不同部位脑梗死后华勒变性3例报道及文献复习

目的探讨不同部位脑梗死后锥体束华勒变性的发生过程和机制。方法报道3例不同部位脑梗死后华勒变性患者的临床资料,根据临床和影像学特点并结合文献对其进行分析。结果颈内动脉或大脑中动脉供血区急性脑梗死后可出现锥体束和胼胝体华勒变性,表现为同侧锥体束（内囊、大脑脚）与胼胝体出现T2和DWI高信号,ADC低信号,并且DWI和ADC信号改变比T2更明显;而单侧脑桥基底部梗死可于数月后出现双侧脑桥小脑束华勒变性,表现为双侧小脑中脚T2和DWI高信号,ADC等信号。结论脑梗死后华勒变性是疾病的发展过程,应充分认识这一现象,避免临床误诊为新发脑梗死。     

脑桥小脑束Wallerian变性的MRI表现

目的 分析脑桥小脑束Wallerian变性的MRI表现,以提高对该病的认识。方法 回顾性分析12例在本院行颅脑MRI检查,诊断为脑桥小脑束Wallerian变性患者的临床资料,记录原发病变的具体部位、发病时期及继发Wallerian变性的影像学特征,进一步探讨该病的发病机制。结果 自2014年1月-2017年6月于本院行颅脑MRI检查,诊断为脑桥小脑束Wallerian变性的患者共12例,原发病变均为脑桥梗死灶,其中脑梗死急性期患者1例,亚急性期患者1例,慢性期患者10例。梗死具体部位:7例位于脑桥右侧旁正中,2例位于脑桥左侧旁正中,2例位于脑桥双侧旁正中,1例位于脑桥中心。Wallerian变性均位于双侧小脑中脚,呈对称性斑片状T₂WI稍高信号,T₁WI稍低信号,其中3例患者于DWI及ADC图均呈稍高信号,1例患者于DWI呈稍高信号,ADC图呈稍低信号,其余8例呈DWI等信号。结论 脑桥正中或旁正中梗死可继发脑桥小脑束Wallerian变性,其影像学表现具有特征性,临床工作中需认识到该病。     

磁共振弥散张量成像研究脑桥梗死后神经纤维华勒变性及临床意义

目的 采用磁共振弥散张量成像(diffusion tensor imanging,DTI)动态观察脑桥梗死后,远离梗死灶的延髓及小脑中脚神经纤维华勒变性及其对患者神经功能恢复的影响.方法 选择单侧脑桥梗死患者14例,以及年龄性别相匹配的健康志愿者14名作对照组.分别在发病第1、4、12周进行DTI检测,并行美国国立卫生研究院卒中评分(National Institutes of Health stroke scale,NIHSS)、简式Fugl-Meyer运动功能评分(Fugl-Meyer motor scale,FM)、共济失调评分(ataxia rating scale,ARS)和Barthel生活指数(Barthel index,BI)评分.结果 与对照组比较,患者梗死灶同侧延髓及双侧小脑中脚的部分弥散各向异性值(fractional anisotropy,FA)从第1周至第12周逐渐减少(延髓梗死同侧FA值:第1周0.43±0.01;第4周0.37±0.02;第12周0.30±0.02,小脑中脚梗死同侧FA值:第1周0.50±0.02;第4周0.43±0.02;第12周0.35±0.04,小脑中脚梗死对侧FA值:第1周0.54±0.02;第4周0.52±0.03;第12周0.47±0.04,t=1.92～28.56,均P＜0.05),而平均弥散量(mean diffusivity,MD)的变化差异却无统计学意义(P＞0.05).在观察期间,患者梗死灶同侧延髓及双侧小脑中脚的FA值减少的百分数绝对值与同期NIHSS及BI变化的百分数绝对值呈负相关(P＜0.05).结论 局灶性脑桥梗死后,同侧延髓及双侧小脑中脚神经纤维的华勒变性持续存在,并且可能阻碍患者神经功能的恢复.     

