医学影像诊断学脑血管病及颅内感染.ppt

脑血管病及颅内感染,脑血管病HEMATOMAINCT血肿的CT表现,Inatially,highattenuation.higherattenuationthanbrainbutlessthanbone(35-80Hu).Overseveraldaystoweeks,gradualdecreaseinattenuation.Hypodensitytocysticcavity.,ACUTEHEMATOMA急性血肿mildedema轻度水肿,SUBACUTEHEMATOMA亚急性血肿,CHRONICHEMATOMA慢性血肿,HEMATOMAINMRI,Acute(deoxyhemoglobin)急性期（脱氧血红蛋白）T1WI:Isointensitytomildhypointense等到低信号T2WI:Veryhighhypointense高信号Earlysubacute(intracellularmethemoglobin)亚急性早期（细胞内高铁血红蛋白）TIWI:Increasinghyper-intensityT2WI:Hypo-intensityinitially,changingtoisointense,HEMATOMAINMRI,Latesubacute(Extracellularmethemoglobin)亚急性晚期（细胞外高铁血红蛋白）T1WI:Hyper-intensityT1WI高信号T2WI:Hyper-intensitycentrallyT2WI中心高信号Chronic(Hemosiderin-ladenmacrophagesremain)慢性期（含铁血黄素）Athin,hypointenserimappearsTIWI:Hypo-intensitydecreasesovertimeT2WI:Rimofhypo-intensityincreases,centralhyperintensitydecrease,leavingonlyalowsignalintensityscar,ACUTEHEMOTOMA:DEOXYHEMOGLOBIN,ACUTEHEMATOMA,SUBACUTEHEMOTOMA,CHRONICHEMATOMAHEMOSIDERIN慢性期（含铁血黄素）,CEREBRALINFARCTION脑梗塞,Themostcommonetiologyofcerebralischemiaorinfarctionintheadultisocclusionofanarteryresultingfromeitherthrombusformationorembolism,withatherosclerosisthemostcommonunderlyingcause在成人，脑缺血或脑梗塞最常见病因是动脉闭塞，通常是血栓或动脉粥样硬化。Carotidarterydiseaseisespeciallycommon颈动脉疾病尤其常见。,CEREBRALINFARCTION,ISCHEMICINFARCTION缺血梗死HEMORRHAGICINFARCTION出血性梗死形成LACUNARINFARCTION腔隙梗塞,Imagingappearance,CTisoftennormalinthefirstfewhoursofinfarctionorischemia,sometimesforupto24hours.在梗死或缺血的最初几个小时，CT上通常表现为正常，有时甚至至24小时。Subtleeffacementofsulcimaybeanimportantearlycluetoinfarction.脑沟的细微消失可能是梗死的重要征象。,Imagingappearance,SomeoftheveryearliestsignsofMCAorinternalcarotidarteryinfarctiononCT.A.Lossoftheinsularstripofgraymatter(lossofgray-whitematterdistinction)B.LowattenuationintheipsilateralcaudateheadiftheperforatingarteriesarealsoaffectedC.AhighattenuationMCA,representingclotwithintheartery,Imagingappearance,Withtime,thereisincreasinglywell-definedlowattenuationinanareaofinfarctionbecauseofcytotoxicandvasogenicedema.Masseffect占位效应Thromboticinfarctionsofteninvolvealargevasculardistribution,embolicinfarctionsusuallyinvolveonlyaportionofamajorarterialterritory.Thetypicalvasculardistribution,oftenwedge-shapedandextendingtothecortex.,Imagingappearance,MRIismoresensitivethanCTforearlychangesofinfarction,butinthefirstfewhoursaftervascularocclusion,MRIalsomayappearnormal.DWI,PWImayprovideearlierevidenceofinfarction.对梗死的早期变化MRI较CT敏感，但是在血管闭塞最初的几个小时，MRI也可是正常的。DWI，PWI能提供更早的梗死证据。T1WI-lowsignalintensity低信号强度T2WI-highsignalintensity高信号强度FLAIR-highsignalintensity高信号强度,Lossoftheinsularstripofgraymatter,Subtleeffacementofsulci脑沟的微小消失,ACUTEINFARCTIONLOWDESITYandMASSEFFECT低密度和占位效应,SUBACUTEINFARCTIONLOWDENSUTYANDGYRIFORMENHANCEMENT,CHRONICINFARCTIONLOWDENSUTYandATROPHY,ACUTEINFARCTIONLONGT1、LONGT2andMASSEFFECT,T1WIT2WI,Flow-voideffect流空效应,CHRONICINFARCTION,GYRIFORMENHANCEMEMT,HEMORRHAGICINFARCTION出血性梗死形成,LACUNARINFACTION腔隙性梗死,hyperacuteinfarction梗死的超急性期,Acuteinfarctionshowsdecreaseddiffusion,chronicinfarctionshowingincreaseddiffusion.,ClinicalDWIcanidentifyacuteischemiclesionsthatarenotapparentonT2-WeightedMRimages.DWI能分辨出无法在T2上显示的急性缺血部分,INTRACRANIALINFECTION颅内感染,Thekeydiagnosticevidenceinsuspectedmeningitiscomesfromcerebrospinalfluidanalysisandculture,imaginghasanadjunctiveroleonly.