影像异常征象课件

影像异常征象： 神经科常见影像征象总结,李国良教授,虎纹与豹纹征,(A) 脑白质放射状低信号条纹构成虎皮纹。 （B）半卵圆区的低信号斑点构成豹皮纹。,异染性脑白质营养不良症,磨牙征 Joubert综合征,三明治征,“车轨征”(增强的管状高密度肿瘤与不增强的视神经之间的密度差异,轨道征用于鉴别视神经胶质瘤与视神经鞘脑膜瘤. 视神经胶质瘤无论何种生长类型,都与视神经紧密相连,因而肿瘤与视神经之间没有明确界限,表现为视神经-鞘结构均质性增大,没有可分辨的低密度视神经结构. 视神经鞘脑膜瘤起源于沿视神经鞘的蛛网膜上皮细胞,早期于硬膜下生长,包绕视神经,而不侵犯视神经,沿视神经生长,位于眶内、视神经管内、颅内视神经管开口者都可具轨道征表现,基底动脉包埋征,是指：脑干肿瘤可向前突入脑桥前池并包埋基底动脉，后者在和横轴位和矢状位上呈圆形或条状低密度或低信号影，为脑干肿瘤的特征性影像学表现。,脑膜尾症,束腰征 垂体大腺瘤向鞍上生长，冠状位上呈葫芦状，是因鞍隔束缚肿瘤之故，影像学上称为“束腰征”,“蜂窝状”强化征：颅内软骨瘤,影象学鉴别要点：如果出现下列征象，则可能提示“软骨肉瘤”的诊断。 1,高于脑膜瘤的T2信号； 2, 有混杂与病灶内的低信号的“软骨岛” 3,软脑膜屏障完好； 4,“蜂窝状”强化 5,乏血管（PWI或DSA）； 6,欠缺瘤周水肿； 7,没有血管流空。,弯曲条带样钙化征,弯曲条带样钙化表现为平扫图像内可见肿瘤内见弯曲条带状高密度钙化影。钙化从肿瘤小血管开始，沿肿瘤血管束及其周围肿瘤组织沉积，形成弯曲条带状结构，为少突胶质细胞瘤的特征性表现。 左侧额颞叶少突胶质细胞瘤，病变内见多发弯曲条带样钙化,脑回状或弯曲条带状钙化,结节硬化tuberous sclerosis，“烛泪征” 沿侧脑室的钙化灶,爆米花征、桑葚征,铁环征,铁环征在或磁敏感成像序列上，脑实质内病灶周边出现的低信号环，谓之铁环征，该低信号环随着时间的增加而逐渐增宽。铁环征是脑实质内海绵状血管瘤的表现，病灶周边低信号环为反复多次少量慢性出血病灶周围出现含铁血黄素沉积所致。 、显示脑实质内个高低混杂信号病灶，病灶周围环绕低信号环；、显示个病灶均为高信号，病灶周围铁环征较明显,牛眼征,动脉瘤阴阳八卦征,常春藤征,海蛇头征、“水母头”征,海蛇头征（“水母头”征）脑静脉畸形（脑发育性静脉异常）异常扩张的髓静脉引流入12 条粗大的引流静脉,形成“海蛇头”征,不伴有供血动脉和直接的动静脉短路。 DSA诊断要点：动脉相、毛细血管相正常，髓静脉扩张造影剂滞留，典型者表现为海蛇头征/“水母头”征。其实所谓“隐匿型血管畸形”中部分病例可能存在此种漏诊。MR增强对于脑发育性静脉异常诊断价值极大,水母头征The caput medusa sign,本征象是脑发育性静脉异常（DVA）在MR上的特征性表现 扩张的髓静脉呈辐射状引流向一支粗大的静脉，呈“海蛇头”样。,鼠尾征,新月征、双腔征、铅笔头征,束带征、绳索征,一产妇,头痛,反应迟钝,头颅CT及MRI示大脑大静脉及直窦血栓形成.伴丘脑水肿,空三角征（empty triangle sign或Delta征,静脉窦血栓形成，CT增强后血栓不强化,周边强化,可见到空三角征。 下图右侧为空三角征，左侧横窦为代偿性血流增加表现。,斑马纹征,Noncontrast axial head CT scan shows a subcortical hemorrhagic venous infarct in the right parietal region in a patient with a dense triangle or delta sign.,分水岭梗死的串珠样改变,颅内花瓣样病变,大脑中动脉高密度征的CT影像,A hyperdense-appearing cerebral artery on CT scan is indicative of occlusion due to thrombus formation. The area it supplies is at risk for ischemia. Occlusion of the internal carotid artery and middle cerebral artery has more adverse consequences due to the large cerebral mass that these arteries supply.,大脑后动脉高密度征的CT影像,豆状核模糊征 Obscuration of the lentiform nucleus sign,A 9-year-old child 5 hours after a traumatic bicycle accident with deteriorating mental status. (A) Emergent CT reveals loss of normal left lentiform nuclear attenuation (solid arrows) consistent with cytotoxic edema, as compared with the normal-appearing right lentiform nuclei (open arrows). (B) Follow-up CT confirms a left basal ganglia infarction.,岛带征 Insular ribbon sign,In a 70-year-old man with acute right-sided weakness, emergent CT reveals loss of the left insular ribbon (solid arrows), consistent with cytotoxic edema, as compared with the normal-appearing right insular ribbon (open arrows). Follow-up CT (not shown) showed a large left middle cerebral artery infarction.,弥散性脑白质病变 +MR异常流空,漩涡征-急性硬膜外血肿,靶征,可以见于： 1.