中樞神經(jīng)系統(tǒng)影像學(xué)診斷

第十八章

中樞神經(jīng)系統(tǒng)影像學(xué)診斷

RadiologyofCentralNervousSystem河北醫(yī)科大學(xué)第三醫(yī)院HebeiMedicalUniversity3rdHospital

中樞神經(jīng)系統(tǒng)腦脊髓檢查方法

Modalities頭顱MRI頭顱CTECT，emissioncomputedtomographySPECT,singlephotonemissioncomputedtomographyPET,positronemissiontomography腦血管造影,cerebralangiography經(jīng)顱Doppler,transcranialdoppler，TCD頭顱平片,plainfilm最好的檢查方法，為首選Firstchoice檢查方法Modalities顯示腦實質(zhì)parenchymaMRI，MagneticResonanceImagingCT,ComputedTomography檢查方法Modalities顯示腦實質(zhì)ParenchymaMRI是顱腦最好的檢查方法firstchoice優(yōu)點：advantage軟組織分辨率最高任意面成像，有利于觀察解剖關(guān)系檢查序列多T1WI,T2WI,PDWI等缺點：disadvantage鈣化、骨化、早期出血灶顯示不如CT價格貴檢查方法

Modalities顯示腦實質(zhì)parenchymaCT是最常用的檢查方法優(yōu)點顯示骨和鈣化一般比MRI好顯示早期出血比MRI好缺點對腦組織的分辨率不如MRI檢查方法Modalities顯示腦血管bloodvessel腦血管造影cerebralangiographyDSA，digitalsubstractiveangiographyMRA,magneticresonanceangiographyCTA,computedtomographyangiographyTCD,transcranialDopplerDSAMRATranscranialDoppler，TCDCTangiography檢查方法顯示腦功能brainfunctionDWI,diffusionweightedimagingPWI,perfusionweightedimagingBOLD,bloodoxygenationleveldependentECT,emissioncomputedtomographyDWIincerebralinfarctAbsoluteCBF(A)τD=timefortheloweredgeofthebolustoreachthetissue(B)Apatientwithrightcarotidocclusionandsmallrightsideinfarction(arrow)PerfusionImagingBOLD

toshowthevisualcortex檢查方法顯示腦代謝brainmetabolismECTSPECTPETtracermostcommonis18FDG，analogueofglucoseMRSSPECTSinglepixelMRS正常影像解剖

normalimaginganatomy平片plainfilmCT掃描技術(shù)及正常影像解剖

techniqueandnormalimaginganatomy以聽眥線為基線向上連續(xù)掃描9～12層層厚10mm正常影像解剖

normalimaginganatomyMRI定位像(topography，scoutimage)T1WIaxialT2WIaxialT1WIcoronalT2WIsagital基本病變表現(xiàn)

basicimagingsign顱骨平片顱骨破壞顱板增厚顱板變薄骨折線depressedskullfracture

skulldestructionThinningztableThicknessofskulltable基本病變表現(xiàn)

basicimagingsignCT平掃密度改變densitychanges占位效應(yīng)masseffect,spaceoccupyingeffect腦水腫brainedema,cerebraledema腦積水hydrocephalus腦萎縮brainatrophy,cerebralatrophy病灶的強(qiáng)化表現(xiàn)featuresaftercontrastinject基本病變表現(xiàn)

