脑白质病变ppt课件

脑白质病变 Cerebral White Matter Disease,1,脑白质病变定义,脑白质病变病因,血管源性白质病变,白质病变与认知损害,2,脑白质病变临床常见，多种疾病累及神经系统白质,分原发、继发性两大类.,病理过程：髓鞘形成延迟、髓鞘形成障碍、脱髓鞘,诊断：临床+MRI+病理,脑白质病变,Ann N Y Acad Sci. Oct 2008; 1142: 266309.,3,Genetic,2,Demyelinative,3,Infectious,4,Inflammatory,5,Toxic,Etiology of CWM Disorders,6,1,7,8,9,10,11,Metabolic,Vascular,Traumatic,Neoplastic,Hydrocephalic,Degenerative,4,5,MRI of X-ALD,MLD,GLD,VWMD,(A) X-连锁的肾上腺脑白质营养不良(X-ALD), T1 image;(B)异染性脑白质营养不良(MLD), FLAIR image; (C)球形细胞脑白质营养不良(GLD), T2-weighted image; (D)白质消融性脑白质病(VWMD), T1-weighted image.X-ALD:impaired psychomotor speed, spatial cognition, memory, and executive functions; MLD:psychosis, behavioral disturbances, and dementia; GLD: hemiparesis, intellectual impairment, cerebellar ataxia, and visual failure;,Ann N Y Acad Sci. Oct 2008; 1142: 266309.,6,神经轴索球样细胞脑白质营养不良,(A) FLAIR MRI in the axial plane showing confluent high signal in the periventricular, deep, and subcortical white matter of the frontal and parietal lobes extending through the splenium of the corpus callosum. (B) Gross pathology of a coronal section of the cerebral hemisphere, showing gliosis in the centrum semiovale (arrow) and internal capsule (arrowhead). The disorder usually presents with executive system dysfunction and other neurobehavioral deficits, progressing to dementia.,7,MRI in patients with MELAS,Criteria for diagnosis are stroke like episodes before age 40 (not confined to vascular territories); encephalopathy characterized by seizures, dementia, or both; with lactic acidosis and/or ragged-red fibers. Recurrent headache or vomiting may be present. Periventricular and diffuse WM hyperintensities, as well as areas of cortical infarction and cerebral edema, are seen on MRI,8,脆性X相关震颤和(或)共济失调综合征,White matter pallor is seen in the cerebellar parenchyma (A), as well as in the middle cerebellar peduncles (B).Progressive cognitive decline is characterized by impaired executive function, working memory, intelligence, declarative learning and memory, information processing speed, temporal sequencing, and visuospatial functioning, but language is spared.,9,10,FLAIR MRI in multiple sclerosis,(A) White matter hyperintensity perpendicular to the lateral ventricle (Dawsons finger), shown by the arrow. (B) In a second case, the focal area of hyperintensity (arrow) corresponded to the initial clinical presentationCognitive impairments in MS also include a wide range of focal neurobehavioral syndromes and neuropsychiatric disturbances,11,MRI features of ADEM,(A) Coronal T1-weighted postgadolinium image showing enhancing lesions