中枢神经系统影像学诊断.ppt

第十八章中枢神经系统影像学诊断RadiologyofCentralNervousSystem,HebeiMedicalUniversity3rdHospital,中枢神经系统,脑脊髓,检查方法Modalities,头颅MRI头颅CTECT，emissioncomputedtomographySPECT,singlephotonemissioncomputedtomographyPET,positronemissiontomography脑血管造影,cerebralangiography经颅Doppler,transcranialdoppler，TCD头颅平片,plainfilm,最好的检查方法，为首选Firstchoice,检查方法Modalities,显示脑实质parenchymaMRI，MagneticResonanceImagingCT,ComputedTomography,检查方法Modalities,显示脑实质ParenchymaMRI是颅脑最好的检查方法firstchoice优点：advantage软组织分辨率最高任意面成像，有利于观察解剖关系检查序列多T1WI,T2WI,PDWI等缺点：disadvantage钙化、骨化、早期出血灶显示不如CT价格贵,检查方法Modalities,显示脑实质parenchymaCT是最常用的检查方法优点显示骨和钙化一般比MRI好显示早期出血比MRI好缺点对脑组织的分辨率不如MRI,检查方法Modalities,显示脑血管bloodvessel脑血管造影cerebralangiographyDSA，digitalsubstractiveangiographyMRA,magneticresonanceangiographyCTA,computedtomographyangiographyTCD,transcranialDoppler,DSAMRA,TranscranialDoppler，TCD,CTangiography,检查方法,显示脑功能brainfunctionDWI,diffusionweightedimagingPWI,perfusionweightedimagingBOLD,bloodoxygenationleveldependentECT,emissioncomputedtomography,DWIincerebralinfarct,AbsoluteCBF(A),D=timefortheloweredgeofthebolustoreachthetissue(B),Apatientwithrightcarotidocclusionandsmallrightsideinfarction(arrow),PerfusionImaging,BOLDtoshowthevisualcortex,检查方法,显示脑代谢brainmetabolismECTSPECTPETtracermostcommonis18FDG，analogueofglucoseMRS,SPECT,SinglepixelMRS,正常影像解剖normalimaginganatomy,平片plainfilm,CT扫描技术及正常影像解剖techniqueandnormalimaginganatomy,以听眦线为基线向上连续扫描912层层厚10mm,正常影像解剖normalimaginganatomy,MRI定位像(topography，scoutimage),T1WIaxial,T2WIaxial,T1WIcoronal,T2WIsagital,基本病变表现basicimagingsign,颅骨平片颅骨破坏颅板增厚颅板变薄骨折线,depressedskullfracture,skulldestruction,Thinningztable,Thicknessofskulltable,基本病变表现basicimagingsign,CT平扫密度改变densitychanges占位效应masseffect,spaceoccupyingeffect脑水肿brainedema,cerebraledema脑积水hydrocephalus脑萎缩brainatrophy,cerebralatrophy病灶的强化表现featuresaftercontrastinject,基本病变表现basicimagingsign,CT平扫密度改变高密度灶：钙化（肿瘤、血管畸形）、出血出血的演变低密度灶：坏死、水肿、液体、气体和脂类等密度灶：肿瘤、出血某一阶段混杂密度灶：多种成分病变，多见钙化：正常生理钙化、血管畸形、少枝胶质瘤等,等密度isodensity低密度水肿Lowdensity占位效应,高密度Highdensity占位效应,混杂密度mixeddensity,钙化calcification,占位