中枢神经系统影像学诊断.ppt

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1、第十八章 中枢神经系统影像学诊断Radiology of Central Nervous System,中枢神经系统,脑脊髓,检查方法Modalities,头颅MRI头颅CTECT，emission computed tomographySPECT,single photon emission computed tomographyPET,positron emission tomography脑血管造影,cerebral angiography经颅Doppler,transcranial doppler，TCD 头颅平片,plain film,最好的检查方法，为首选First choice,

2、检查方法 Modalities,显示脑实质 parenchymaMRI，Magnetic Resonance ImagingCT,Computed Tomography,检查方法 Modalities,显示脑实质 ParenchymaMRI是颅脑最好的检查方法 first choice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MR

3、I好缺点对脑组织的分辨率不如MRI,检查方法 Modalities,显示脑血管 blood vessel脑血管造影 cerebral angiographyDSA，digital substractive angiographyMRA,magnetic resonance angiographyCTA,computed tomography angiographyTCD,transcranial Doppler,DSA MRA,Transcranial Doppler，TCD,CT angiography,检查方法,显示脑功能 brain functionDWI,diffusion weigh

4、ted imagingPWI,perfusion weighted imagingBOLD,blood oxygenation level dependentECT,emission computed tomography,DWI in cerebral infarct,Absolute CBF(A),D=time for the lower edge of the bolus to reach the tissue(B),A patient with right carotid occlusion and small right side infarction(arrow),Perfusio

5、n Imaging,BOLD to show the visual cortex,检查方法,显示脑代谢 brain metabolismECTSPECTPETtracermost common is 18FDG，analogue of glucoseMRS,SPECT,Single pixel MRS,正常影像解剖normal imaging anatomy,平片 plain film,CT扫描技术及正常影像解剖technique and normal imaging anatomy,以听眦线为基线向上连续扫描912层层厚10mm,正常影像解剖normal imaging anatomy,MR

6、I定位像(topography，scout image),T1WIaxial,T2WIaxial,T1WIcoronal,T2WIsagital,基本病变表现basic imaging sign,颅骨平片颅骨破坏颅板增厚颅板变薄骨折线,depressed skull fracture,skull destruction,Thinningz table,Thickness of skull table,基本病变表现 basic imaging sign,CT平扫密度改变 density changes占位效应 mass effect,space occupying effect脑水肿 brain

7、 edema,cerebral edema脑积水 hydrocephalus脑萎缩 brain atrophy,cerebral atrophy病灶的强化表现 features after contrast inject,基本病变表现 basic imaging sign,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Low density占位效应,高密度High density占位效应,混杂密度 mi

8、xed density,钙化 calcification,占位效应space occupying effect,mass effectCommon disease肿瘤 tumor出血 bleeding显著肿胀 edemamanifestation中线结构移位 displacement of midline structures脑室与脑池移位变形脑室、脑池扩大 enlargement of ventricle and cistern脑沟变化 fuci脑体积的改变 enlargement of brain volume,脑水肿 cerebral edema,炎症性水肿 inflammatory s

9、welling感染 infection出血 bleeding挫伤 contusion等血脑通透性增加increasing permeability of BBB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communicative hydrocephalus阻塞性脑积水 obstructive hydrocephalus代偿性脑积水 compensatory hydrocephalus,梗阻性脑积水,正常脑压性脑积水Normal pressure hyd

10、rocephalus,脑萎缩 cerebral atrophy,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 white matter,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 common type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,homogeneous enhancement,环形强化Ring-rim e

11、nhancement,颅骨改变,增厚thickness变薄 thin破坏 destruction增生 proliferation,giant cell reparative granuloma,trauma,颅骨破坏,MRI基本病变表现basic MRI sign,与CT类似的表现 the similar sign as to CT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 edema T

12、1WI为低信号 low signalT2WI为略高信号 slightly high intensity出血 bleeding信号变化复杂 the change of signal is complex,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(intracerebral hematoma),CT分期 staging急性期 acute stage 1周高密度 hyperdensity周围水肿 surrounding edema吸收期 absorption stage 2周2个月始于37天