脑型肝豆状核变性MRI诊断价值

目的：分析脑型肝豆状核变性（hepatolenticular degeneration ,HLD）的MRI特征,探讨MRI对脑型 HLD的诊断价值。方法回顾性分析经临床证实的52例脑型 HLD患者的颅脑MRI资料,所有患者均行MRI平扫及DWI成像。结果8例M RI平扫无明显异常,DWI呈等信号。38例表现为双侧基底节区及丘脑对称性分布的稍长 T1、稍长 T2信号,DWI呈稍高信号,其中11例累及中脑及脑桥,呈稍长T1稍长T2信号,4例双侧小脑齿状核呈长T2、长 T1信号影。6例表现为双侧基底节对称性短T1短T2信号,DWI呈稍低信号。36例见不同程度脑萎缩。结论 MRI对脑型HLD有很高的诊断价值,可作为影像检查首选方法,其信号变化可反映病程、判断疗效及预后。     

类固醇激素反应性慢性淋巴细胞性炎性反应伴脑桥血管周围强化症1例并文献复习

目的探讨类固醇激素反应性慢性淋巴细胞性炎性反应伴脑桥血管周围强化症(chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids,CLIPPERS)临床表现、影像学特点以及发病的可能机制。方法回顾分析1例CLIPPERS患者的临床表现、影像学特点,并结合文献进行复习。结果该例CLIPPERS患者主要临床表现为头晕、头痛、吞咽困难、口周及左侧手指麻木、视物不清、复视、四肢乏力。头颅MRI检查显示脑桥、双侧基底节区斑片状长T1长T2信号,FLARIR像呈高信号,呈小点片状强化,DWI示双侧基底节区异常信号。经糖皮质激素治疗后患者症状明显改善。复查MRI显示脑桥及双侧基底节区增强信号消失,但双侧基底节区病变仍呈长T1长T2信号。结论 CLIPPERS除典型临床和MR表现外,还可能出现双侧基底节区脑梗死,诊断时需排除中枢神经系统血管炎、淋巴瘤样肉芽肿、结缔组织病等具有类似影像学表现的疾病。该病发病机制可能由免疫和炎性反应介导所致。     

脑桥梗死后相关神经纤维继发性损害的DTI研究及其意义

目的 本研究应用弥散张量成像(diffusion tensor imaging, DTI)前瞻性观察局灶性脑桥梗死后继发神经纤维顺行性、逆行性变性的动态发展过程,探讨其对患者神经功能恢复的影响.方法 选择单侧脑桥基底部梗死患者14例,以及年龄性别相匹配的健康志愿者14名作对照组.患者分别在发病第1周、第4周和第12周进行DTI检测,对照组只做1次DTI检查.测量脑桥(患者梗死灶所在水平)及近、远端锥体束、双侧小脑中脚的MD和FA值.在每次DTI检测之前进行NIHSS、 FMS和BI评分.结果 与对照组比较,患者梗死灶及其同侧近、远端锥体束纤维、双侧小脑中脚神经纤维的FA值在各个时间点均明显减少(P<0.01);梗死灶的MD在第1周时下降,在第4周及第12周则升高(P<0.01);患者梗死灶同侧近、远端锥体束纤维以及双侧小脑中脚神经纤维的MD在各个时间点均无统计学差别(P>0.05).患者梗死灶同侧近、远端锥体束纤维以及双侧小脑中脚神经纤维的FA值,从第1周至12周随时间延长而逐渐减少(P<0.01), MD却无明显变化(P>0.05).在观察期间,梗死灶同侧近、远端锥体束纤维以及双侧小脑中脚神经纤维的FA值减少的百分数的绝对值与同期NIHSS及FMS变化的百分数的绝对值呈负相关(P<0.05),与BI无明显相关(P>0.05).结论 局灶性脑桥梗死后,可以引起与之发生联系的神经纤维发生顺行性及逆行性继发性变性,这种神经纤维的继发性变性至少在发病后12周内逐渐进展,并可能会延缓患者神经功能的恢复.     

维生素B12缺乏引起小脑病变1例及机制探讨

目的 观察1例维生素B12缺乏引起小脑病变患者的临床表现、影像学特点,探讨其发病机制.方法 收集该患者的病史及住院治疗期间体格检查、影像学检查和实验室检测资料.结果 患者维生素B12严重缺乏、巨幼红细胞性贫血.头颅核磁共振检查提示双侧小脑半球对称性大片状长T1、长T2信号,双侧放射冠、双侧基底节及脑桥腔梗灶.予大剂量维生素Bn治疗3周后复查头颅核磁共振示小脑病变基本消失.结论 维生素B12缺乏可引起小脑病变,感染可能为诱因;小脑双侧对称性病变应考虑有无维生素B12缺乏可能.     

