Braille alexia during visual hallucination in a blind man with selective calcarine atrophy

The case of a 56-year-old man who has been blind for 25 years due to retinal degeneration is herein described. The patient complained of elementary visual hallucination, during which it was difficult for him to read Braille. Brain magnetic resonance imaging showed marked atrophy of the bilateral striate cortex. Visual hallucination as a release phenomenon of the primary visual cortex has never been reported to cause alexia for Braille. The present case supports the results of recent functional imaging studies of the recruitment of striate and prestriate cortex for Braille reading.     

Wallerian degeneration of the pyramidal tract in capsular infarction studied by magnetic resonance imaging

Using magnetic resonance imaging, we studied 24 patients with ischemic infarction of the internal capsule. Magnetic resonance imaging detected wallerian degeneration of the pyramidal tract below the capsular lesion in 11 patients (45.8%); all 11 had clinical evidence of pyramidal tract damage. In six additional patients magnetic resonance imaging findings, present only on axial slices, were considered to indicate possible wallerian degeneration. When motor deficit was associated with posterior limb lesions, magnetic resonance imaging detected wallerian degeneration of the pyramidal tract in 78.6% (11) of 14 patients.     

亚急性脊髓混合变性的17例临床特征和诊断

目的评价亚急性脊髓混合变性（ＳＣＤ）的临床特征及电生理和磁共振成像的诊断价值。方法回顾分析了１７例ＳＣＤ患者的临床表现。结果发现全部ＳＣＤ患者发病由维生素Ｂ１２缺乏引起，胃大部切除术是一个主要病因，肢体感觉异常和深感觉减退是ＳＣＤ最常见的症状和体征，１２例合并周围神经损害，５例合并植物神经损害，体感诱发电位有极高的敏感性，磁共振成像可以明确脱髓鞘的部位。结论电生理和磁共振检查对ＳＣＤ的诊断和治疗起重要作用     

Radiological and histopathological examination of early tissue reactions to absorbable hemostatic agents in the rabbit brain.

Topical hemostatic agents are widely and safely used in neurosurgery. The purpose of this study was to compare and analyse the early tissue reactions to two hemostatic agents, oxidized regenerated cellulose and gelatin sponge, in rabbit brain by magnetic resonance imaging and histopathologic sections. Bilateral identical parenchymal lesions were made in the frontal regions of each hemisphere in 13 rabbits. Hemostasis was achieved using oxidized regenerated cellulose or gelatin sponge, one agent being used on each side. Cranial magnetic resonance imaging was performed 24 h postoperatively and there was no statistical difference in edema formation at the site of the lesions. Histopathologic examinations indicated that pericapillary edema and endothelial distortion were common in both groups but that there was additional tissue degeneration evident in the regions where gelatin sponge had been used. Oxidized regenerated cellulose seemed to cause greater tissue distortion in magnetic resonance images than gelatin sponge but in contrast, histological examination of lesions in which oxidized regenerated cellulose had been used revealed less tissue degeneration than histopathologic examinations of lesions in which gelatin sponge had been used.     

Axonal degeneration in large and small nerve fibres. An electron-microscopic and morphometric study

Using computer-aided morphometric methods, axonal degeneration following nerve crush was analysed to reassess whether small fibres degenerate before large fibres or vice versa, or simultaneously. Axonal microtubule density was used as the criterion for determining the extent of fibre degeneration. Axonal areas and axonal microtubule numbers were recorded from a large sample of myelinated fibres in the right unoperated rat sural nerve and distal to crush in the left sural nerve. Both samples were divided into small and large fibre groups, according to axonal areas. Statistical analysis of the data confirmed a significant loss of microtubules from the left crushed nerve fibres but no significant difference in the relative loss of microtubules from small and large fibres. It is concluded, therefore, that in Wallerian degeneration, axonal breakdown, as assessed by microtubule loss, occurs simultaneously in small and large fibres. The findings are related to the electrophysiological changes which occur in Wallerian degeneration.     

