Chiari—Ⅰ型畸形的CT诊断

本文报告了21例Chiari—Ⅰ型畸形,均经CT确诊,其中9例行CTM检查,同时与20例MR确诊的Chiari—Ⅰ型畸形及60例颅底凹陷症进行比较分析。Chiari-Ⅰ型畸形的CT表现为:轴位扫描图像示椎管内颈髓后方软组织密度肿块影,与上方后颅凹内小脑扁桃体相延续,颈髓受压、变形。矢状重建图像示小脑扁桃体向下延伸入椎管内,小脑延髓池变窄或消失。笔者认为:脑干屈曲是颅底凹陷症的一种病理改变,而非Chiari-Ⅰ型畸形的伴随表现。     

ChiariⅠ型畸形的诊断标准再探讨

目的采用新方法再探讨ChiariⅠ型畸形的诊断标准。方法利用医用计算机图像处理软件0SIRIS,对27例小脑扁桃体下疝超过5mm的ChiariⅠ型畸形病例、25例小脑扁桃体下疝<3mm的可疑ChiariⅠ型畸形病例以及40例不伴中枢神经系统疾病的患者的头颅MRI图像分别进行颅腔和脑实质的径线与面积的测量,并对测量结果作统计学分析。所选病人均在18岁以上,MRI资料完整,不伴颅内高压、环枕融合和颅底凹陷。结果ChiariⅠ型畸形可疑组的枕底长与斜坡长的比值明显大于ChiariⅠ型畸形组(P<0.05),后脑面积与后颅窝面积的比值明显小于ChiariⅠ型畸形组(P<0.05),而这2项测量结果与对照组之间差异无显著性(P>0.05);此外,可疑组的后脑面积与大脑面积及大脑面积与幕上颅腔面积的比值与对照组和ChiariⅠ型畸形组间差异均无显著性(P>0.05)。结论ChiariⅠ型畸形以小脑扁桃体下疝超过5mm为诊断标准较为合理,下疝<3mm应视为正常。该研究结果也支持后颅窝骨发育不良导致后颅窝过度拥挤是ChiariⅠ型畸形发病机制的学说。     

同卵双生Chiari I型畸形2例报告

同卵双生兄弟共患Chiari Ⅰ型畸形文献报告不多,我们遇2例报告如下:例1,兄年35岁,于1990年因头痛逐渐加重、口角歪斜就诊。经CT和MRI确诊为脑积水、小脑扁桃体下疝,脊髓空洞症(图1)。例2,其弟40岁,于1995—03入院。3年前开始双下肢无力、僵硬逐渐加重,走路不稳,常向前、向左倾斜或摔倒,右腿伴不自主抽动。经常左季肋部疼痛,入院前几日疼痛加重。经头部CT诊断为脑积     

阿-希二氏畸形合并脊髓空洞症的MRI研究

目的:利用MRI技术,研究Chiari Ⅰ畸形合并脊髓空洞症的影像学特征。材料与方法:回顾性分析经MRI证实的Chiari Ⅰ畸形55例,其中7例经手术治疗。用Siemens 1.0T MR扫描仪,对脊髓和后颅凹进行矢状和横断面扫描,选择SE T_1WI和T_2WI成像序列。结果:55例Chiari Ⅰ畸形患者中,小脑扁桃体下疝长度为6～25mm,平均9mm。合并脊髓空洞症42例(76％),其中30例(71％)有脊髓增粗,这多发生在无间隔的空洞中。呈“串珠样”改变者,脊髓径正常或变细。小脑扁桃体下疝的长度与脊髓增粗和脑室扩大无相关性。经手术治疗的7例中,5例扁桃体下疝消失,2例症状改善。1例复发。结论:MRI技术可以对Chiari Ⅰ畸形和脊髓空洞症患者提供术前影像学诊断,并可进行术后追踪观察。     

Chiari畸形Ⅰ型的MRI诊断价值

Chiari畸形是一种以小脑扁桃体下疝为特点的先天性疾病，Chiari畸形主要分为3型，其中以Ⅰ型最多见，其主要病理特点是小脑扁桃体与小脑下部向下移位疝入到椎管内，但延髓与四脑室位置正常，     

Joubert综合征1例

患者女,1岁6个月,发育迟缓, 认知缺陷,共济失调,眼球震颤、斜视,肌张力减低、巴彬斯基征阳性,呼吸失调,曾因Ⅰ型呼吸衰竭住院治疗. CT及MRI平扫:中脑增宽,两侧小脑上脚增宽且近于平行走向,脚间池加深,两侧小脑上脚与中脑呈磨牙样改变;小脑蚓部缺如,双侧小脑半球不连,中间见线状裂隙和四脑室相延续,四脑室形态不规则,上部层面呈蝙蝠翼状,下部层面呈三角形,矢状面小脑上脚与脑干垂直.     