海洛因脑病1例报告

现报告1例海洛因脑病患者的临床资料如下.1病例男,32岁.因"口齿不清、行走不稳8个月余"于2010年12月2日入院.患者吸食海洛因(纯度60％,0.1 g/d)8年,曾反复戒毒、复吸,末次吸食为8个月前.戒毒4个月后逐渐出现情绪不稳、注意集中困难、口齿不清、行走不稳.发病15 d(2010年4月26日)就诊于纽约大学医学院,MRI示双侧半卵圆中心区、尾状核尾、红核、黑质、小脑中脚、小脑齿状核及脑桥的长T1、长T2及弥散加权成像( DWI)高信号(图1);肌电图、血抗核抗体、抗双链DNA抗体、淋巴瘤病毒Ⅰ、Ⅱ、莱姆病抗体、抗Hu抗体、抗双链DNA抗体、长链脂肪酸、尿芳香硫酸酯酶A无异常;CSF总蛋白0.48 g/L,细胞学正常.诊断:运动神经元病可能性大;予以维生素C及B族治疗无效.     

橄榄脑桥小脑萎缩

多系统萎缩(MSA)是一组原因不明的散发性成年起病的进行性神经系统多部位变性疾病,主要累及锥体外系、小脑、自主神经、脑干和脊髓。临床表现可归纳为三大综合征:表现为锥体外系功能障碍的黑质-纹状体变性(SND)、表现为自主神经功能障碍的Shy-Drager综合征(SDS)和表现为共济失调的散发性橄榄脑桥小脑萎缩(OPCA)。随着病情的进展,各综合征之间的临床症状与体征可重叠组合,最后发展为多系统受损。其中,橄榄脑桥小脑萎缩以小脑性共济失调和脑干损害为主要临床表现,累及小脑、小脑中脚、脑桥基底核和延髓做榄核。导致MRI出现萎缩和信号异常的病理基础是脑桥小脑束的脱髓鞘改变,     

脑出血并发远端锥体束急性华勒变性的磁共振表现及预后分析

目的探讨脑出血并发远端锥体束急性华勒变性的磁共振表现和对患者预后的影响。方法选取基底节区脑出血患者101例,在发病第2、7、14、21天分别进行磁共振多种序列检查(T1、T2、FLAIR、DWI、ADC),了解急性华勒变性的磁共振特点。通过统计学分析,寻找脑出血并发急性华勒变性的相关危险因素。另外,通过随访明确脑出血并发远端锥体束急性华勒变性和患者预后的关系。结果完成试验患者当中,发现远端锥体束急性华勒变性患者49例(51%);发病后7 d,远端锥体束在DWI序列呈现高信号,ADC序列呈现低信号;发病后14 d,远端锥体束走形区域即可出现T2高信号改变。出血部位和出血量是脑出血后并发急性华勒变性的独立危险因素;脑出血并发远端锥体束急性华勒变性患者6个月预后不良。结论内囊出血和出血量较大患者容易并发远端锥体束急性华勒变性,DWI、ADC可于发病7 d发现该现象。同时脑出血患者出现远端锥体束急性华勒变性提示预后不良。     

Molecular mechanisms of cellular interactions in peripheral nerve regeneration

The peripheral nervous system, as opposed to the central nervous system, has the intrinsic capacity to regenerate. It was recognized long ago that this can be achieved only after an extensive clean-up procedure, the so-called Wallerian degeneration, in which myelin debris is removed and a suitable environment for growing axons is generated. Wallerian degeneration and the regeneration process itself both depend on direct cellular interactions as well as on long-range signals between all participating cell types. Elucidating the nature and functional consequences of these signals is a main goal in understanding peripheral nerve repair.     