in the right more than left hemispheres. (B) Axial zero-B MRI demonstration of the multiple lesions. (C) FLAIR MRI 6 months after marked clinical recovery shows much improved areas of hyperintensity.,12,13,HIV,FLAIR MRI showing hyperintensities in prefrontal white matter in a patient with HIV and cognitive impairment,Schmahmann JD, Pandya DN. Fiber Pathways of the Brain. Oxford University Press; New York: 2006,14,PML,(A) T2-WI shows involvement of white matter of the right occipital region (arrow), accounting for the hemianopsia in this HIV-positive patient. (B) FLAIR MRI in a patient with systemic lymphoma and PML, demonstrating confluent prefrontal white matter lesion spreading across the genu of the corpus callosum (arrow), and additional lesions affecting local association fibers of the right prefrontal and parieto-occipital cortices (arrowheads). (C, D) Axial FLAIR images in an HIV-positive patient showing confluent subcortical and deep white matter involvement by PML.,Cognitive presentations include frontal lobe syndromes and aphasia, progressing to quadriparesis, mutism, and unresponsiveness,15,16,17,Toxic Leukoencephalopathy,FLAIR MRI in the axial plane of a patient with cognitive decline after receiving methotrexate,T2-W MRI appearance in the axial plane of toluene encephalopathy in two patients a dramatic syndrome of dementia, ataxia, and other neurologic signs,18,Heroin,Clinical manifestations include cerebellar motor findings of ataxia, dysmetria and dysarthria, bradykinesia, rigidity, and hypophonia, and the syndrome may progress over weeks to pseudobulbar palsy, akinetic mutism, decorticate posturing, and spastic quadriparesis.,MRI scans after heroin inhalation, known colloquially as “chasing the dragon.” FLAIR images in the axial plane (AD). Inhalation of heated heroin vapor (colloquially termed “chasing the dragon”) produces a devastating, progressive spongiform leukoencephalopathy.,19,20,Hypoxic ischemic encephalopathy,Axial MRI in delayed leukoencephalopathy after hypoxicischemic insult. (A) FLAIR image shows extensive, symmetric white matter hyperintensities with relative sparing of subcortical white matter. (B) Diffusion-weighted imaging shows restricted diffusion of the white matter abnormalities, confirmed on (C), apparent diffusion coefficient mapping,21,22,23,Gliomatosis cerebri,FIG 3. 55M.A, Axial T2-weighted spin-echo localizer image (1900/80).B, Corresponding spectrum. Stereotactic biopsy sample was taken from the denoted voxel, with a maximum Cho/NAA ratio of the lesion of 8.9 as well as a lactate doublet at 1.35 ppm. FIG 4. 