Prominent cerebellar symptoms with unusual magnetic resonance imaging findings in acquired hepatocerebral degeneration

BACKGROUND: Cerebellar lesions revealed by abnormal signals on magnetic resonance images are extremely rare in acquired hepatocerebral degeneration (AHCD). OBJECTIVE: To report a case of AHCD with prominent cerebellar findings both clinically and radiologically. DESIGN AND SETTING: Case report and tertiary-care hospital. PATIENT: A 46-year-old man complained of progressive speech difficulties of 5 months' duration. Two years earlier, he had been diagnosed as having cirrhosis of the liver caused by alcoholism and hepatitis B virus infection. RESULTS: The patient had progressive ataxic dysarthria and limb and gait ataxia as manifestations of AHCD. Magnetic resonance imaging of the brain revealed distinctive symmetrical T2 high-signal intensities in the bilateral cerebellar hemispheres and brachium pontis, which were consistent with his neurologic deficits. Simultaneously, high T1 signals in the bilateral pallidum and ventral midbrain were noted, which are typical manifestations of AHCD. Follow-up magnetic resonance imaging 3 months later showed the same cerebellar signs and abnormal signals. CONCLUSIONS: The cerebellar cortex and middle cerebellar peduncle are considered highly vulnerable structures to metabolic insults in liver disease. Findings from our patient suggest that dominant cerebellar deficits with compatible T2 high-signal lesions are another type of clinical manifestation in AHCD.     

A case showing Wallerian degeneration of the bilateral middle cerebellar peduncles on MRI followed by the right pontine infarction]

We report a 63-year-old man who presented with the left facial palsy, the left hemiparesis, the left limb ataxia, and the bilateral truncal ataxia. On admission, magnetic resonance imaging (MRI) showed an abnormal high intensity lesion at the right paramedian region of the upper to middle pons on T2-weighted images (T2WI). He was diagnosed as having a pontine lacunar infarction. The contralateral cerebellar lesions were caused by involvement of the pontocerebellar fibers. On the 29th day from the onset, MRI showed the new abnormal high intensity lesions at the bilateral middle cerebellar peduncles on T2WI. These lesions were supposed to be Wallerian degeneration caused by involvement of the pontocerebellar fibers. This case suggests that Wallerian degeneration occurs followed by a unilateral infarction involving pontocerebellar fibers.     

Ataxic variant of adrenoleukodystrophy: MRI and CT findings

Summary A 28-year-old man developed slowly progressive dysarthria and gait disturbance over 7 years. Neurological examination revealed marked ataxia of articulation and gait, mild ataxia and spasticity of all four limbs without intellectual, visual, auditory, sensory or sphincter dysfunction. No physical signs of adrenal hypofunction were found. However, analysis of fatty acid of plasma sphingomyelin showed an increase in very long chain fatty acids, compatible with the diagnosis of adrenoleukodystrophy. Computed tomography disclosed marked atrophy of the cerebellum and pons, and bilateral low-density lesions in the deep while matter of the cerebellum. Magnetic resonance imaging showed these lesions more clearly, as well as other lesions in the middle and superior cerebellar peduncles, despite the absence of cerebral white matter involvement at the time of presentation. This is a rare case of adrenoleukodystrophy presenting as spinocerebellar degeneration and showing marked atrophy and several parenchymatous lesions of the cerebellum and brain stem.     

动脉自旋标记技术在血管源性脑白质高信号中的研究进展

脑小血管病（CSVD）是指累及脑的小动脉、穿支动脉、毛细血管及小静脉等小血管的各种结构或功能性的病变，导致相应临床、认知、影像及病理表现的综合征。血管源性脑白质高信号（WMH）是当前最为广泛认可的CSVD影像学标志物，多数研究认为慢性脑血流低灌注是WMH潜在病理机制之一。该文介绍磁共振成像的一个新的技术——动脉自旋标记技术（ASL）的基本原理，重点介绍ASL技术在WMH中的应用进展，对单一ASL及ASL联合多模态磁共振技术，如弥散张量成像（DTI）、血氧水平依赖磁共振（BOLD）、基于体素的形态学分析（VBM）、动态对比增强磁共振（DCE）在WMH中的应用进行综述，为进一步了解WMH相关机制、早期诊断和早期干预等提供依据。     