Association between radiographic Wallerian degeneration and neuropathological changes post childhood stroke

Aim Wallerian degeneration is a radiological finding thought to reflect corticospinal tract degeneration. This finding on magnetic resonance imaging (MRI) is routinely used as a predictor of poor prognosis in childhood stroke. However, its validity has never been established. Our objective was to correlate Wallerian degeneration seen on MRI with histopathology. Method We searched the databases of the Department of Pathology and Children’s Stroke registry at the Hospital for Sick Children, Toronto for autopsy specimens exhibiting focal infarcts from children born at term who underwent MRI after a stroke. The specimens were examined for Wallerian degeneration and then correlated with the pre‐mortem MRI findings. Results Seven children (four females, three males) with a median age of 11 years (1–17y) at the time of stroke met the inclusion criteria for this study. Of the seven children included in the study with ischaemic or haemorrhagic infarcts, six had concordant Wallerian degeneration findings on both MRI and post‐mortem histopathological examination. The median time between stroke and death was 20 days (3–1825d). Interpretation Our results show for the first time that the radiographic finding of Wallerian degeneration is a valid biomarker of corticospinal tract degeneration in children who have had ischaemic or haemorrhagic stroke.     

Wallerian degeneration demonstrated by MRI and functional outcome in patients suffering from supratentorial cerebrovascular disease]

An early diagnosis of the outcome of patients with cerebrovascular disease is important for selecting the optimal treatment strategy. The purpose of this study was to estimate the prognosis of Wallerian degeneration on MRI in stroke patients with hemiparesis. The subjects consisted of 87 stroke patients, 50 hemorrhagic patients and 37 ischemic patients, who were evaluated by MRI at 1 to 6,275 days after stroke onset. Among the 36 patients who were evaluated by consecutive MRI, 161 films were obtained and analyzed. Wallerian degeneration was diagnosed when a small prolonged T 2 lesion was seen in the corticospinal tract of the brainstem on at least two contiguous slices. The atrophic rate of the midbrain was calculated as: (the area of the unaffected side of the midbrain--the area of the affected side of the midbrain)/2 x (the area of the unaffected side of the midbrain). The patients' ability to perform the activities of daily living was scored by the Barthel index (BI). Wallerian degeneration in the ipsilateral brainstem was seen for two to three months in 32 cases (37%) and in 58 films (36%) and disappeared about 3 years after the onset of stroke. Wallerian degeneration correlated with the BI scores from 2 to 6 months after stroke (p < 0.05), although no relationship was observed at 7 months or later. From 2 to 6 months after stroke, the shrinkage of the midbrain on MRI correlated with the BI scores (p < 0.001), although no relationship was observed at 7 months or later. It was therefore both Wallerian degeneration and a shrunken midbrain observed on MRIs, evaluated from 2 to 6 months after stroke were thus suggested to indicate a poor outcome in such patients.     

Bilateral wallerian degeneration of the middle cerebellar peduncles due to unilateral pontine infarction

We report the case of a patient with bilateral and symmetrical T2 hyperintensities of the middle cerebellar peduncles. She had a history of left pontine infarction 8 months before. This was attributed to bilateral Wallerian degeneration. MR Spectroscopy showed decreased N-acetyl aspartate/Creatine (NAA/Cr) ratio in the cerebellar peduncles as well as in the whole cerebellum. We hypothesize that this could reflect neuronal degeneration following a stroke.     

Quantitative and qualitative analysis of Wallerian degeneration using restricted axonal labelling in YFP-H mice

We investigated the usefulness of YFP-H transgenic mice [Neuron 28 (2000) 41] which express yellow fluorescent protein (YFP) in a restricted subset of neurons to study Wallerian degeneration in the PNS. Quantification of YFP positive axons and myelin basic protein (MBP) immunocytochemistry revealed that YFP was randomly distributed to approximately 3% of myelinated motor and sensory fibres. Axotomy-induced Wallerian degeneration appeared as fragmentation of fluorescent signals in individual YFP positive axons with a morphology and timing similar to Wallerian degeneration observed by more traditional methods. In YFP-H transgenic mice co-expressing a high dosage of WldS, a chimeric gene that protects from Wallerian degeneration [Nat Neurosci. 4 (2001) 1199], axonal fragmentation in distal tibial nerves after sciatic nerve axotomy was approximately 10 times delayed. Considerable retardations of Wallerian degeneration using the same transgenic expression system were also observed in cultures of nerve explants, enabling in vitro real-time imaging of axonal fragmentation. Remarkably, single YFP-labelled axons could be traced in peripheral nerves for unusually long distances of up to 2.9 cm exploiting confocal fluorescence imaging. Altogether transgenic YFP-H mice prove to be a valuable tool to study mechanisms of Wallerian degeneration in vivo and in vitro.     