10 year old boy with seizure.,24,朗格汉斯细胞组织细胞增多症,T2-weighted axial MRI in a patient with Langerhans cell histiocytosis, showing hyperintense signal abnormality in the white matter of the cerebellum,25,26,B,C,A,WM lesions,Aging,脑白质病变,Vascular Disease,27,白质高信号（WM Hyperintensities ）,Leukoaraiosis is visible as (A) white matter hypodensity on CT and (B) white matter hyperintensity on FLAIR MRI in the same patient.,28,02,03,04,01,70岁以上老人 ，95% 在MRI上可以发现白质高信号 ，随年龄增加逐渐增多,危险因素：高血压、糖尿病、吸烟,、视网膜血管改变、肾脏血管改变；,内皮功能紊乱 (血清同型半胱氨酸和细胞粘附分子1), 血栓形成 (血栓调节蛋白和 纤维蛋白原）, 炎性反应 (CRP), 氧化应激2,髓鞘脱失和胶质增生，破坏髓鞘和少突胶质细胞影像学发现和病理学显示的髓鞘脱失具有相关性,WMH的相关概念,1.J Neurol Neurosurg Psychiatry. 2001 Jan; 70(1):9-14.2.Brain. 2004 Jan; 127(Pt 1):212-93.Neurology. 2006 Sep 12; 67(5):830-3.,29,01,WMH 负荷 与脑梗死以及卒中史相关,02,与脑血管病有共同的危险因素，如高血压等,03,利用 ACEI 和利尿剂降压治疗可以减缓 WMH 进展,04,CSVD 导致血管狭窄、阻塞, 破坏血管的反应性，导致白质低灌注,05,认知障碍病人WMH高负荷，局部脑血流量下降代谢水平降低,WMH的病理机制,30,脑白质病变与认知功能下降显著相关,脑白质病变越严重，认知功能下降越快,Stroke 2005;36;56-61.,脑白质恶化级别,无,1级,2级及以上,初次MRI,随后的MRI,年,改良后的MMSE评分,9594939291908988878685,4 5 6 7 8 9 10 11,31,高的WMH 负荷与认知功能从正常转化到MCI，MCI转化到痴呆有关系,脑室周围的 WMH 与将来的痴呆特别是AD相关,在MRI上见到的白质高信号（WMH）同正电子发射断层扫描（PET）中使用的脑淀粉样标记物一样，可以独立预测AD诊断,WMH 与认知改变,32,WMHs 影响信息加工速度和执行功能 ，影响记忆的提取而不是编码,1,脑室周围白质区域为“远端供血区”，这种情况因为缺乏吻合更易受到中度血流降低的损害,2,脑室周围 WMHs破坏联系较远皮质区域的联系性长束，执行功能受累较为突出,3,皮质下区域由致密的短回路U纤维组成，皮质下痴呆则主要是认知过程速度减慢,4,WMHs相关的认知改变,33,Otto Binswanger在1894年首先提出WMCs与痴呆之间可能存在关联；Alzheimer在1902年再次提到Binswanger的病例，以后提出Binswanger脑病（BD）这一名词。,1,WMC是痴呆的危险因素，与认知功能下降有关。头部CT检出的AD患者WMCs可占30%，VaD患者可占70%。 WMC与 AD 密切相关，提示血管病因素在AD病变过程中的重要性。,2,皮质下白质缺血主要是少突胶质细胞和髓鞘破坏； 皮质下U纤维的密度较高WMLs主要破坏由弓状U纤维组成的短的皮质-皮质联系；脑室周围WMLs则破坏联系较远皮质区域的联系性长束,3,脑白质改变（WMC）与 AD,34,1,2,3,4,主要累及脑皮质小动脉、中动脉、微动脉及毛细血管，表现为血管壁A的进行性沉积,5,是老年人自发性颅内出血和认知损害的重要原因,临床表现主要包括：反复颅内出血，认知下降和痴呆等,约30%的脑血管淀粉样变性患者可以出现老年痴呆症状，如严重的记忆障碍、注意力、定向力和计算力减退，或精神异常,型的主要病理改变是皮质微血管内A的异常蓄积；型的A主要沉积于脑膜血管及皮质动脉、小动脉，偶尔会累及静脉。,脑淀粉样血管病 (CAA),35,CAA的MRI 表现,(A) Gradient echo MRI demonstrating multiple punctuate areas of hemorrhage (microbleeds, arrow) at the corticosubcortical junctions. (B) MRI FLAIR sequence in a patient with lobar intraparenchymal hemorrhage in the left occipital lobe (double arrows), as well as periventricular WMH (single arrow) and subcortical WMH (arrowheads),36,1894年Binswanger首先报道该病例，并强调本病患者的两个主要特点：（1）患者的脑血管有重度粥样硬化。