效应spaceoccupyingeffect,masseffectCommondisease肿瘤tumor出血bleeding显著肿胀edemamanifestation中线结构移位displacementofmidlinestructures脑室与脑池移位变形脑室、脑池扩大enlargementofventricleandcistern脑沟变化fuci脑体积的改变enlargementofbrainvolume,脑水肿cerebraledema,炎症性水肿inflammatoryswelling感染infection出血bleeding挫伤contusion等血脑通透性增加increasingpermeabilityofBBB肿瘤tumor感染infection等,脑积水hydrocephalus,原因etiology脑积液产生和吸收失衡脑脊液循环通路障碍所致脑室系统异常扩大类型type交通性脑积水communicativehydrocephalus阻塞性脑积水obstructivehydrocephalus代偿性脑积水compensatoryhydrocephalus,梗阻性脑积水,正常脑压性脑积水Normalpressurehydrocephalus,脑萎缩cerebralatrophy,描述description各种原因引起脑组织减少而继发的脑室和蛛网膜下腔扩大分类type广泛性diffuse局限性local皮质cortex白质whitematter,增强扫描特征,机制mechanism血脑屏障通透性增加异常血管增生引起血流量增加常见类型commontype均一强化：脑膜瘤、生殖细胞瘤等环状强化：脑脓肿、脑转移瘤、星形细胞瘤等斑状强化：血管畸形、炎症等不规则强化：恶性胶质瘤等等,等密度，均匀强化Isodensity,homogeneousenhancement,环形强化Ring-rimenhancement,颅骨改变,增厚thickness变薄thin破坏destruction增生proliferation,giantcellreparativegranuloma,trauma,颅骨破坏,MRI基本病变表现basicMRIsign,与CT类似的表现thesimilarsignastoCT占位效应脑积水脑萎缩信号改变复杂，与CT密度改变不同长T1、长T2信号：肿瘤、脑梗死、炎症等脑脊液信号：囊性变、囊肿（FLAIR序列变黑）短T1、长T2信号：脂肪、黑色素瘤等无信号：钙化、晚期疤痕组织血管流空信号：多为无信号,MRI基本病变表现,水肿edemaT1WI为低信号lowsignalT2WI为略高信号slightlyhighintensity出血bleeding信号变化复杂thechangeofsignaliscomplex,长T1、长T2病灶，肿瘤,水肿edema,钙化无信号,囊性病灶cystic,T2WI高信号,MRI基本病变表现,增强环状均匀不均匀脑回状,脑内血肿(intracerebralhematoma),CT分期staging急性期acutestage1周高密度hyperdensity周围水肿surroundingedema吸收期absorptionstage2周2个月始于37天，密度逐渐减低囊变期cysticchangestage2个月水样低密度water-likedensity,MRI分期staging超急性期（Hyperacutehematoma）6小时T1WI等信号，T2WI为等信号急性期（Acutehematoma）7小时3天T1WI呈等信号，血肿内缘可见低信号强度的硬膜，T2WI呈低信号亚急性期和慢性期（Subacutehematoma）3天4周高信号(metahemoglobin)囊变期（Remotehematoma）4周液体信号周围有低信号（hemosiderin),血肿影像学表现Imagingpresentationofhematoma,Theevolutionofhematoma,Hyperacutehematoma,CTT1WIT2WI,CT,T2WI,Subacutetochronichematoma,Acutehematoma,GRE,T1WI,常见疾病诊断commondiseaseofCNS,脑外伤traumaofbrain脑血管病cerebraovasculardisease脑梗死cerebralinfarction脑出血cerebralhemorrhage脑肿瘤cerebraltumor,脑外伤traumaofbrain,CT为首选firstchoice显示骨折、早期出血好方便快速多螺旋可快速形全身检查MRI的适应症indicationCT检查阴性亚急性期慢性期平片已少用CT未普及的地区,脑外伤traumaofbrain,脑挫裂伤cerebralcontusion