Atrophy of the corpus callosum correlates with white matter lesions in patients with cerebral ischaemia

Many studies of white matter high signal (WMHS) on T2-weighted MRI have disclosed that it is related to cerebral ischaemia and to brain atrophy. Atrophy of the corpus callosum (CC) has also been studied in relation to ischaemia. Our objective was to test the hypothesis that CC atrophy could be due to ischaemia. We therefore assessed CC, WMHS and brain atrophy in patients with risk factors without strokes (the risk factor group) and in those with infarcts (the infarct group), to investigate the relationships between these factors. We studied 30 patients in the infarct group, 14 in the risk factor group, and 29 normal subjects. Using axial T1-weighted MRI, cortical atrophy and ventricular enlargement (brain atrophy) were visually rated. Using axial T2-weighted MRI, WMHS was assessed in three categories: periventricular symmetrical, periventricular asymmetrical and subcortical. Using the mid-sagittal T1-weighted image, the CC was measured in its anterior, posterior, midanterior and midposterior portions. In the normal group, no correlations were noted between parameters. In the infarct group, there were significant correlations between CC and brain atrophy, and between CC atrophy and WMHS. After removing the effects of age, gender and brain atrophy, significant correlations were noted between some CC measures and subcortical WMHS. In the risk factor group, there were significant correlations between CC and brain atrophy and between CC atrophy and WMHS. After allowance for age, gender and brain atrophy, significant correlations between some CC measures and periventricular WMHS remained. The hypothesis that CC atrophy could be due to cerebral ischaemia was supported by other analyses. Namely, for correlations between the extent of infarcts and partial CC atrophy in patients with anterior middle cerebral artery (MCA) and with posterior MCA infarcts, there were significant correlations between the extent of infarct and midanterior CC atrophy in the former, and posterior CC atrophy in the latter. Our findings could indicate that CC atrophy is associated with cerebral ischaemia. Received: 5 December 1998/Accepted: 6 November 1999     

Leukoencephalopathy with swelling in children and adolescents: MRI patterns and differential diagnosis

In children, several neurological disorders are characterised by spongiform leukoencephalopathy. MRI of the brain typically shows white matter swelling, but does not enable differentiation of the various underlying disorders. The aim of this article is optimisation of the diagnostic value of MRI in leukoencephalopathy accompanied by swelling. MRI-based inclusion criteria were met by 20 patients in our database. The images were analysed using a detailed scoring list. In 13 of the 20 patients the clinical diagnosis was known (11 definite and 2 probable diagnoses). Characteristic MRI abnormalities could be defined in these patients. Of the 7 patients without a diagnosis, 5 had identical MRI abnormalities: difuse hemisphere swelling and typical cysts in frontoparietal subcortical white matter and the tips of the temporal lobes. The clinical picture was also similar in these patients, suggesting a similar disease.     

Sensitivity and reproducibility of a new fast 3D segmentation technique for clinical MR-based brain volumetry in multiple sclerosis

Fast, reliable and easy-to-use methods to quantify brain atrophy are of increasing importance in clinical studies on neuro-degenerative diseases. Here, ILAB 4, a new volumetry software that uses a fast semi-automated 3D segmentation of thin-slice T1-weighted 3D MR images based on a modified watershed transform and an automatic histogram analysis was evaluated. It provides the cerebral volumes: whole brain, white matter, gray matter and intracranial cavity. Inter- and intra-rater reliability and scan-rescan reproducibility were excellent in measuring whole brain volumes (coefficients of variation below 0.5%) of volunteers and patients. However, gray and white matter volumes were more susceptible to image quality. High accuracy of the absolute volume results (+/-5 ml) were shown by phantom and preparation measurements. Analysis times were 6 min for processing of 128 slices. The proposed technique is reliable and highly suitable for quantitative studies of brain atrophy, e.g., in multiple sclerosis.     

