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CerebralVenousThrombosisBarbaraSimons,GeertLycklamaaNijeholtandRobinSmithuisRadiologydepartmentoftheMedicalCentreHaaglandenintheHagueandtheRijnlandhospitalinLeiderdorp,theNetherlands脑静脉性栓塞形成•Introduction•Whentothinkofvenousthrombosis•Denseclotsign•Emptydeltasign•AbsenceofnormalflowvoidonMR•Venousinfarction•Imaginginsuspectedthrombosis•CT-venography•MR-venography•DSA•PitfallsinCT•ArachnoidGranulations•Mimickofdenseclotsign•Pseudoemptydeltasign•Wrongbolustiming•PitfallsinMRI•Hypoplastictransversesinus•Lowsignalintensityinthrombus•Flowvoidoncontrast-enhancedMR•Chronicduralsinusthrombosisandrelatedsyndromes•DAVF•ThrombosisandincreasedCSFpressure•VenousterritoriesPublicationdateOctober21,2010Cerebralvenousthrombosisisanimportantcauseofstrokeespeciallyinchildrenandyoungadults.Itismorecommonthanpreviouslythoughtandfrequentlymissedoninitialimaging.Itisadifficultdiagnosisbecauseofitsnonspecificclinicalpresentationandsubtleimagingfindings.Inthisarticlewewillfocuson:•Findingsonroutineimagingthatshouldmakeyouthinkofunsuspectedvenousthrombosis.•Howtoimagepatientsinsuspectedvenousthrombosis.•Pitfalls.此时应想到静脉栓塞可能•致密斑块征•空三角征•MR上正常流空征消失•静脉性脑梗塞疑似此病的成像方法•CT静脉成像•MR静脉成像•DSACT陷阱•蛛网膜颗粒•酷似致密凝块征•假性空三角征•错误的团注时间MRI陷阱•横窦发育不良•血栓内低信号强度•MR对比增强时的流空硬膜窦栓塞临床与相关综合征•DAWF（硬膜动静脉瘘）•栓塞和脑脊液压力增高静脉分布图静脉性脑梗塞是中风的重要原因，尤其是在儿童或年轻人。它比以前更常见而且常常在最初的成像中漏诊由于临床上缺少特征而且影像所见微妙，因而诊断困难这里主要讨论的内容：*提示可疑静脉性脑梗塞的常规影像学表现*疑为静脉性脑梗塞如何进一步进行影像学检查*陷阱Cerebralvenousthrombosisislocatedindescendingorderinthefollowingvenousstructures:•Majorduralsinuses:Superiorsagittalsinus,transverse,straightandsigmoidsinuses.•Corticalveins:•VeinofLabbe,whichdrainsthetemporallobe.•VeinofTrolard,whichisthelargestcorticalveinthatdrainsintothesuperiorsagittalsinus.•Deepveins:Internalcerebralandthalamostriateveins.•Cavernoussinus.Clinicallypatientswithcerebralvenousthrombosispresentwithvariablesymptomsrangingfromheadachetoseizureandcomainseverecases.Inneonatesshockanddehydrationisacommoncauseofvenousthrombosis.Inolderchildrenitisoftenlocalinfection,suchasmastoiditis,orcoagulopathy.Inadults,coagulopathiesisthecausein70%andinfectionisthecausein10%ofcases.Inwomen,oralcontraceptiveuseandpregnancyarestrongriskfactors.重要的解剖与临床脑静脉性栓塞多位于以下的静脉结构*主要静脉窦：上矢状窦、横窦、直窦和乙状窦。*皮质静脉：Labbe静脉，颞叶的引流静脉；Trolard静脉，为最大的皮质静脉，汇入上矢状窦。*深静脉：大脑内静脉和丘脑纹状体静脉。*海绵窦。*临床上，脑静脉栓塞可有多种症状，严重病例如头痛、癫痫、昏迷。*新生儿休克或脱水是脑静脉栓塞常见的原因。*在儿童，局灶性的感染如中耳炎或凝血障碍。*成人中，70%的病因为凝血障碍；10%源自感染女性，口服避孕药与妊娠也是其危险因素。