Paraneoplastic cerebellar degeneration in Hodgkin's lymphoma

Paraneoplastic cerebellar degeneration (PCD) is a rare disorder presenting typically with acute or subacute severe cerebellar ataxia. PCD is most commonly associated with small cell lung cancer followed by adenocarcinoma of breast and ovary, and Hogdkin''s lymphoma. We report a case of a 54-year-old male with acute-onset pancerebellar syndrome with underlying Hodgkin''s lymphoma. A high index of suspicion of PCD resulted in arriving at an early diagnosis of underlying Hodgkin''s disease. The patient was managed with six cycles of chemotherapy, which resulted in clinical stabilization and reversal of magnetic resonance imaging abnormalities. Antitumor therapy appears to have a significant impact on reversing PCD and hence early diagnosis and intervention for the primary remains the corner stone in stabilizing the neurological condition.     

Paraneoplastic cerebellar degeneration associated with Hodgkin's disease

Summary A case of paraneoplastic cerebellar degeneration (PCD) associated with Hodgkin's disease is presented. The features that make this case particularly interesting are the simultaneous occurrence of PCD with a relapse of Hodgkin's disease, which has been present for 17 years, and the arrested progression of cerebellar dysfunction after a subacute onset. Cerebellar atrophy was revealed by computed tomography and magnetic resonance imaging. In contrast to two previously reported cases, anti-Purkinje-cell antibodies were not detected.     

Progressive multifocal leukoencephalopathy and magnetic resonance imaging

Progressive multifocal leukoencephalopathy developed in a homosexual man with underlying Hodgkin's disease. Computed tomography and magnetic resonance imaging of the brain demonstrated multiple lesions, more in gray than white matter. Brain biopsy established the diagnosis of progressive multifocal leukoencephalopathy. Magnetic resonance imaging was found useful for detecting brain lesions and for localizing an accessible lesion for biopsy.     

Deterioration on magnetic resonance imaging despite good clinical recovery after viral encephalitis

We present a 2-year-old patient who showed progressive widespread white-matter abnormalities on magnetic resonance imaging 1 month after viral encephalitis, despite her good clinical recovery. These lesions on magnetic resonance imaging had not responded to therapies commonly used to treat secondary immune-mediated demyelinating lesions, as observed in acute disseminated encephalomyelitis. Acute viral encephalitis caused cortical blindness, but no other clinical signs developed during her clinical course. The progressive white-matter lesion in our case was different from the exacerbation of viral encephalitis or secondary immune-mediated encephalitis. A year later, magnetic resonance imaging-demonstrated brain atrophy with cystic changes in the bilateral occipital area, with remarkably reduced white-matter lesions. We hypothesize that the progressive white-matter changes resulted from the process of atrophy, degeneration, and cystic formation after viral encephalitis, rather than from the immune-mediated demyelinating process.     

Cheiro-oral syndrome due to lesions in the corona radiata.

BACKGROUND AND PURPOSE: We describe three patients with cheiro-oral syndrome caused by a small lesion in the corona radiata confirmed by high-resolution magnetic resonance imaging. CASE DESCRIPTIONS: Case 1: A 56-year-old hypertensive man who developed hypesthesia and paresthesia in the left perioral area and hand was found to have a small hematoma just lateral to the right internal capsule. Case 2: A 67-year-old man noticed hypesthesia around the left mouth angle and thumb and index finger. Magnetic resonance imaging revealed a lesion in the right corona radiata. Case 3: A 45-year-old hypertensive man developed numbness in his perioral region and left hand that later spread to his shoulder. Magnetic resonance imaging revealed a recent small infarct in the lower lateral aspect of the right corona radiata. CONCLUSIONS: A small lesion in the corona radiata can cause cheiro-oral syndrome, whose pathogenetic mechanism in such patients may be explained by the somatotopical location or by the differing vulnerability of the neuropils in the corona radiata.     

