimagesofSWIareneededtodifferentiatetumorvasculaturefromcalcificationssincebothshowhypointensityonminIPimages.由于脉管系统和钙化在minIP图上均显示低信号，SWI相位图可用于鉴别两者Calcium,beingdiamagnetic,showsnegativephase(inleft-handMRsystems)andistherebyhypointenseinphaseimages.钙化是逆磁性物质显示负相位(左手MR系统)，因此在相位图上显示低信号Tumorvasculatureduetothepresenceofincreaseddeoxy-HbshowsaparamagneticeffectwitharesultantpositivephaseonphaseSWIimages瘤血管内存在大量脱氧血红蛋白可产生顺磁性效应，在SWI相位上呈正相位,Fig.5Rightfrontaloligodendroglioma.aNECT.Notethecalcifiedcorticalbasedlesion(thickarrow).bAxial2DGREshowingthecalcification(thickarrow).cSWIminIPshowingthecalcification(thickarrow)andtheperipheralvessel(thinarrow),bothofwhicharehypointense.dCEfatsuppressedaxialT1-weightedimageshowingtheenhancingperipheralvein(thinarrow).eSWIphaseshowingthecalcification(thickarrow)andthedeoxy-Hbintheperipheralvein(thinarrow)showingoppositephaseinformation;consequently,thetwowillbedifferentiated,图5.右侧额叶少突胶质细胞瘤。a.NECT.显示皮层钙化(粗箭头)；b.轴位GRE序列显示钙化(细箭头)；c.SWIminIP图上显示钙化(粗箭头)和外周血管影(细箭头)；d.CE压脂轴位T1图像，显示周边血管强化影(细箭头)；e.SWI相位图显示钙化(粗箭头)和周边含脱氧血红蛋白的血管影(细箭头)，给出相反的信息，可对两者进行鉴别,Value,Thetumorgrowthdependonthepatho-vasifaction.Itexisitedafeaturewhichincludevesselstructurewithtachygrowthandmultiplemicrohemorrage,soSWIcanconducttomakegradeoftumor.由于肿瘤生长依赖病理血管形成，恶性肿瘤通常具有快速增长的血管结构和多发微量出血，因此应用SWI有助于肿瘤的分级High-gradetumorsoftenhaveahemorrhagiccomponent,whichmaybeusefulforstagingBloodproducts(deoxyhemoglobin,methemoglobin,ferritin,andhemosiderin)arewellrecognizedbytheSWIsequence.高级别肿瘤往往含有出血成分(脱氧血红蛋白、高铁血红蛋白、铁蛋白和含铁血黄素)，而SWI能很好的显示不同阶段的成分；,图6.男，49岁，右侧顶枕叶星形细胞瘤.a.T1FLAIR，可见右顶叶病灶内小血管数量少并且清晰度差；b和c.T2WI及T2FLAIR，显示病灶内小血管略增多；d.CE-T1WI，清晰显示了肿瘤实性强化部分，但其肿瘤血管与肿瘤实质无法区分；e.SWI-MinIP，显示小血管清晰，边界清晰，走行连续、迂曲；f.CE-SWI-MinIP，除了显示病灶内的小血管，还显示例肿瘤强化部分，低信号血管在高信号的肿瘤实质中尤为明显,Figure6Male,49yearsold,therightparietalandoccipitalastrocytoma.a.T1-FLAIR,therightparietallobelesionisnotedoflessbloodvesselswithinpoorresolution;bandc.T2WIandT2FLAIR,smallbloodvesselinthetumorslightlyincreased;d.CE-T1WI,clearlyshowedtheenhancedpartofthesolidtumor,butitisdifficulttodistinguishedthetumorbloodvesselsfromparenchymaoftumor;e.SWI-MinIP,clearlydemonstratedsmallbloodvessels,clearboundaries,runningcontinuously,tortuous;f.CE-SWI-MinIP,inadditiontorevealingthesmallbloodvesselswithinthelesion,alsoshowedenhancedportionoftumor,tumorbloodvesselswithlow-signalisparticularlyevidentcomparedwithparenchymawithhighsignal,Figure7female,27yearsold,therightfrontallobeastrocytomagrade；a-d,T1FLAIR,T2WI,T2FLAIR,CE-T1WI,conventionalserialcannotshowedthesignsoftumorhemorrhageandsmallbloodvessels;e-g.SWI-MinIP,CE-SWI-MinIPandCE-SWI-MaxIP,smallveinsandalsocannotdemonstratedsignsofsmallveinandbleeding,图7.女，27岁，右侧额叶星形细胞瘤级a-d，T1FLAIR,T2WI,T2FLAIR,CE-T1WI，常规序列未见肿瘤内出血和小血管征象；e-g.SWI-MinIP，CE-SWI-MinIP和CE-SWI-MaxIP,同样未见小静脉和出血征象,Value,Susceptibility-weightedimagingcanalsodifferentiateintraaxialtumorsfromextraaxialtumorsbydemonstratingtheshiftofvesselsaroundthemass磁敏感加权成像鉴别轴内和轴外肿瘤，主要观察对瘤周血管的受压移位情况,Fig.8Interhemisphericepidermoid.aAxial2DGRE,bSWIminIP.SWIprovidesmoreinformationastheleftthalamostriateandtheseptalveins(thinarrow)arebeingshiftedlaterallybythemass,图8.两半球间的表皮样囊肿a.轴位2DGRE，b.SWIminIP图SWI可显示肿瘤压迫左侧丘脑纹状体和脑中隔静脉向一侧移位,Value,SWIcanalsobeusedtodifferentiateacousticschwanommasfromcerebellopontineanglemeningiomaswiththeimproveddetectionofmicrohemorrhageswithinschwanommas,whicharenotobservedinthemeningiomasSWI可用于鉴别听神经鞘瘤和桥小脑较脑膜瘤，听神经鞘瘤可显示微出血，而脑膜瘤不出现,Fig.9Rightacousticschwannoma.aAxial2DGRE,bSWIminIP.Bothshowthemicrohemorrhageswithinthetumor,butSWIshowsthembetter.Notealsothewidenedrightinternalauditorymeatus(arrow),图9.右侧听神经鞘瘤.a.轴位2DGRE；b.bSWIminIP两者均可见瘤内微出血影，但是SWI显示更好。可见右侧内耳道增宽,Conclusion,Inthetermsofshowingthesmallveins,SWIT2WIandFLAIRT1WIandCE-T1WI在小静脉方面，SWIT2WI及FLAIRT1WI及CE-T1WI2.Intheternsofrevealinghemorrage,SWIshowsup,followedbyT2WIandFLAIR,T1WIandCE-T1WIshowstheworst.OnSWI,bleedingwithinthetumorshowedpatchylowsignal,aclearboundary,whichissuperiortoconventionalsequence,在出血方面，SWI显示最多，其