13、，密度逐渐减低囊变期 cystic change stage 2个月水样低密度 water-like density,MRI分期 staging超急性期（Hyperacute hematoma）6小时T1WI等信号，T2WI为等信号急性期（Acute hematoma）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（Subacute hematoma）3天4周高信号(metahemoglobin)囊变期（Remote hematoma）4周液体信号周围有低信号（hemosiderin),血肿影像学表现Imaging presentation of h

14、ematoma,The evolution of hematoma,Hyperacute hematoma,CT T1WI T2WI,CT,T2WI,Subacute to chronic hematoma,Acute hematoma,GRE,T1WI,常见疾病诊断common disease of CNS,脑外伤 trauma of brain脑血管病 cerebraovascular disease脑梗死 cerebral infarction脑出血 cerebral hemorrhage脑肿瘤 cerebral tumor,脑外伤 trauma of brain,CT为首选 first

15、 choice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trauma of brain,脑挫裂伤 cerebral contusion脑内血肿 intracerebral hematoma硬膜下血肿 subdural hematoma硬膜外血肿 epidural hematoma蛛网膜下腔出血 subarachnoid hemorrhage,脑挫裂伤,名词的含义脑挫伤 cerebral contusion脑内散在出血灶，静脉淤血、脑血肿和肿胀脑裂伤 laceration of brain伴有

16、脑膜、脑或血管撕裂发病部位 location着力点附近 coup site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-defined rim占位效应 mass effectMRI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,There is a focal area of haemorrhagic contusion in the right frontal lobe,with surrounding low density due to infa

17、rction or oedema.This is a frequent location for a contrecoup injury following a blow to the back of the head.,弥漫性轴索损伤 diffuse axonal injury,DAI,其他名称 synonymy剪切伤 shear injury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 clinical features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

18、轴索损伤 diffuse axonal injury,This image demonstrates a small petechial haemorrhage in a typical location at the grey-white matter interface(arrow).As is often the case,there were multiple such lesions on other slices,硬膜下血肿subdural hematoma,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 clinical features

19、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,Epidural space,subidural space,Dural matter,硬膜下血肿subdural hematoma,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 epidural hematoma,部位 location颅骨与硬膜之间发生率 incidence占颅脑外伤的23临床 clinical features急性：85亚急性：12慢性:少见,硬膜外血肿 epidural hematoma,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suba

20、rachnoid hemorrhage,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 clinical features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 subarachnoid hemorrhage,蛛网膜下腔出血,脑血管病cerebrovascular disease,脑出血 intracerebral hemorrhage脑梗死 infarct of brain动脉瘤 aneurysm血管畸形 vascular malformation,脑

21、出血 intracranial hemorrhage,病因 etiology高血压 hypertensive intracerebral hemorrhage 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 hypertensive intrcerebral hemorrhage,机制微小动脉瘤破裂脑血管玻璃样变好发部位 predominated location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 intracranial hemorrhage,脑内血肿,破入脑室,破入蛛网膜下腔,脑积水,

22、脑梗死 cerebral infarction,原因 etiology脑血栓形成 thrombosis脑栓塞 embolic 血压过低 low blood pressure发病率 incidence为脑血管病首位,脑梗塞？,脑梗死cerebral infarction,Pathology缺血性脑梗死 ischemic infarction出血性脑梗死 hemorrhage infarction腔隙性脑梗死 lacunar infarction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（foggi

23、ng effect）”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,024hr normal or subtle hypodensity sulca effacement17 daysMass effect(peak at 34 days)Days to months/yearsHypodensity18weeksContrast enhancementWeeks to yearsAtrophy,脑梗死,MRI显著优于CT急性期 acute phase 和超急性期 super acute phaseDWI,PWI 6 hours传统MRI，FLAIR 8 hours亚急