胎儿胼胝体发育异常的产前MRI表现

目的分析胎儿胼胝体发育异常的产前MRI表现。方法对20例孕妇进行MR检查,年龄24~37岁,平均28.7岁;孕龄20~34周,平均29.3周。利用GE 1.5T MRI对胎儿颅脑进行横轴位、冠状位及正中矢状位SSFP、TSE、TFET1WI及DWI序列,扫描得到符合诊断的MRI图像,由2名影像科高级职称医师分开进行图像分析而得出结论。结果20例患者中单纯完全性胼胝体缺如14例、部分型缺如6例,伴发畸形有脑积水1例、Dandy--walker变异型畸形2例、伴大脑镰旁囊肿1例、后颅窝池增宽2例。结论 MRI能及早准确诊断胼胝体畸形及并发脑发育畸形,对于优生优育起到很好筛查和帮助。     

小儿先天性脑发育异常的CT表现

目的分析先天性脑发育异常的CT表现。方法38例临床上疑有脑发育异常的患儿(男29例，女9例，年龄2个月～9岁)均经cT检查。结果38例患儿中，胼胝体发育不良见于i例，积水型无脑畸形5例，灰白质发育异常12例(其中伴脑裂畸形4例)，蛛网膜囊肿6例，其他病变6例。结论cT是诊断先天性脑发育异常的首选方法，且对指导计划生育工作有重要意义。     

小脑发育不良性神经节细胞瘤3例的磁共振成像表现

目的分析小脑发育不良性神经节细胞瘤的影像学特征,提高对该病术前诊断的准确性。方法回顾性分析3例经手术病理证实的小脑发育不良性神经节细胞瘤的CT和磁共振成像(MRI)表现,并结合文献复习总结其影像学特征。结果 3例均为女性,发生在左侧小脑半球2例,发生在右侧小脑半球和四叠体池区1例,MRI表现为长T1WI、长T2WI信号,其内见条纹状等T1WI、等T2WI信号,增强扫描无强化;其中2例伴发脑积水,1例合并瘤内出血。结论小脑发育不良性神经节细胞瘤具有一定的影像学特征,典型表现者术前可作出定性诊断。     

中暑引起小脑综合征——临床表现和CT所见

作者报告1例中暑及恢复后小脑综合征的临床和CT所见。病人女,50岁,高温中暑后因有明显的共济失调而入神经科。神经系统检查有典型小功脑能障碍。中暑第7天,脑CT扫描正常。5个月后复查CT发现两侧小脑半球和蚓部区域萎缩.小脑上池和桥小脑角池增大,小脑延髓池和第4脑室增宽。大脑半球和脑干未见异常变化。作者指出,小脑综合征是中暑最常见的持久性神经系统的后遗症。中     

CT findings in spinocerebellar degeneration

Thirty-five CT scans were studied from patients with several forms of spinocerebellar degeneration. Atrophy was determined by objective measurements of the number and width of cerebellar sulci, transverse diameter and surface area of the fourth ventricle, brainstem ratio, cerebellopontine angle cistern, and Evans' index. Two-thirds of the patients with Friedreich's ataxia showed moderate cerebellar atrophy and an increase in the surface area of the fourth ventricle. Severe cerebellar atrophy and enlargement of the cerebellopontine angle cistern was seen in patients with olivopontocerebellar (OPC) atrophy and idiopathic cortical cerebellar atrophy. In the OPC atrophy group there was also prominent atrophy of the brainstem and an increase in the fourth ventricle parameters. Alcoholic cerebellar degeneration showed a specific pattern of cerebellar atrophy most prominent in the superior vermis, together with a slight increase in the fourth ventricle surface, a reduction in the size of the brainstem, and an enlargement of the cerebellopontine angle cistern. Supratentorial atrophy was present only in the OPC and alcoholic atrophy groups. In one patient with spastic ataxia, CT was normal but MR imaging revealed prominent atrophy of the spinal cord. These CT patterns appear to be distinctive enough to permit the diagnosis and classification of the various forms of spinocerebellar degeneration.     