脑内血肿intracerebralhematoma硬膜下血肿subduralhematoma硬膜外血肿epiduralhematoma蛛网膜下腔出血subarachnoidhemorrhage,脑挫裂伤,名词的含义脑挫伤cerebralcontusion脑内散在出血灶，静脉淤血、脑血肿和肿胀脑裂伤lacerationofbrain伴有脑膜、脑或血管撕裂发病部位location着力点附近coupsite着力点对冲部位contrecoup病理pathology脑水肿坏死液化散在小出血点,脑挫裂伤,CT低密度病灶内散在斑点状高密度出血灶边缘模糊ill-definedrim占位效应masseffectMRI脑水肿T1WI呈低或等信号T2WI高信号出血bleeding表现与血肿期龄有关,Thereisafocalareaofhaemorrhagiccontusionintherightfrontallobe,withsurroundinglowdensityduetoinfarctionoroedema.Thisisafrequentlocationforacontrecoupinjuryfollowingablowtothebackofthehead.,弥漫性轴索损伤diffuseaxonalinjury,DAI,其他名称synonymy剪切伤shearinjury机制mechanism头受到旋转暴力致大脑绕中轴发生旋转运动白质、灰白质交界区、胼胝体、脑干及小脑等受到剪切力损伤弥漫性轴索断裂、点片状出血和水肿临床clinicalfeatures伤后意识立即丧失，多数立即死亡部分持续昏迷，后果严重,弥漫性轴索损伤diffuseaxonalinjury,Thisimagedemonstratesasmallpetechialhaemorrhageinatypicallocationatthegrey-whitematterinterface(arrow).Asisoftenthecase,thereweremultiplesuchlesionsonotherslices,硬膜下血肿subduralhematoma,出血部位location硬脑膜与蛛网膜之间发生率incidence颅脑外伤的56临床clinicalfeatures急性硬膜下血肿多与脑挫裂伤同时存在症状重慢性硬膜下血肿轻微头痛有或无明确外伤史,Epiduralspace,subiduralspace,Duralmatter,硬膜下血肿subduralhematoma,颅骨下方新月形高密度影占位效应等密度硬膜下血肿低密度硬膜下血肿,硬膜外血肿epiduralhematoma,部位location颅骨与硬膜之间发生率incidence占颅脑外伤的23临床clinicalfeatures急性：85亚急性：12慢性:少见,硬膜外血肿epiduralhematoma,颅板下梭形或半圆形高密度影多位于骨折附近不跨越颅缝,蛛网膜下腔出血subarachnoidhemorrhage,颅内血管破裂进入蛛网膜下腔病因etiology外伤trauma自发性spontaneously动脉瘤51高血压动脉硬化15动静脉畸形6%,临床clinicalfeatures好发年龄：3040岁三联征剧烈头痛脑膜刺激征血性脑脊液,蛛网膜下腔出血subarachnoidhemorrhage,蛛网膜下腔出血,脑血管病cerebrovasculardisease,脑出血intracerebralhemorrhage脑梗死infarctofbrain动脉瘤aneurysm血管畸形vascularmalformation,脑出血intracranialhemorrhage,病因etiology高血压hypertensiveintracerebralhemorrhage占40动脉瘤破裂脑血管畸形出血出血性脑梗死外伤脑肿瘤血液病等,高血压性脑出血hypertensiveintrcerebralhemorrhage,机制微小动脉瘤破裂脑血管玻璃样变好发部位predominatedlocation基底节、丘脑、脑桥和大脑半球白质内易破溃入脑室并发症complications脑水肿脑组织受压坏死,脑出血intracranialhemorrhage,脑内血肿,破入脑室,破入蛛网膜下腔,脑积水,脑梗死cerebralinfarction,原因etiology脑血栓形成thrombosis脑栓塞embolic血压过低lowbloodpressure发病率incidence为脑血管病首位,脑梗塞？