脑膜炎的主要诊断依据是脑脊液分析和培养，图像仅仅是从属地位。Imagingmaydetectprocessessuchasabscessandencephalitis,maylocalizedfocalconditions,andmayhelpdemonstratetheprogressorresolutionofinfection图像可以显示脓肿和脑炎的征象，可帮助确定炎症的进展或消退。,INTRACRANIALINFECTION,Bacterialmeningitisiscommonandisassociatedwithseriousmorbidity.细菌性脑膜炎是常见的，有较高的死亡率。InflammatoryexudatesmayobscurethesubarachnoidcisternsonnoncontrastedCT,whereasmeningealenhancementmaybeobservedonCTorMRIfollowingintravenouscontrastmaterialadministration.(meningesthickening)在非对比的CT上炎性渗出物可以使蛛网膜下腔模糊，而给予静脉造影剂后脑膜增强就可以在CT或MRI上观察到（脑膜变厚）Lackofvisiblecontrastenhancementdoesnotexcludemeningitis.缺少可见的对比增强不能排除脑膜炎。,INTRACRANIALINFECTION,Imagingisimportantforevaluatingcomplicationsofmeningitis.影像学评估脑膜炎的并发症是重要的Communicatinghydrocephalus交通性脑积水Vasculitisorvasospasm血管炎或血管痉挛Ischemiaorinfarction缺血或梗死Subduralfluidcollection硬膜下积液Spreadofinfection(e.g.ventriculitis)感染扩散（脑室炎）,ABSCESS脑脓肿,Abscessofthebrainusuallybeginsascerebritis.CerebritisisinitiallydetectedasanareaoflowattenuationedemaonCTorofhighsignalintensityonT2WIandlowsignalintensityonT1WIMRI.Withtimecerebritisprogressestoabscess.脑脓肿通常起始于脑炎。脑炎被最早发现是在CT上是低密度的水肿区或在MRI上T2高信号影，T1低信号影。随时间推移，脑炎可发展为脑脓肿。,ABSCESS,Abscesswallisusuallyfairlythinanduniform,highdensityonCT,lowsignalintensityonMRI脓肿壁在CT上通常较薄，厚薄不甚不一致，呈高密度，在MRI上则呈低信号。Surroundingedema周围水肿Centralfluidattenuationorsignalintensity中心液化区呈水样信号强度Well-definedring-likepatternofenhancement边界清楚的环状强化,ABSCESS,Abscesswallisusuallyfairlythinanduniform,highdensityonCT.,ABSCESS,AbscesswallisusuallyfairlythinanduniformlowsignalintensityonMRI,Thedifferentialdiagnosisbetweencerebralabscessandcystictumor脑脓肿和囊性瘤的鉴别诊断,Multiformglioblastoma多形恶性胶质细胞瘤,Abscess脓肿,Bulkphase容积相,Hydrationlayer水,TUBERCULOUSMENINGITIS结核性脑膜炎,TUBERCULOUSMENINGITIS结核性脑膜炎,meningesthickening脑膜增厚并强化,CranialTrauma,Skull颅骨Penetratinginjury穿透性损伤Closedheadinjury闭合性头部损伤Hemorrhage出血Masseffect占位效应Shiftofintracranialstructure颅内结构的移位Secondaryeffects:继发效应infarction,hydrocephalus梗死，脑水肿,脑挫裂伤Gunshot枪弹伤,2.Intracranialhemorrhage颅内出血,Extra-axialhematomaSubduralhematoma硬膜下血肿Epiduralhematoma硬膜外血肿subarachnoidhemorrhage蛛网膜下腔血肿Intraventricularhemorrhage脑室内血肿Intra-axialhematoma,Hematoma血肿,Acutehemorrhageisusuallydense(bright)onCT.急性出血通常在CT上是高密度（亮的）OnMRI,thesignalofhematomaisdepended.而在MRI上，血肿信号是不确定的,3.EpiduralHematoma硬膜外血肿,Usuallyresultfromarterialbleeding,oftenfromlacerationofthemiddlemeningealarterybyasquamosaltemporalbonefracture.However,venousormixedsourcesalsomaycauseepiduralhematoma.通常来自动脉出血，常见的是颞骨鳞部骨折导致的脑膜中动脉破裂。但是静脉或者混合来源的也可以导致硬膜外血肿。,EpiduralHematoma硬膜外血肿,Extra-axialDonotcrosssutures不越过颅骨缝Usuallywithconvexmarginsoralentiformshape通常是凸面的或者是透镜状Masseffect占位效应Fracture骨折,EPIDURALHEMATOMA硬膜外血肿,lentiformshape凸透镜状,EPIDURALHEMATOMAS,Pneumatosis积气症,4.SubduralHematoma硬膜下血肿,Usuallyresultfromvenousbleeding通常来自静脉出血Themostcommonlocationisoverthecerebralconvexities最常见的位置是脑的凸面,SubduralHematoma硬膜下血肿,Extra-axialMaycrosssutures可以越过颅骨缝Usuallyextendingwidelyacrosstheconvexityandappearcrescentic(newmoon,luniform)通常越过凸面，显示为新月形Masseffect占位效应Skullfracture(sometimes)颅骨骨折（有时）,SUBDURALHEMATOMA,extendingwidelyacrosstheconvexity横跨脑的凸面,SUBDURALHEMATOMA,SUBADURALHEMATOMA,先天发育畸形DISPLA