转移瘤 2.寄生虫 3.结核瘤,黑靶征白靶征,脑猪囊尾蚴病平扫大多表现为小圆形囊性病灶，大小为，长、长信号，部分病灶在上黑色的低信号内见到点状高信号，即黑靶征；在上白色高信号内见到点状低信号，即白靶征。 脑猪囊尾蚴病存活期和退变死亡期，上猪囊尾蚴的头节表现为点状中高信号；上表现为比脑脊液信号低。 、可见多个散在的小圆形囊性病灶，表现为低信号，部分病灶在上黑色的低信号内可见到点状高信号，即黑靶征；、局部放大图，在上白色高信号内见到点状低信号，即白靶征。,隧道征-脑型肺吸虫病的MRI表现,肺吸虫的成虫与幼虫均有窜扰的习性,侵犯中枢神经系统亦较常见。幼虫可通过纵隔，沿颈内动脉上行至颅内，侵犯附近脑组织，早期病变多位于枕、颞叶部，随后幼虫继续向四周游走，侵入白质、内囊、底节、顶叶、额叶、脑室及对侧大脑等处，在脑组织中移行造成隧道状损伤。,CID影像花边征,CID影像曲棍球,丘脑枕征pulvinar sign,33-year-old woman with variant Creutzfeldt-Jakob disease. Axial fluid-attenuated inversion recovery MR image shows high signal intensity bilaterally in pulvinar and medial aspects of thalamus (arrows).,病毒性脑炎-刀切征,CT平扫呈片状不规则低密度，但在早期可以正常。 MR可以发现很早期病变，MRI检查呈T1低信号，T2高信号，豆状核常不受侵犯，病变区豆状核之间界线清楚,凸面向外,如刀切样,此点被许多学者认为是本病最具特征性的表现,MRI of acute middle carotid artery (MCA) stroke on MRI at 12 hours postictus. T2-weighted image shows mild hyperintensity of the middle carotid artery territory (arrows). Noncontrast T1-weighted image demonstrates early stroke changes with effacement of cortical sulci in the MCA territory associated with swelling and mild hypointensity of the cortical ribbon (arrows). After contrast (gadolinium) administration, intravascular enhancement is present, indicating sluggish flow in the ischemic zone (arrows).,openring sign,开环征对脱髓鞘假瘤具有高度特异性 强化意味着活动病灶有BBB破坏，脱髓鞘一旦完成，强化消失。 openring sign 示亚急性期,黑洞征,Axial T1WI (Fig. 1) demonstrates an abnormal signal intensity lesion in the right corona radiata with surrounding vasogenic edema. Corresponding axial T2WI (Fig. 2) suggests that the lesion is predominantly necrotic and is surrounded by a hypointense rim. Contrast-enhanced axial T1WI (Fig. 3) demonstrates an incomplete ring of enhancement. Apparent diffusion coefficient (ADC) map (Fig. 4) demonstrates restricted diffusion along the enhancing region and likely reflects the advancing demyelinating front. Diagnosis: Tumefactive demyelinating lesion,multiple sclerosis,Schilders disease,葱头样征、标靶征,Balo同心圆硬化临床症状轻重程度并非为诊断关键,而MRI的典型改变大脑白质可见急性期双重构造病变(friedegg-like,煎蛋样)及亚急性期的同心圆层状改变是诊断的重要指标。 但同心层病变的形状取决于受累的部位，若靠近脑皮层或皮层下，则可能呈花叶样或玫瑰花样，亦可呈平行线状 增强时若发现有同心层状条带强化就应考虑此病,病例特点： 1 49岁,中年女性，急性起病。 2 右下肢无力10天，反应迟钝3天。初为发作性症状，入院前三天始有认知功能障碍。 3 查体：体温血压正常，神志清楚，计算力及理解力差，右侧轻偏瘫。右侧病理征阳性。 4 辅助检查：脑脊液正常。颅脑MRI ：050404日T1略低信号，T2较均匀高信号，较T1像显示病灶范围大，Flair序列高信号。增强MRI病灶边缘强化。5月27日MRI病灶增加，较原有病灶扩大。信号无明显变化。