Cerebellar vermian atrophy after neonatal hypoxic-ischemic encephalopathy

BACKGROUND AND PURPOSE: Although pathologic evidence of cerebellar injury due to birth asphyxia is well described, neuroimaging evidence is sparse. The primary purpose of this retrospective study was to evaluate the early and late imaging findings in the cerebellum of patients who had neonatal hypoxic-ischemic encephalopathy with thalamic edema shown by neonatal CT. The secondary aims were to validate thalamic edema shown by neonatal CT as a marker of thalamic injury and to assess the late cerebral cortical abnormalities associated with neonatal thalamic edema. METHODS: Fifty-five neonates with thalamic edema shown by CT performed when patients were 3 days old were identified from a cohort of full-term neonates with hypoxic-ischemic encephalopathy. Twenty-six of the 55 underwent follow-up neuroimaging. All sonograms, CT scans, and MR images of the brains of the 55 neonates were retrospectively reviewed by two pediatric neuroradiologists. The examinations were reviewed for evidence of hemorrhage, edema, atrophy, and CT attenuation or MR signal intensity abnormalities in the cerebellum, basal ganglia, and cerebral cortex. The neonatal autopsy findings in four cases were reviewed separately by a pediatric neuropathologist. RESULTS: Of the 55 neonates with thalamic edema shown by neonatal CT, 28 (51%) had thalamic edema with diffuse cerebral cortical edema, and 27 (49%) had thalamic edema without diffuse cortical edema. The cerebellar vermes appeared normal on all neonatal sonograms, CT scans, and MR images. However, atrophy of the cerebellar vermis was found in 12 (46%) of 26 patients by use of follow-up studies (95% CI, 27-65%). One of the 12 patients also had cerebellar hemispheric atrophy. Cerebellar vermian atrophy was shown at follow-up in eight (67%) of 12 patients who had neonatal thalamic edema with cortical sparing, compared with four (29%) of 14 patients who had thalamic edema with diffuse cortical edema. The difference did not reach statistical significance. The thalami appeared abnormal on follow-up neuroimages in 25 of 26 cases. Different patterns of cortical atrophy were observed on the images of patients who had thalamic edema with cortical sparing compared with those obtained in patients who had thalamic edema with cortical involvement. CONCLUSION: Cerebellar vermian atrophy is a frequent finding on follow-up images of patients in whom neonatal CT showed hypoxic-ischemic encephalopathy with abnormal thalami.     

Brain atrophy in 18 patients with Down syndrome: a CT study

Individuals with Down syndrome develop neuropathologic and in some cases clinical evidence of Alzheimer disease after age 40. We compared CT scans of 18 Down syndrome subjects, 26-70 years old (seven of whom satisfied criteria for dementia), with 175 screened normal volunteer control subjects for evidence of cortical and subcortical atrophy. CT scans were analyzed as a function of age and cognitive status. The suprasellar cistern ratio, presumed to measure mesial temporal-lobe atrophy (or hypoplasia), was correlated with severity of cognitive impairment, even when age effects were removed. The suprasellar cistern ratio predicted dementia status with an accuracy of greater than 75%. Brain measurements on CT scans showed a distinct pattern of increased abnormality with age in patients with Down syndrome; this differed clearly from that seen in controls.     

小脑幕切迹下疝的CT诊断

目的 确定小脑幕切迹下疝的CT表现。方法 回顾性分析经临床证实的68例小脑幕切迹下疝的CT表现。结果 CT显示因脑组织移位及中脑本身受压移位导致单侧或双侧鞍上池改变60例、脚间池改变56例、环池改变52例、四叠体池改变50例。多数为前疝和半环疝。均有脑干的移位、旋转及变形改变，可伴有四脑室的变窄、闭塞及幕上占位病变的一系列改变。结论 参考原发病变的占位程度，脑干与脑干周围脑池两CT改变均存在并结合起来分析，可作出正确诊断。     

Infantile-onset spinocerebellar ataxia: MR and CT findings.

PURPOSETo report the MR and CT findings in a hereditary disease, infantile-onset spinocerebellar ataxia (IOSCA).METHODSWe studied the brains of 17 patients with infantile-onset spinocerebellar ataxia with CT and/or MR to determine the presence of cerebellar and brain stem atrophy and parenchymal lesions.RESULTSCerebellar cortical atrophy was seen in 13 patients. The degree of atrophy correlated with increasing age and clinical deterioration. Brain stem atrophy was seen in 8 patients. It was never severe, and the basis pontis was not flattened even in the most severe cases. Hyperintense lesions were noted within the white matter of cerebellum, in the dentate nuclei, and in the middle cerebellar peduncles in 3 patients. The upper cervical cord was seen in 9 patients and showed mild to moderate atrophy in 4. The basal ganglia and cerebral hemispheres were normal, except in 2 patients transient cortical and subcortical lesions developed during episodes of status epilepticus; mild cortical brain atrophy subsequently developed.CONCLUSIONThe brain MR and CT findings of patients with infantile-onset spinocerebellar ataxia correspond to the neuropathologic entities of cerebellar cortical atrophy, olivopontocerebellar atrophy, and spinocerebellar atrophy. The appearance of the findings followed a uniform time sequence from cerebellar cortical atrophy in the early stage of the disease to olivopontocerebellar atrophy and spinocerebellar atrophy in the later stage. The severity of atrophy correlated with clinical deterioration.     