（2）大脑半球白质损害明显，而皮质几乎不受影响,01,深穿支动脉供血的脑室周围白质发生大面积缺血性损害，仅有皮质穿支动脉供血的皮层下U型纤维未见明显受损,02,痴呆是最显著的症状，主要表现为记忆障碍、计算力差，可伴有心情、人格的改变，无欲、淡漠、精神错乱,03,Binswangers 脑病,37,Binswangers MRI,Hyperintense signal abnormality is seen at periventricular zones, white matter immediately beneath cortex, splenium of the CC, and internal and external/extreme capsule regions. Multiple hypodensities consistent with lacunar infarcts are also seen in the basal ganglia and thalamus,Schmahmann JD Fiber Pathways of the Brain. Oxford University Press; New York: 2006,38,CADASIL,39,CADASIL MRI,(A, B) FLAIR MRI in an asymptomatic 39-year-old, notch 3 gene positive with family history of early stroke, whose imaging findings were incidentally noted. Characteristic temporal lobe white matter involvement is highlighted (arrows). (C) FLAIR MRI in a patient with clinically established CADASIL. (D) T2-weighted MRI in a patient with notch 3 gene and pathologically proven disease.,40,神经行为综合征,神经精神综合征,白质性痴呆,脑白质病变与神经精神综合征,41,A,B,C,局部的白质病变导致失语,失用症(apraxia),失认症(agnosia),胼胝体分离综合征(callosal disconnection)等,主要病因是卒中，肿瘤和脱髓鞘病也可以发生,病变部位：顶下小叶、颞顶交界、前额叶、基底节、丘脑、扣带回等，以非优势半球多见,Neurobehavioral Syndromes,42,Focal WM lesions with neurobehavioral manifestations,(A) Lacune in the genu of the right internal capsule (arrow) on CT presenting with hemineglect. (B) Diagram of the WM lesion responsible for parietal pseudothalamic pain syndrome, thought to disrupt the second somatosensory cortex from thalamus. (C) FLAIR MRI of posterior reversible encephalopathy syndrome producing visual loss. (D, E) Focal WM lesion consisting of metastatic melanoma with surrounding edema, producing alexia without agraphia.,43,03,神经精神综合征是一组与神经系统疾病相关的行为和精神症状，可以分为情感障碍和精神行为障碍两类,02,白质病变对情感情绪、精神行为等非认知功能等产生影响，从而导致精神行为异常。,01,精神行为障碍指的是大脑机能活动紊乱，导致认知、情感、行为和意志等精神活动不同程度障碍的总称，包括幻觉、妄想、异常行为等,情感障碍以心境或情感异常改变为注意临床特征，包括抑郁、焦虑、情感淡漠、躁狂等；,04,神经精神综合征,44,请在此处输入您的文本，或者将您的文本粘贴到此处。,1,白质性痴呆,请在此处输入您的文本，或者将您的文本粘贴到此处。,1,请在此处输入您的文本，或者将您的文本粘贴到此处。,1,请在此处输入您的文本，或者将您的文本粘贴到此处。,1,请在此处输入您的文本，或者将您的文本粘贴到此处。,5,请在此处输入您的文本，或者将您的文本粘贴到此处。,1,请在此处输入您的文本，或者将您的文本粘贴到此处。,1,请在此处输入您的文本，或者将您的文本粘贴到此处。,2,请在此处输入您的文本，或者将您的文本粘贴到此处。,3,可能机制：白质主要起连接作用，将皮层、皮层下灰质连接起来，构成完整的功能体系，白质病变导致联络中断,4,请在此处输入您的文本，或者将您的文本粘贴到此处。,请在此处输入您的文本，或者将您的文本粘贴到此处。,弥漫性损害可以表现为：记忆力下降、注意力障碍、思维迟缓、情感和人格改变，视空间和执行功能异常等,请在此处输入您的文本，或者将您的文本粘贴到此处。,请在此处输入您的文本，或者将您的文本粘贴到此处。,白质性痴呆概念于1988年提出，特指由于白质病变导致认知功能下降达到了痴呆的程度的临床综合征,请在此处输入您的文本，或者将您的文本粘贴到此处。,特定部位白质损害使神经联络中断产生各种症状，如遗忘、传导性失语、失读、失写、失用、视觉失认、意志缺乏、缄默等,皮层性痴呆以记忆编码和语言障碍为特点，皮层下痴呆以锥体外系功能和程序记忆障碍的主要特点,45,WM dementia,FLAIR MRI in the axial plane of an 80-year-old man with slowly evolving WM dementia. No single cause has been identified for the cognitive decline or WM hyperintensities,46,Summary,多种疾病累及中枢神经系统的脑白质，脑白质病灶又分为原发和继发性两类。脑白质病按发病时髓鞘是否发育成熟进一步分为先天性和遗传性脑白质病、获得性脑白质病,白质主要由神经纤维、轴突和胶质细胞组成，不含神经元胞体或突触。皮质下结构的白质可分为皮质下区域和脑室周围区域。皮质下白质缺血主要是少突胶质细胞和髓鞘破坏。,1,2,脑白质变化与认知功能下降密切相关，脑小动脉病变是白质病变的主要原因；年龄、高血压是重要危险因素；白质改变能促进或加重AD患者认知功能障碍,3,47,48,