basicimagingsignCT平掃密度改變高密度灶：鈣化（腫瘤、血管畸形）、出血出血的演變低密度灶：壞死、水腫、液體、氣體和脂類等密度灶：腫瘤、出血某一階段混雜密度灶：多種成分病變，多見鈣化：正常生理鈣化、血管畸形、少枝膠質(zhì)瘤等等密度isodensity低密度水腫Lowdensity占位效應(yīng)高密度Highdensity占位效應(yīng)混雜密度mixeddensity鈣化calcification占位效應(yīng)spaceoccupyingeffect,masseffectCommondisease腫瘤tumor出血bleeding顯著腫脹edemamanifestation中線結(jié)構(gòu)移位displacementofmidlinestructures腦室與腦池移位變形腦室、腦池擴(kuò)大enlargementofventricleandcistern腦溝變化fuci腦體積的改變enlargementofbrainvolume腦水腫cerebraledema炎癥性水腫inflammatoryswelling感染infection出血bleeding挫傷contusion等血腦通透性增加increasingpermeabilityofBBB腫瘤tumor感染infection等腦積水hydrocephalus原因etiology腦積液產(chǎn)生和吸收失衡腦脊液循環(huán)通路障礙所致腦室系統(tǒng)異常擴(kuò)大類型type交通性腦積水communicativehydrocephalus阻塞性腦積水obstructivehydrocephalus代償性腦積水compensatoryhydrocephalus梗阻性腦積水正常腦壓性腦積水Normalpressurehydrocephalus腦萎縮cerebralatrophy描述description各種原因引起腦組織減少而繼發(fā)的腦室和蛛網(wǎng)膜下腔擴(kuò)大分類type廣泛性diffuse局限性local皮質(zhì)cortex白質(zhì)whitematter增強(qiáng)掃描特征機(jī)制mechanism血腦屏障通透性增加異常血管增生引起血流量增加常見類型commontype均一強(qiáng)化：腦膜瘤、生殖細(xì)胞瘤等環(huán)狀強(qiáng)化：腦膿腫、腦轉(zhuǎn)移瘤、星形細(xì)胞瘤等斑狀強(qiáng)化：血管畸形、炎癥等不規(guī)則強(qiáng)化：惡性膠質(zhì)瘤等等等密度，均勻強(qiáng)化Isodensity,homogeneousenhancement環(huán)形強(qiáng)化Ring-rimenhancement顱骨改變增厚thickness變薄thin破壞destruction增生proliferationgiantcellreparativegranulomatrauma顱骨破壞MRI基本病變表現(xiàn)

basicMRIsign與CT類似的表現(xiàn)thesimilarsignastoCT占位效應(yīng)腦積水腦萎縮信號改變復(fù)雜，與CT密度改變不同長T1、長T2信號：腫瘤、腦梗死、炎癥等腦脊液信號：囊性變、囊腫（FLAIR序列變黑）短T1、長T2信號：脂肪、黑色素瘤等無信號：鈣化、晚期疤痕組織血管流空信號：多為無信號MRI基本病變表現(xiàn)水腫edemaT1WI為低信號lowsignalT2WI為略高信號slightlyhighintensity出血bleeding信號變化復(fù)雜thechangeofsignaliscomplex長T1、長T2病灶，腫瘤水腫edema鈣化無信號囊性病灶cysticT2WI高信號MRI基本病變表現(xiàn)增強(qiáng)環(huán)狀均勻不均勻腦回狀腦內(nèi)血腫

(intracerebralhematoma)

CT分期staging急性期acutestage＜1周高密度hyperdensity周圍水腫surroundingedema吸收期absorptionstage2周～2個月始于3~7天，密度逐漸減低囊變期cysticchangestage＞2個月水樣低密度water-likedensityMRI分期staging超急性期（Hyperacutehematoma）＜6小時T1WI等信號，T2WI為等信號急性期（Acutehematoma）7小時～3天T1WI呈等信號，血腫內(nèi)緣可見低信號強(qiáng)度的硬膜，T2WI呈低信號亞急性期和慢性期（Subacutehematoma）3天～4周高信號(metahemoglobin)囊變期（Remotehematoma）≥4周液體信號周圍有低信號（hemosiderin)血腫影像學(xué)表現(xiàn)ImagingpresentationofhematomaTheevolutionofhematomaHyperacutehematomaCTT1WIT2WICTT2WISubacutetochronichematomaAcutehematomaGRET1WI常見疾病診斷