,脑梗死cerebralinfarction,Pathology缺血性脑梗死ischemicinfarction出血性脑梗死hemorrhageinfarction腔隙性脑梗死lacunarinfarction好发于基底节区、脑干、小脑等病灶大小：515mm,脑梗死,CT低密度灶，其部位和范围与闭塞血管供血区一致，可有占位效应23周时可出现“模糊效应（foggingeffect）”增强：脑回样强化12个月形成边界清楚的低密度囊腔,脑梗死CT演变过程,024hrnormalorsubtlehypodensitysulcaeffacement17daysMasseffect(peakat34days)Daystomonths/yearsHypodensity18weeksContrastenhancementWeekstoyearsAtrophy,脑梗死,MRI显著优于CT急性期acutephase和超急性期superacutephaseDWI,PWI6hours传统MRI，FLAIR8hours亚急性期subacutephase慢性期Chronicphase,T1WIT2WIFLAIR,ADCmapDWIMRA,MultiphasicperfusionCTobtained3hoursafterthesuddenonsetofrighthemiparesisandaphasiaina76-year-oldwoman.F:2daysfollow-up,T1WI,T2WI,DWI,Male,60yearsoldOnset6hours,血管畸形vascularmalformation,为胚胎期血管的发育异常，分为动静脉畸形arteriovenousmalformation,AVM静脉畸形venousmaformation毛细血管扩张症capillarytelangiectasia海绵状血管瘤cavernoushemangioma等,动静脉畸形(AVM),CT不规则混杂密度灶钙化斑点或弧线形强化无水肿和占位效应不敏感,Male,65yr,动静脉畸形（AVM）,MRI扩张流空的畸形血管团邻近脑质：混杂低信号（hemosiderin）非常敏感,Male,48yr,Male,48yr,海绵状血管瘤cavernoushemangiomaM，31yr,颅内动脉瘤intracranialaneurysm,描述为血管的局限性扩张病因先天性80后天性20常见年龄predominatedonsetage3060yearsoldPredominatedlocationInternalcarotidartery90%Vertebralandbasilararterysystem10%并发症蛛网膜下腔出血,ThewhitearrowontheblackcardmarksthesiteofarupturedberryaneurysminthecircleofWillis,ThecircleofWillishasbeendissected,andthreeberryaneurysmsareseen.,脑肿瘤Braintumor,概况恶性胶质瘤glioma4050转移瘤metastasis3.1912.92%良性脑膜瘤meningioma1520垂体瘤pituitaryadenoma10%颅咽管瘤craniopharyngioma听神经瘤acousticneurinoma,脑肿瘤Braintumor,胶质瘤（glioma）星形细胞瘤astrocytoma40%少突胶质细胞瘤oligodendroglioma515%室管膜瘤ependymoma髓母细胞瘤medulloblastoma48%,星形细胞瘤astrocytoma,临床clinicalfeatures局灶性或全身性癫痫发作为最重要表现神经功能障碍颅内压增高,星形细胞瘤astrocytoma,CT级低密度灶，分界清楚，占位效应轻，无或轻度强化级高、低或混杂密度，可呈囊性斑点钙化和瘤内出血形态不规则，边界不清占位效应和瘤周水肿明显不规则环形伴壁结节强化，或不均匀强化,星形细胞瘤,MRIT1WI稍低或混杂信号T2WI均匀或不均匀性高信号恶性程度越高，其T1、T2值愈长，囊壁和壁结节强化越明显,局灶性弥漫型星形细胞瘤（WHO2级）,间变型星形细胞瘤（WHO3级）F/68平扫瘤体内低信号及条状高信号，累及基底节及颞叶周围明显水肿，增强后明显不均匀强化,Oligodendroglioma,Male,43yr,脑膜瘤meningioma,sexpredomination,gender中年女性多见起源于originatedin蛛网膜粒帽细胞多居于脑外，与硬脑膜粘连好发部位location矢状窦旁、脑凸面、蝶骨嵴、嗅沟、桥小脑角、大脑镰或小脑幕等，与硬脑膜相邻部位少数：脑室、眼眶,脑膜瘤（meningioma）,大体病理grasspathology肿瘤包膜完整，多由脑膜动脉供血，血运丰富，常有钙化，少数有出血、坏死和囊变组织学分型histologictype上皮型纤维型过渡型砂砾型血管瘤型等15型,脑膜瘤meningioma