医学精品课件：脑感染(八年制)-cww-v1.ppt

1、 Radiology of CNS Infection华中科技大学同济医学院华中科技大学同济医学院同济医院放射科同济医院放射科陈唯唯1.Intracranial infections include abscess,meningitis and encephalitis.2.Infections can be caused by pyogenic,tuberculous,viral or parasitic organisms.3.They may lie within brain parenchyma,the subdural or epidural spaces or may involv

2、e compartment.4.CT and MRI play important roles in the early diagnosis of infections.Haemophilus Influenzae type B(Hib)Meningococcus Pneumococcus Etiological agents?-leading causes(2/3)No.1No.2No.3(Epidemic cerebrospinal meningitis)Clinical findings of meningitis Signs and symptomsuFeveruHeadacheuAl

3、tered mental status-lethargy to comauNeck stiffnessuIncreased intracranial pressure-nausea/vomiting,bulging fontanelle in infants,papilledema 视乳头水肿uMeningeal irritation-Nuchal rigidity and Brudzinskis and Kernigs signs(+)Frequently hematogenous spread CT/MRI No abnormal findings Hydrocephalus+C:prom

4、inent meningeal enhancement Complications:ventriculitis(ependymitis),subdural empyema,infarction meningeal enhancement&subdural effusion(enhanced CT)MRI:meningeal enhancement (dura/cerebellar tentorium/cerebral falx)subdural effusion cerebritis Ependymitis&subdural empyemauThe imaging appearances de

5、pend on the maturity of the abscess at the time of scanning.uInitially there is a cerebritis,later the abscess increases in size,becomes rounded and a central necrosis develops with a thick wall.uThe abscess shows ring-like enhancement(光滑环形强化光滑环形强化)on both CT/MRI.Usually smooth ring.Nodular or solid

6、 enhancement,incomplete thin rings,or thick and irregular rings may be observed.uDaughter abscesses(子脓肿)appear as contiguous enhancing small rings.l病理：局灶性或多灶性炎性改变，有水肿，灶性坏死和斑点状出血.lCT：低密度占位病变，斑片/脑回 样强化.lMR：边界不清的长T1长T2信号病变有占位效应，常有斑状/脑回强化.l脑组织坏死，周边有肉芽组织形成lCT/MR：边界不清的环形增强占位病变,水肿及占位效应均明显.l囊腔内为坏死组织，脓或干酪 物质

7、，囊壁为胶原样物质lCT/MR：边界清楚的薄壁环形 强化病变 l 可存在数周至数年l 胶原包膜增厚l 壁变厚，环皱缩，水肿及占位减轻 contiguous enhancing small rings.Cerebral abscess DWI:High SIDiffusion weighted imaging（扩散加权成像,DWI）lHSV-1型感染l病理呈出血坏死性脑膜脑炎l边缘系统受累边缘系统受累（颞叶,额下区,扣带回）l急性起病lCT：早期正常 颞叶低密度病变，20-50%双侧 斑状/脑回强化 后期局灶性出血lMRI：较CT敏感 边缘系统长T1长T2信号 局灶出血，各种不同强化 双侧较特异

8、uSpread of the mycobacterium to CNS is hematogenous from a pulmonary source.uThree types Meningitis Tuberculoma:2-6 cm Military cerebral TB:multiple,small Imaging FeaturesuTuberculous meningitis:thick,gelatinous exudates in the basal cisterns;meningeal thickening and prominent enhancementugranulomas

9、:node or ring enhancement,T2WI:low SI,multiple small or large nodules.uVasculitis infarctionuhydrocephalusl结核性脑膜脑炎 颅底池明显 可影响脑池脑沟内CSF循环，引起脑积水l结核瘤 脑膜，脑实质，有特征性（短T2）l结核性脑脉管炎 血管狭窄，引起脑缺血，脑梗塞Tuberculous meningitisTuberculous meningitisDiffuse intense enhancement in the suprasellar cistern,sylvian C&perimes

10、encephalic C.Hydrocephalus.Infarction in right hemisphereTuberculous meningitisTuberculous meningitis&TuberculomaTuberculous meningitis&TuberculomaTuberculoma TB meningitis infarction in basal ganglia and internal capsulaCord TB and Syrinxl脑囊虫病l脑血吸虫病l脑肺吸虫病l裂头蚴病l阿米巴l疟疾l弓形体cysticercosisl蚴虫及死亡后释放的异体蛋白引

11、起炎症反应l脑实质脑室蛛网膜下腔，囊泡510mm.l影像 囊泡期（活蚴虫）：囊及头节，无水肿 胶样囊泡（死蚴）：环形强化，有水肿 肉芽结节（已治愈）：皱缩环，钙化头节 钙化结节（残余）：小钙化结节，不强化cysticercosiscysticercosiscysticercosis脑血吸虫病(schistosomiasis)u占2-4%，20-50岁多见u传播至脑的途径：虫卵栓子动脉系统脑 肺动、静脉瘘Batons V丛脑 蠕虫异位移行脑u部位：大脑、小脑、脑干、软脑膜及脉络丛、脑室内病理表现：急性期：虫卵分泌毒素和代谢产物 急性炎症虫卵周围大 量嗜酸细胞嗜酸脓肿 分布于皮质及皮髓交界处，边界

12、不清的团块。慢性期：大量虫卵沉积和异物反应 肉芽肿，虫卵死亡，纤 维结节脑萎缩和瘢痕形 成，虫卵栓塞血管或脉管 炎脑卒中 平扫：急性期长T1、长T2信号 慢性期肉芽肿 T1WI：等，稍低 T2WI：高，稍高灶周水肿增强：斑点及小斑片强化 多个结节强化 MRI 特点Tongji Hospital1.The disease has been associated with viral illness,vasculitides,vaccination and MS2.The cord swelling and slight expansion,extending over several verte

13、bral body segments3.hypointensity on T1WI and hyperintensity on T2WI4.Enhancement is moderate to marked following contrast administration5.In the later course of the disease,the cord appear normal,but more often atrophic颈段脊髓炎Acute Myelitisu常见的脱髓鞘病变,与自身免疫反应或病毒感染有关.u缓解与复发反复进行.u20 40 Y 多发.uF：M=1.7:1 5-

14、10:1u常累及脑实质，脊髓和视神经u早期:髓鞘崩解和细胞增生.小胶质细胞增生,吞噬类脂质后形成泡沫细胞.淋巴细胞、浆细胞和巨噬细胞沿充血的小血管周围浸润，形成所谓血管周围袖套。病灶常以小静脉为中心。疾病发展时，病灶扩大融合。u疾病稳定或好转时，即慢性期或不活动期，细胞浸润消退，髓鞘脱失仍然存在，并有星形细胞和胶质增生，少突胶质细胞减少，轴索相对保存。uCT：病灶较大时为低密度区，圆形/椭圆形uMRI:脑白质的多发性病灶,T1WI等低信号,T2WI高或较高信号,长条形或椭圆形,病灶长轴与脑室长轴相垂直-直角征;“病灶中的病灶”“靶状”：病灶双重信号 脑干、小脑、视神经、脊髓受累；脑萎缩.u +C:急性期/新鲜病灶常出现强化,实质性或 环状强化.激素治疗后强化减少或消失.M S caseM S caseM S caseM S case 2M S case 2MS-Case 3MS with optic neuritisM S“Subcortical U fibres”Juxta-cortical lesionsJuxta-cortical lesionsJuxta-cortical lesionsTongji HospitalMSuPyogenicuTuberculousuViral uParasitic organismsuMyelitisuMutiple sclerosis