MRA看不出明显异常 病检结果是同心圆性硬化,蝙蝠翼征,蝙蝠翼征,Alzheimer病的大象征：双侧颞叶萎缩，海马沟明显突出，貌似大象,“蝴蝶征” (butterflysign)与 “半蝴蝶征” (semibutterfly sign),“蝴蝶征” 是原发于胼胝体的胶质瘤经胼胝体辐射侵及两侧大脑半球，或一侧大脑半球胶质瘤经胼胝体辐射侵及对侧大脑半球的表现 “半蝴蝶征” 是一侧大脑半球的胶质瘤经胼胝体辐射侵及胼胝体，或胼胝体胶质瘤经胼胝体辐射侵及一侧大脑半球的表现。,虎眼征 Hallervorden-Spatz病,eye of the tiger,猫眼征：一氧化碳中毒性迟发性脑病,运动神经元病的酒杯症 t2高信号为受损的锥体束，其走形酷似酒杯,corticospinal tract (CST) degeneration,Figure 1: Axial DW image shows hyperintensities within the corticospinal tracts of the posterior limb of the internal capsules (arrows). On the FLAIR sequence there is high signal within the precentral gyri of bilateral hemispheres (arrows). Figure 2. Coronal T2-weighted image shows hyperintensities along the corticospinal tracts (arrows).,corticospinal tract (CST) degeneration,Hyperintensity in the Cortical and subcortical precentral gyral at T2-weighted MR imaging is described in amyotrophic lateral sclerosis (ALS).,corticospinal tract (CST) degeneration,corticospinal tract (CST) degeneration,Axial and coronal FLAIR images of patient 4 show high signal intensity in the posterior limb of both internal capsules (white arrows, A) and along the corticospinal tracts (white arrowheads, B).,corticospinal tract (CST) degeneration,Fig.1. 39-year-old man with bradykinesia and ataxia. Axial FLAIR image reveals symmetric abnormal signal in optic radiations (short arrow) and posterior limbs of internal capsule (long arrow). Anterior limb of internal capsule was spared in all patients. Fig. 2. 32-year-old man with dysarthria, ataxia, and bradykinesia after inhalation of heroin vapor. Axial T2-weighted MR image shows symmetric signal hyperintensity in posterior limbs of internal capsule and optic radiations. Fig. 3. Note abnormal signal in pons involving corticospinal tracts (white arrow),Wallerian degeneration,degenerative changes which occur in the distal axonal segments and their myelin sheath secondary to proximal axonal injury or death of the cell body. This process is observed in the pyramidal tract following cerebral infarct, trauma to the motor cortex or in neurodegenerative diseases like amyotrophic lateral sclerosis. Within 5 to 12 weeks after acute insult, the Wallerian degeneration of the pyramidal tract can be detected as a high signal intensity area on T2-weighted MR scans (Fig.1). Ipsilateral brain stem atrophy, well seen at the level of the cerebral peduncle, appears within 8 - 12 months after the ictus,Wallerian degeneration,a, b, c, d, e. MR, T2-weighted images. Hyperintensity of the left corticospinal tract extending from the internal capsule (c) to the pons (e) indicating Wallerian degeneration secondary to a focus of previous autoimmune encephalitis