commondiseaseofCNS腦外傷traumaofbrain腦血管病cerebraovasculardisease腦梗死cerebralinfarction腦出血cerebralhemorrhage腦腫瘤cerebraltumor腦外傷traumaofbrainCT為首選firstchoice顯示骨折、早期出血好方便快速多螺旋可快速形全身檢查MRI的適應(yīng)癥indicationCT檢查陰性亞急性期慢性期平片已少用CT未普及的地區(qū)腦外傷

traumaofbrain腦挫裂傷cerebralcontusion腦內(nèi)血腫intracerebralhematoma硬膜下血腫subduralhematoma硬膜外血腫epiduralhematoma蛛網(wǎng)膜下腔出血subarachnoidhemorrhage腦挫裂傷名詞的含義腦挫傷cerebralcontusion腦內(nèi)散在出血灶，靜脈淤血、腦血腫和腫脹腦裂傷

lacerationofbrain伴有腦膜、腦或血管撕裂發(fā)病部位location著力點附近coupsite著力點對沖部位contrecoup病理pathology腦水腫壞死液化散在小出血點腦挫裂傷CT

低密度病灶內(nèi)散在斑點狀高密度出血灶邊緣模糊ill-definedrim占位效應(yīng)masseffectMRI腦水腫T1WI呈低或等信號T2WI高信號出血bleeding表現(xiàn)與血腫期齡有關(guān)Thereisafocalareaofhaemorrhagiccontusionintherightfrontallobe,withsurroundinglowdensityduetoinfarctionoroedema.Thisisafrequentlocationforacontrecoupinjuryfollowingablowtothebackofthehead.彌漫性軸索損傷

diffuseaxonalinjury,DAI其他名稱synonymy剪切傷shearinjury機(jī)制mechanism頭受到旋轉(zhuǎn)暴力致大腦繞中軸發(fā)生旋轉(zhuǎn)運動白質(zhì)、灰白質(zhì)交界區(qū)、胼胝體、腦干及小腦等受到剪切力損傷彌漫性軸索斷裂、點片狀出血和水腫臨床clinicalfeatures傷后意識立即喪失，多數(shù)立即死亡部分持續(xù)昏迷，后果嚴(yán)重彌漫性軸索損傷

diffuseaxonalinjuryThisimagedemonstratesasmallpetechialhaemorrhageinatypicallocationatthegrey-whitematterinterface(arrow).Asisoftenthecase,thereweremultiplesuchlesionsonotherslices硬膜下血腫

subduralhematoma出血部位location硬腦膜與蛛網(wǎng)膜之間發(fā)生率incidence顱腦外傷的5～6％臨床clinicalfeatures急性硬膜下血腫多與腦挫裂傷同時存在癥狀重慢性硬膜下血腫輕微頭痛有或無明確外傷史EpiduralspacesubiduralspaceDuralmatter硬膜下血腫

subduralhematoma顱骨下方新月形高密度影占位效應(yīng)等密度硬膜下血腫低密度硬膜下血腫硬膜外血腫epiduralhematoma部位location顱骨與硬膜之間發(fā)生率incidence占顱腦外傷的2～3％臨床clinicalfeatures急性：85％亞急性：12％慢性:少見硬膜外血腫epiduralhematoma顱板下梭形或半圓形高密度影多位于骨折附近不跨越顱縫蛛網(wǎng)膜下腔出血

subarachnoidhemorrhage顱內(nèi)血管破裂進(jìn)入蛛網(wǎng)膜下腔病因etiology外傷trauma自發(fā)性spontaneously動脈瘤51％高血壓動脈硬化15％動靜脈畸形6%臨床clinicalfeatures好發(fā)年齡：30～40歲三聯(lián)征劇烈頭痛腦膜刺激征血性腦脊液蛛網(wǎng)膜下腔出血

subarachnoidhemorrhage蛛網(wǎng)膜下腔出血腦血管病cerebrovasculardisease腦出血intracerebralhemorrhage腦梗死infarctofbrain動脈瘤aneurysm血管畸形vascularmalformation腦出血

intracranialhemorrhage病因etiology高血壓hypertensiveintracerebralhemorrhage占40％動脈瘤破裂腦血管畸形出血出血性腦梗死外傷腦腫瘤血液病等

