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1、神经系统常见病的影像诊断 Imaging of Common CNS Diseases,T1-Weighted Images,Images whose design(timing of radio pulses and data readout)is to produce contrast between gray matter,white matter,and CSF,Three axial(transaxial or horizontal)slices:Spatial resolution is about 1 mm3Acquisition time for whole head is 5
2、-10 minutes,Zooming In,Can follow GM cortex fairly wellCan measure thickness of cortex and try to quantify vs age and/or disease and/or genesBright spots and lines:arterial inflow artifactLeads to idea of MRA=Magnetic Resonance Angiography=acquire images to make arteries stand out even moreHigher sp
3、atial resolution is possibleAt the cost of scan time,T2-Weighted Images,Often better than T1-weighting in detecting tumors and infarcts(usually radiologists look at both types of scans),T2*-Weighted Images,Designed to make venous blood(with lots of deoxy-hemoglobin)darker than normal tissue=venograp
4、hy,Output image,minIP 1 slice,minIP 2 slices,Images post-processed to enhance small effects,MRA,MRV,Brain Activation Map,Time series analysis results overlaid on T1-weighted volume,DTI Results,Unweighted(baseline b=0)image,Fractional Anisotropy(FA):Measures how much ADC depends on direction,FA Color
5、-coded for fiber directionality:x=Red y=Greenz=Blue,DWI,脑肿瘤brain tumor,常见颅内肿瘤common intracranial tumors,1、胶质瘤 glioma 2、神经鞘瘤和神经纤维瘤 neurinoma and neurofibroma 3、脑膜肿瘤 meningioma 4、淋巴瘤和造血系统肿瘤 lymphoma 5、生殖细细胞瘤 germinoma 6、鞍区肿瘤 tumors in sella and parasella region 7、转移性肿瘤 metastatic tumor,胶质瘤 glioma,星形细胞
6、肿瘤 astrocytoma 胶质母细胞瘤 glioblastoma少突胶质细胞瘤 oligodendroglioma室管膜瘤 ependymoma混合性胶质瘤 mixed glioma,星形细胞肿瘤 astrocytoma,星形细胞肿瘤是颅内常见肿瘤，好发于中青年和儿童，发病部位随年龄而异，儿童多见于后颅窝，成人发病者以幕上居多。按肿瘤分化程度分为四级（级）级肿瘤生长缓慢，边缘较清楚，占位及水肿均不明显，CT平扫表现为低密度，MRI T1WI呈低信号，T2WI呈均匀高信号，增强检查，无或轻度强化。,级肿瘤呈弥漫浸润生长，肿瘤轮廓不规则，境界不清，易发生坏死、出血和囊变。肿瘤最常发生于幕上(s
7、uper-tentorium)，可以累及中央区白质结构如胼胝体，或经中线延伸至对侧，呈蝶翼状(aliform)改变。肿瘤占位及水肿均明显。CT平扫常呈混杂低密度，MRI T1WI呈低信号或混杂信号，T2WI呈不均匀或均匀性高信号。增强多呈不规则花环状(race;ring)强化。,F,36，反复头痛2年，加重伴恶心、呕吐3天。,36 year-old female,repeat headache for 2 years,Symptoms aggravation with nausea and vomiting for 3 days,增强 with contrast injection,平扫 pl
8、ain scan,毛细胞星形细胞瘤,星形细胞瘤,F，51，间歇性呕吐一月余。,多形性胶质母细胞瘤,脑膜瘤meningeoma,脑膜瘤起源于蛛网膜的帽状细胞(arachnoidal codocyte)，为颅内常见肿瘤之一，好发于中青年女性。脑膜瘤为脑外肿瘤，血供丰富。可见于:大脑凸面convexity of brain、矢状窦旁parasaggital sinus、嗅沟olfactory groove、蝶骨嵴sphenoidal crest、鞍结节tuberculum sellae、桥小脑角cerebellopontine angle、天幕 tentorium等。,IMAGING FINDING
9、S,CT:平扫肿瘤呈等密度或略高密度，瘤周水肿少见，肿瘤钙化常见，局部颅骨可见增生(hyperplasia)、破坏或颅板(cranium;skull)增厚。增强扫描，病灶显著均匀强化，境界清晰。MR:T1WI呈等或略低信号，T2WI呈等或略高信号，信号均匀。水肿和占位一般不明显。肿瘤强化显著，有时可见“脑膜尾征”。So called“Tail sign of meninges”,血管造影：显示肿瘤由颈外动脉external carotid artery系统供血，肿瘤染色tumor stain明显。,F，42，头部外伤5天，头痛。,M，69，头痛，头晕一月余。4个月前曾因胃中分化腺癌手术。mod