WhentothinkofvenousthrombosisOnaroutinenon-enhancedMRorCTyoushouldthinkofthepossibilityofvenousthrombosiswhenyousee:DirectsignsofathrombusInfarctioninanon-arteriallocation,especiallyifitisbilateralandhemorrhagicCorticalorperipherallobarhemorrhageCorticaledemaVenousthrombosishasanonspecificpresentationandthereforeitisimportanttorecognizesubtleimagingfindingsandindirectsignsthatmayindicatethepresenceofthrombosis.Althoughthesefindingsareoftenpresentoninitialscans,theyarefrequentlydetectedonlyinretrospect.Clinicallypatientswithvenousthrombosisoftenpresentwithseizures,whichisnotasymptominpatientswithanarterialinfarction.什么情况下考虑静脉窦栓塞呢？？在常规的CT或MR平扫图像若有下面的表现应该想到静脉性脑栓塞可能：*静脉血栓的直接征象*脑梗塞非动脉性的常见部位，尤其是为双侧性、出血性*皮质或周围脑叶的出血*脑皮质水肿脑静脉血栓形成为非特异性的表现，因此，认识这些微妙的影像学的表现以及间接征象很重要，它可以指出血栓形成之存在。静脉血栓形成的病人在临床上常表现癫痫，但这不是动脉性脑梗塞病人出现的症状。尽管这些表现经常地出现在最初的扫描中，但却经常只是在回顾中发现这些异常。11、透明隔静脉12、丘脑纹状体静脉13、大脑内静脉14、大脑大静脉15、基底静脉24、直窦25、蝶顶窦26、海绵窦27、海绵间窦29、岩上窦30、岩下窦1、上矢状窦2、下矢状窦3、窦汇4、横窦5、乙状窦6、颈静脉球7、颈内静脉8、浅表皮层静脉9、静脉10、大脑中浅静脉Trolard静脉Labbe静脉Rosenthal基底静脉附加：正常解剖图与静脉栓塞的病理解剖示意图正常脑静脉窦示意图上矢状窦及脑静脉栓塞伴发的脑肿胀及损伤损伤的脑组织出血Denseclotsign（1）DirectvisualizationofaclotinthecerebralveinsonanonenhancedCTscanisknownasthedenseclotsign.Itisseeninonlyonethirdofcases.Normallyveinsareslightlydenserthanbraintissueandinsomecasesitisdifficulttosaywhethertheveinisnormalortoodense(seepitfalls).Inthesecasesacontrastenhancedscanisnecessarytosolvethisproblem.*致密凝块征（1）：CT平扫见到的脑静脉血栓的直接表现，出现率为1/3.*正常的脑静脉表现为密度较脑组织轻度高，但有些病例的正常与否判断确有困难（参见陷阱）。*CT增强扫描可准确地解决该问题。Denseclotsign(2)Visualizationofathrombosedcorticalveinthatisseenasalinearorcord-likedensity,isalsoknownasthecordsign.Anothertermthatisfrequentlyused,isthedensevesselsign.Denseclotsign(3)Ontheleftimagesofapatientwithahemorrhagicinfarctioninthetemporallobe(redarrow).Noticethedensetransversesinusduetothrombosis(bluearrows).*致密凝块征（2）：CT平扫见到的脑皮质静脉血栓的表现，呈线样或绳索样高密度影，即所谓绳索征（上图红箭）。也有称其为致密血管征。*致密凝块征（3）：CT平扫显示颞叶出血性梗塞（红箭）。*注意因血栓导致的左侧横窦高密度（蓝箭）。Twocasesofemptydeltasignduetothrombosisofthesuperiorsagittalsinus.Emptydeltasign（1）TheemptydeltasignisafindingthatisseenonacontrastenhancedCT(CECT)andwasfirstdescribedinthrombosisofthesuperiorsagittalsinus.Thesignconsistsofatriangularareaofenhancementwitharelativelylow-attenuatingcenter,whichisthethrombosedsinus.Thelikelyexplanationisenhancementoftherichduralvenouscollateralcirculationsurroundingthethrombosedsinus,producingthecentralregionoflowattenuation.Inearlythrombosistheemptydeltasignmaybeabsentandyouwillhavetorelyonnon-visualizationofthethrombosedveinontheCECT.Thesignmaybeabsentaftertwomonthsduetorecanalizationwithinthethrombus.空三角征（1）：*空三角征是增强CT检查的表现，用来描述上矢状窦栓塞。*该征由强化的三角组