胼胝体病变-肝豆状核变性的少见脑部影像学表现

目的研究肝豆状核变性患者胼胝体病变及其临床价值。方法收集3例肝豆状核变性患者的临床及影像资料,参照2001年第八届莱比锡肝豆状核变性国际会议制定的诊断评分系统评分。利用磁共振成像(MRI)技术检查胼胝体压部病变。结果 3例患者均存在胼胝体压部病变,但均无胼胝体病变所致的失连接综合征表现。头颅MRI技术提示3例患者胼胝体病变主要为长T2异常信号、FLAIR像稍高信号,其中1例DWI呈高信号。出现胼胝体病变的3例肝豆状核变性患者均病情较重、脑部损伤弥漫(尾状核、壳核、苍白球、丘脑、中脑及桥脑)。结论胼胝体病变为肝豆状核变性患者少见的影像学表现,若在有典型基底节病变的同时还伴有胼胝体病变则高度支持肝豆状核变性的诊断。胼胝体病变也提示患者病情较重、脑部损伤弥漫,预后相对较差。     

Progressive Brainstem Disease in a 32-Year-Old Man with a Pituitary Adenoma and Longstanding Diabetes Insipidus

A 32-year-old man who had unexplained diabetes insipidus for 14 years developed hypogonadism and was found to have a pituitary adenoma. Shortly thereafter he noted a progressive brainstem syndrome. Computed tomography and magnetic resonance imaging revealed lesions in the pituitary fossa and brainstem. Dr Keith A. Sanders discusses the differential diagnosis of these lesions, focusing on the significance of diabetes insipidus in a patient with a pituitary tumor, and the specificity of magnetic resonance imaging. Dr Michael R. Fetell discusses the histopathological findings and clinical pathological correlations in this unusual case.     

Substantia nigra lesions in viral encephalitis.

Post-encephalitic parkinsonism is a well-known entity, but involvement of the basal ganglia is rarely documented. We describe a 21-year-old man who developed parkinsonism following encephalitic illness presumed to be of viral origin with substantia nigra lesions evident on magnetic resonance imaging scan.     

纹状体梗死后黑质继发性损害的磁共振表现与意义

目的探讨常规磁共振(conventional magnetic resonance imaging,MRI)检测纹状体梗死后黑质继发性损害的敏感性及其影像学特点。方法对首次发病、确诊为单侧基底节区新发纹状体梗死患者,分别在急性期(7 d)、亚急性期(8～21 d)及慢性期(3个月以后)进行1次或多次常规MRI检测,分析其MRI资料。结果本研究中纹状体梗死患者70例,MRI检测提示黑质继发性损害患者27例(38.57%),2例患者出现双上肢齿轮样肌张力升高、面部表情缺失、等类似帕金森病样症状。纹状体梗死后黑质继发性损害的MRI表现为,梗死灶同侧黑质在急性期、亚急性期在T2及FLAIR出现斑片状高信号改变,而且该信号改变在慢性期逐渐消失。结论纹状体梗死后黑质的继发性损害在MRI上有特征性改变,而且可能参与血管性帕金森综合征的发病过程。     

Imaging of axonal damage in multiple sclerosis: Spatial distribution of magnetic resonance imaging lesions

We performed magnetic resonance imaging and magnetic resonance spectroscopic imaging on 28 patients with multiple sclerosis stratified for disability and clinical course (relapsing with at least partial remissions or secondary progressive disease). Lesions were segmented on the conventional proton density and T2-weighted magnetic resonance images, and lesion distribution images were generated for each patient. The conventional magnetic resonance and spectroscopic images were transformed into a standard brain-based stereotaxic coordinate space, allowing comparison of images from different patients on a voxel-by-voxel basis. The spatial distribution of lesions in the transformed magnetic resonance images did not differ significantly between the relapsing and the progressive disease groups. We then generated from the individual data sets, group lesion probability distribution images for the relapsing and the progressive disease groups. The spatial distribution of metabolites was characterized with respect to lesion distribution using the magnetic resonance spectroscopic images transformed into stereotaxic space and averaged. The neuronal marker N-acetylaspartate was diffusely lower in the multiple sclerosis patients than in normal control subjects. Comparison of the averaged metabolite and T2-weighted lesion probability images confirmed loss of N-acetylaspartate in regions of both high and low lesion probability. This suggests that diffuse axonal volume loss or dysfunction extends beyond the inflammatory lesions of multiple sclerosis, perhaps due to microscopic disease or wallerian degeneration along projection pathways of axons traversing the lesions.