24、性期 subacute phase慢性期 Chronic phase,T1WI T2WI FLAIR,ADC map DWI MRA,Multiphasic perfusion CT obtained 3 hours after the sudden onset of right hemiparesis and aphasia in a 76-year-old woman.F:2 days follow-up,T1WI,T2WI,DWI,Male,60years oldOnset 6 hours,血管畸形vascular malformation,为胚胎期血管的发育异常，分为动静脉畸形 art

25、eriovenous malformation,AVM静脉畸形 venous maformation毛细血管扩张症 capillary telangiectasia海绵状血管瘤 cavernous hemangioma 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,48 yr,Male,48 yr,海绵状血管瘤cavernous hemangiomaM，31yr,颅内动脉瘤intracranial aneurysm,描

26、述为血管的局限性扩张病因先天性 80后天性 20常见年龄 predominated onset age3060 years oldPredominated locationInternal carotid artery 90%Vertebral and basilar artery system 10%并发症蛛网膜下腔出血,The white arrow on the black card marks the site of a ruptured berry aneurysm in the circle of Willis,The circle of Willis has been disse

27、cted,and three berry aneurysms are seen.,脑肿瘤 Brain tumor,概况恶性胶质瘤 glioma 4050转移瘤 metastasis 3.1912.92%良性脑膜瘤 meningioma 1520垂体瘤 pituitary adenoma 10%颅咽管瘤 craniopharyngioma听神经瘤 acoustic neurinoma,脑肿瘤 Brain tumor,胶质瘤（glioma）星形细胞瘤 astrocytoma 40%少突胶质细胞瘤 oligodendroglioma 515%室管膜瘤 ependymoma 髓母细胞瘤 medullo

28、blastoma 48%,星形细胞瘤 astrocytoma,临床 clinical features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

29、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,43 yr,脑膜瘤meningioma,sex predomination,gender中年女性多见起源于 originated in 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 grass pathology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 histologic type上皮型纤维型过渡

30、型砂砾型血管瘤型等15型,脑膜瘤meningioma,CT平扫 plain scan等或略高密度常见斑点状钙化广基底与硬脑膜相连边界清楚可有瘤周水肿颅板：增生或破坏增强扫描 enhancement均匀性显著强化,脑膜瘤meningioma,MRI平扫T1WI等或稍低信号T2WI等或高信号边缘清楚与正常脑组织间有时有脑脊液影增强扫描明显均匀强化脑膜尾症 dural tail sign,女 653月前出现反应迟钝，记忆力下降，左下肢无力,CT plain scan,T2WI,T1WI,T1WI,enhancement,Femal,61yr右下肢无力2年，加重2月,脑膜瘤侵犯颅骨,转移瘤metast

31、asis,易发人群 predominated population中老年人易发病部位 location顶枕区皮髓质交界处原发灶 primary lesionlung,breast,prostate,kidney,and so on,Metastasis of Brain,CT表现多发或单发结节 multipl or single nodule等或低密度 isodensity or low density出血时：高密度 hyperdensity瘤周水肿 surrounding edema结节或环形强化 nodular or ring enhancementMRI长T1、长T2信号,增强容易发现转

32、移瘤！,垂体腺瘤（pituitary adenoma）,功能性腺瘤泌乳素、生长激素、性激素和促肾上腺皮质激素瘤非功能性腺瘤微腺瘤：直径10mm病理包膜完整较大可坏死、囊变、出血，偶可钙化向四周侵犯临床：压迫症状:视力障碍、垂体功能低下、阳痿、头痛等内分泌症状：泌乳素、生长激素、促肾上腺皮质激素等,垂体腺瘤(pituitary adenoma),影像表现MRI为首选检查方法垂体向周围彭隆，特别向上彭隆垂体柄移位增强多均匀强化少数中心坏死CT必须增强扫描,Pituitary gland tumorMale,41yr,DSA,Cranial Metastasis of Hepatocellular Carcinoma,Hydatid cyst of the brain,