10、erately differentiated adenocarcinoma,增强,垂体瘤hypophysoma;pituitary tumor,垂体瘤为颅内常见肿瘤，以3060岁女性常见。多数为垂体腺瘤，包括：泌乳素瘤prolactinoma、生长素瘤growth hormone、性激素瘤sex hormone、促肾上腺皮质激素瘤ACTH;adrenocorticotrophic hormone、促甲状腺素瘤等thyrotrophinoma，垂体瘤根据体积大小可以分为大腺瘤macroadenoma（直径 10mm）和微腺瘤microadenoma（直径小于10mm）。,微腺瘤征象（MR优于CT
11、）：CT增强可见低密度灶，MR动态增强可见低信号灶，形态改变：垂体上缘隆凸 protuberance;prominentia。垂体柄偏移 stalk hypophysial。垂体高度8mm。鞍底骨质吸收或鞍底下陷(introcession;)。,大腺瘤表现：蝶鞍扩大，鞍内肿块突向鞍上池，常在冠状位上呈沙钟状(mitriform)。CT平扫见病灶呈等密度或稍高密度影，边缘清楚，其内有时可见低密度影。肿瘤在T1WI呈低、等信号，T2WI呈等、高信号。注入造影剂后见明显强化，可均匀或不均匀。肿瘤可侵犯海绵窦cavernous sinus或蝶窦sphenoidal sinus，也可向上侵犯下丘脑hyp
12、othalamus。,F，35，闭经，溢乳3年。Amenorrhea and galactorrhea for three years,M，31，视力减退(hypopsia)一年，妻子不孕dysgenesia。体检：乳房女性化feminisation，肥胖obesity。,F,44，闭经amenorrhea，溢乳galactorrhea多年。,听神经瘤acoustic neuroma,听神经瘤起源于前庭蜗神经vestibulocochlear nerve，通常起自鞘膜sheath membran，也可直接起自神经（神经瘤、神经纤维瘤）。为桥小脑角最常见的肿瘤，好发于40-60岁。临床主要是听力
13、减退或消失hearing impairment or loss。肿瘤早期位于内听道acoustic meatus，以后长入桥小脑角池cerebellopontine angle。包膜完整，肿瘤容易坏死、囊变，少见出血、钙化。,CT平扫见桥小脑角池内等、低密度肿块，有占位，可压迫四脑室移位，水肿轻微。骨窗可见内听道扩大。增强扫描，肿瘤常呈不均匀明显强化。MRI是目前诊断听神经瘤最敏感的方法，呈长T1长T2信号改变，明显强化。,F，52，头晕，眼花耳鸣伴下肢活动障碍2月余。,Dizziness,dim eyesight，tinnitus and lower limb disability for
14、2 months，,脑转移瘤brain metastases,脑转移瘤占颅内肿瘤的20-40%，原发病灶可起源于肺、乳腺、胃、结肠、肾、甲状腺、睾丸testiculus、黑色素瘤melanoma及淋巴瘤、白血病等，以肺癌最多。多见于中老年人，50岁以上占80。,CT平扫呈不均匀等、低密度。MRI呈长T1长T2信号改变。病灶多发，常有坏死、囊变。灶周水肿明显。增强，肿瘤常呈不规则环形强化。肿瘤可同时侵犯脑膜、脑实质brain parenchyma及颅骨cranial bones。,F，40，右乳癌术后4年余，咳嗽、痰血bloody phlegm数月，胸部发现转移瘤。,M，61，渐起右侧肢体无力d
15、ebility半月。肺部发现肿块，脑部病灶手术病理：腺癌。,With contrast,Plein scan,Plein scan,With contrast,颅脑外伤craniocerebral trauma,脑挫裂伤contusion and laceration of brain,脑挫伤：脑组织水肿、肿胀，静脉淤血，病理上可见散在出血灶；如同时有脑膜、脑或血管撕裂，则为脑裂伤。二者合并则为脑挫裂伤。,M，12，头部外伤后，头痛，呕吐一天。,M，78，撞到后头痛一月，加重exacerbation伴小便失禁aconuresis 10天。,硬膜外血肿epidural hematoma;extr
16、adural hematoma,为血液在硬膜外间隙聚集，多由脑膜中动脉损伤所致。血肿多较局限confined;limited，呈梭形Fusiform或扁丘状flat，边界清楚，局部常有骨折。,M，26，骑摩托车与汽车相撞一小时。,硬膜下血肿Subdural hematoma,血液聚集于硬膜下间隙，沿脑表面广泛分布(extensive;widespread)，多为静脉窦或桥静脉(bridging vein)损伤所致。急性期（3天内)，血肿呈颅板下新月形(crescent-shaped;crescentiform;luniform)或半月形高密度影，常伴有占位及脑水肿。亚急性（4d-2W）或慢性期
17、（2W以上），血肿密度发生改变，可以出现高、等、低或混杂密度。,M，48，头部外伤2月余，现仍头痛。,M，72，双下肢不能站立3天。,左侧急性硬膜下血肿,右侧急性硬膜下积液,脑血管性病变cerebral vascular disease,脑血管疾病分类callsification of cerebrovascular disease,脑出血brain hemorrhage：主要是高血压性脑出血。最常见于基底节区，尤其是外囊、豆状核lenticula。脑梗塞cerbral infarction：1、缺血性脑梗塞 2、出血性脑梗塞 3、腔隙性脑梗塞动脉瘤aneurysm：多见于Willis环及其主
18、要分支。脑血管畸形cerebral vascular malformations：以AVM最常见。,M，70，高血压期，突发左侧肢体活动障碍6小时。,Focal ischemia,M，74，嗜睡，左侧肢体无力。有高血压史多年。,74 year old male,chief complaint:drowsiness and left limbs weakness.hypertension for meny years.,多发脑梗塞,78岁，女性，右侧肢体无力35 分钟。,T2 FLAIR,超急性脑梗塞,24 hours later,T2WI,MRA,From Mike Mosely(Stanford Radiology),出血性脑梗塞,出血性脑梗塞,基底节腔隙性梗塞,F，61，左侧头痛伴动眼神经麻痹2月余。oculomotor paralysis for two months,动脉瘤,Subarachnoid haemorrhage,Sudden onset of“the worst headache of my life”Mild nuchal rigidity,动静脉畸形,动静脉畸形,THANK YOU！,