高血壓性腦出血

hypertensive

intrcerebralhemorrhage機(jī)制微小動脈瘤破裂腦血管玻璃樣變好發(fā)部位predominatedlocation基底節(jié)、丘腦、腦橋和大腦半球白質(zhì)內(nèi)易破潰入腦室并發(fā)癥complications腦水腫腦組織受壓壞死腦出血intracranialhemorrhage腦內(nèi)血腫破入腦室破入蛛網(wǎng)膜下腔腦積水腦梗死

cerebralinfarction原因etiology腦血栓形成thrombosis腦栓塞embolic血壓過低lowbloodpressure發(fā)病率incidence為腦血管病首位腦梗塞？腦梗死

cerebralinfarctionPathology缺血性腦梗死ischemicinfarction出血性腦梗死hemorrhageinfarction腔隙性腦梗死lacunarinfarction好發(fā)于基底節(jié)區(qū)、腦干、小腦等病灶大?。?～15mm腦梗死CT低密度灶，其部位和范圍與閉塞血管供血區(qū)一致，可有占位效應(yīng)2～3周時可出現(xiàn)“模糊效應(yīng)（foggingeffect）”增強(qiáng)：腦回樣強(qiáng)化1～2個月形成邊界清楚的低密度囊腔腦梗死CT演變過程0～24hrnormalorsubtlehypodensity±sulcaeffacement1~7daysMasseffect(peakat3~4days)Daystomonths/yearsHypodensity1~8weeksContrastenhancementWeekstoyearsAtrophy腦梗死MRI顯著優(yōu)于CT急性期acutephase和超急性期superacutephaseDWI,PWI＜6hours傳統(tǒng)MRI，F(xiàn)LAIR＞8hours亞急性期subacutephase慢性期ChronicphaseT1WIT2WIFLAIRADCmapDWIMRAMultiphasicperfusionCTobtained3hoursafterthesuddenonsetofrighthemiparesisandaphasiaina76-year-oldwoman.F:2daysfollow-upT1WIT2WIDWIMale,60yearsoldOnset6hours血管畸形

vascularmalformation為胚胎期血管的發(fā)育異常，分為動靜脈畸形arteriovenousmalformation,AVM靜脈畸形venousmaformation毛細(xì)血管擴(kuò)張癥capillarytelangiectasia海綿狀血管瘤cavernoushemangioma等動靜脈畸形(AVM)CT不規(guī)則混雜密度灶鈣化斑點或弧線形強(qiáng)化無水腫和占位效應(yīng)不敏感Male,65yr動靜脈畸形（AVM）MRI擴(kuò)張流空的畸形血管團(tuán)鄰近腦質(zhì)：混雜低信號（hemosiderin）非常敏感Male,48yrMale,48yr海綿狀血管瘤cavernoushemangiomaM，31yr顱內(nèi)動脈瘤

intracranial

aneurysm描述為血管的局限性擴(kuò)張病因先天性80％后天性20％常見年齡predominatedonsetage30～60yearsoldPredominatedlocationInternalcarotidartery90%Vertebralandbasilararterysystem10%并發(fā)癥蛛網(wǎng)膜下腔出血ThewhitearrowontheblackcardmarksthesiteofarupturedberryaneurysminthecircleofWillisThecircleofWillishasbeendissected,andthreeberryaneurysmsareseen.腦腫瘤Braintumor概況惡性膠質(zhì)瘤glioma40～50％轉(zhuǎn)移瘤metastasis3.19~12.92%良性腦膜瘤meningioma15～20％垂體瘤pituitaryadenoma10%顱咽管瘤craniopharyngioma聽神經(jīng)瘤acousticneurinoma腦腫瘤Braintumor膠質(zhì)瘤（glioma）星形細(xì)胞瘤astrocytoma40%少突膠質(zhì)細(xì)胞瘤oligodendroglioma5~15%室管膜瘤ependy