Can diffusion tensor imaging predict the functional outcome of supra-tentorial stroke?]

We used diffusion tensor imaging (DTI) to assess wallerian degeneration of the pyramidal tract after the onset of supra-tentorial stroke, and correlation of the extent of Wallerian degeneration with the motor function at 3 months after stroke. Twenty eight patients with supra-tentorial acute stroke were examined, two weeks and one month after stroke by DTI. We measured fractional anisotropy(FA) of affected side/ unaffected side (FA ratio) in the cerebral peduncle. We used modified Rankin Scale (mRS) for assessment of motor function at 3 months after stroke. FA ratio was significantly reduced at 2 weeks after stroke (0.833 +/- 0.146) compared to on admission (0.979 +/- 0.0797). But no significant change of FA ratio was seen between two weeks and one month after stroke in 7 cases examined (0.758 +/- 0.183 vs. 0.754 +/- 0.183). In all patients in whom the FA ratio was under 0.8 at 2 weeks after stroke, motor function showed poor recovery (mRS 4 and 5) at 3 months after stroke. When FA ratio was over 0.8 at 2 weeks after stroke, motor function at 3 months after stroke showed good recovery (mRS 0 to 3) expect for three elderly patients. With the use of DTI, Wallerian degeneration could be detected in the corticospinal tracts at midbrain level during the early phase of supra-tentorial stroke. We conclude that DTI may be useful for early prediction of motor function prognosis in patients with supra-tentorial acute stroke.     

脑缺血大鼠锥体束Wallerian变性的病理学验证

目前对Wallerian变性的研究主要以神经影像学为主,很难发现脑损伤后早期的Wallerian变性现象。实验旨在从病理学角度发现脑损伤后Wallerian变性的更早、更明确的证据。电镜观察发现,脑缺血3周大脑脚出现脱髓鞘迹象,6周时大脑脚和颈膨大均有明显脱髓鞘表现。生物素葡聚糖胺锥体束顺行示踪结果显示,神经功能损伤越严重,内囊、大脑脚和颈膨大锥体束显示越差,Wallerian变性越严重。     

Time course of wallerian degeneration after ischaemic stroke revealed by diffusion tensor imaging

Wallerian degeneration (WD) after ischaemic stroke is a well known phenomenon following a stereotypical time course. Whereas conventional magnetic resonance imaging fails to detect signal intensity changes until four weeks after stroke, diffusion tensor imaging (DTI) reveals changes related to WD only after days. DTI was used to monitor the time course of Wallerian degeneration of the pyramidal tract from the early subacute to the late chronic stage of ischaemic stroke in two patients. A progressive decrease of fractional anisotropy was found along the pyramidal tract in the cerebral peduncle below the primary lesion resulting from progressive changes in the principal diffusivities, as well as a slight increase in the orientationally averaged diffusivity in the chronic phase. These signal changes reflect the progressive disintegration of fibre structures resulting from WD.     

The effects of claudin 14 during early Wallerian degeneration after sciatic nerve injury

Claudin 14 has been shown to promote nerve repair and regeneration in the early stages of Wallerian degeneration(0–4 days) in rats with sciatic nerve injury, but the mechanism underlying this process remains poorly understood. This study reported the effects of claudin 14 on nerve degeneration and regeneration during early Wallerian degeneration. Claudin 14 expression was up-regulated in sciatic nerve 4 days after Wallerian degeneration. The altered expression of claudin 14 in Schwann cells resulted in expression changes of cytokines in vitro. Expression of claudin 14 affected c-Jun, but not Akt and ERK1/2 pathways. Further studies revealed that enhanced expression of claudin 14 could promote Schwann cell proliferation and migration. Silencing of claudin 14 expression resulted in Schwann cell apoptosis and reduction in Schwann cell proliferation. Our data revealed the role of claudin 14 in early Wallerian degeneration, which may provide new insights into the molecular mechanisms of Wallerian degeneration.