64层螺旋CT血管成像诊断脊髓血管畸形的价值

目的 探讨64层螺旋CT 血管成像(CTA)对脊髓血管畸形的诊断价值.方法 经临床和MR检查拟诊为脊髓血管畸形的15例患者进行了CTA.所有患者均在1周内进行了DSA检查.其中4例行于术治疗.将CTA图像与DSA和手术所见进行对照,从判定畸形的类型、显示病变累及的范围、供血动脉、引流静脉和可能存在的瘘口等方面,对CTA图像进行评价.结果 15例脊髓血管畸形经DSA和手术确诊,分别为6例髓内动静脉畸彤、2例髓周动静脉瘘、3例硬脊膜动静脉瘘和4例Cobb综合征.CTA对15例患者的分类和对病变累及范围的判断与DSA结果一致.CTA清晰显示了病变的主要供血动脉和引流静脉.5例动静脉瘘中4例CTA判断的瘘口位置与DSA所见一敛,另1例为复杂血管畸形,瘘口难以辨别.CTA还清晰显示了4例Cobb综合征位于椎旁和皮下的畸形血管团.结论 64层螺旋CTA可以判定脊髓血管畸形的类型,快速、无创地显示其主要病变特征,可作为该病的筛查手段.     

Cerebellar involvement in metabolic disorders: a pattern-recognition approach

Inborn errors of metabolism can affect the cerebellum during development, maturation and later during life. We have established criteria for pattern recognition of cerebellar abnormalities in metabolic disorders. The abnormalities can be divided into four major groups: cerebellar hypoplasia (CH), hyperplasia, cerebellar atrophy (CA), cerebellar white matter abnormalities (WMA) or swelling, and involvement of the dentate nuclei (DN) or cerebellar cortex. CH can be an isolated typical finding, as in adenylsuccinase deficiency, but is also occasionally seen in many other disorders. Differentiation from CH and CA is often difficult, as in carbohydrate deficient glycoprotein syndrome or 2-l-hydroxyglutaric acidaemia. In cases of atrophy the relationship of cerebellar to cerebral atrophy is important. WMA may be diffuse or patchy, frequently predominantly around the DN. Severe swelling of white matter is present during metabolic crisis in maple syrup urine disease. The DN can be affected by metabolite deposition, necrosis, calcification or demyelination. Involvement of cerebellar cortex is seen in infantile neuroaxonal dystrophy. Changes in DN and cerebellar cortex are rather typical and therefore most helpful; additional features should be sought as they are useful in narrowing down the differential diagnosis. Received: 17 September 1997 Accepted: 31 October 1997     

MR imaging of syringomyelia and hydromyelia

The relative effectiveness of plain computed tomography (CT), metrizamide CT, conventional myelography, and magnetic resonance (MR) imaging was compared for the examination of cystic spinal cord lesions. Intramedullary cavities in 18 patients were demonstrated by MR imaging: cavities were uncomplicated in 13 patients, associated with spinal tumors in two, and studied after occipital craniectomy for treatment of Chiari malformation and syringomyelia in two. Cavities were shown by MR imaging in all enlarged spinal cords, but a cavity was shown in only one of four small cords. The rostral limits of the cavities were demonstrated better than were the caudal extensions. Ventricular communication was not demonstrated. Chiari malformation was shown only in cavities that did not involve the medulla. Syringes associated with tumor were indistinguishable from uncomplicated cavities, but the tumor had abnormal signal on long spin-echo sequences in two cases. Cystic cord tumor (one case) had an inhomogeneous appearance. Caudal displacement of the cerebellar hemisphere through the surgical defect associated with compression of the fourth ventricle was shown in two cases after posterior fossa craniectomy. Thirteen patients were studied with metrizamide CT also. MR imaging proved to be as accurate as metrizamide CT in the diagnosis of intramedullary cavities that result in spinal cord enlargement, but it was less sensitive in detecting cavities within normal-sized or diminished spinal cords. It had the advantage that tumor tissue could be distinguished from associated syrinx cavities by differences in signal characteristics; and cerebellar ectopia was evaluated easily on sagittal MR views.