Computer-assisted segmentation of white matter lesions in 3D MR images using support vector machine

RATIONALE AND OBJECTIVES: Brain lesions, especially white matter lesions (WMLs), are associated with cardiac and vascular disease, but also with normal aging. Quantitative analysis of WML in large clinical trials is becoming more and more important. MATERIALS AND METHODS: In this article, we present a computer-assisted WML segmentation method, based on local features extracted from multiparametric magnetic resonance imaging (MRI) sequences (ie, T1-weighted, T2-weighted, proton density-weighted, and fluid attenuation inversion recovery MRI scans). A support vector machine classifier is first trained on expert-defined WMLs, and is then used to classify new scans. RESULTS: Postprocessing analysis further reduces false positives by using anatomic knowledge and measures of distance from the training set. CONCLUSIONS: Cross-validation on a population of 35 patients from three different imaging sites with WMLs of varying sizes, shapes, and locations tests the robustness and accuracy of the proposed segmentation method, compared with the manual segmentation results from two experienced neuroradiologists.     

颅内结节性硬化的CT诊断

结节性硬化是一种常染色体显性遗传性疾病。过去临床上主要靠病人有癫痫、智力低下和皮脂腺瘤三大体征来诊断。我们报告了CT诊断颅内结节性硬化15例。发现脑室管膜下钙化结节有15例,皮质结节5例,白质病灶4例。我们认为CT检查为临床诊断结节性硬化提供了有力的影像学依据。     

Whole-brain voxel-based morphometry of white matter in medial temporal lobe epilepsy

PURPOSE: The purpose of this study was to analyze whole-brain white matter changes in medial temporal lobe epilepsy (MTLE). MATERIALS AND METHODS: We studied 23 patients with MTLE and 13 age- and sex-matched healthy control subjects using voxel-based morphometry (VBM) on T1-weighted 3D datasets. The seizure focus was right sided in 11 patients and left sided in 12. The data were collected on a 1.5 T MR system and analyzed by SPM 99 to generate white matter density maps. RESULTS: Voxel-based morphometry revealed diffusively reduced white matter in MTLE prominently including bilateral frontal lobes, bilateral temporal lobes and corpus callosum. White matter reduction was also found in the bilateral cerebellar hemispheres in the left MTLE group. CONCLUSION: VBM is a simple and automated approach that is able to identify diffuse whole-brain white matter reduction in MTLE.     

Increased frequency of white matter lesions in patients with osteonecrosis (WMLeOn) of the femoral head

White matter lesions (WML) are commonly seen in cerebral MR imaging in normal and demented elderly people or young people suffering from migraine. We present data showing that WML are detected in an unexpectedly high frequency (56.9%) in patients with non-traumatic osteonecrosis of the femoral head compared to age and sex-matched controls. We designated the coexistence of WML and osteonecrosis as white matter lesions in osteonecrosis (WMLeON). We examined the possible association of WMLeON with hyperlipidaemia and other risk factors for WML or osteonecrosis of the femoral head. The frequency of history of corticosteroid treatment was statistically lower in patients with WMLeON (58.6%) compared to those without it (90.1%) (P=0.03). We found no association of WMLeON with diabetes, stroke, hyperlipidaemia, migraine, smoking, alcohol consumption, hypertension, atrial fibrillation, or systemic lupus erythematosus.

Although, the clinical significance of WMLeON is still unknown, this finding supports, at least, the hypothesis that non-traumatic osteonecrosis is indeed a multisystem disorder rather than a disease of human skeleton.     

Serial MR imaging in Creutzfeldt-Jakob disease

Summary Serial magnetic resonance (MR) imagings of two autopsied patients with Creutzfeldt-Jakob disease (CJD) are presented. Both patients showed a dramatic progression of brain atrophy. The initial MR imagings were, however, interpreted as normal except for localized mild cortical atrophy in one patient. When a normal MR image is obtained in a demented middle-aged or aged patient, CJD may still need to be ruled out: follow up MR imaging may be useful.     

Extensive white-matter changes in case of adult polyglucosan body disease

Extensive white matter signal changes were observed on T2-weighted images of a 49-year-old man. He presented with a slowly progressive gait disorder, and finally developed severe dementia. Extensive metabolic and infectious investigations failed to disclose the underlying cause during life. Autopsy revealed adult polyglucosan body disease. We discuss MRI findings likely to permit this diagnosis if combined with clinical findings and nerve or skin biopsy. Received: 14 July 2000 Accepted: 5 September 2000     

MRI in Cockayne syndrome type I

Summary MRI findings are reported from two patients with Cockayne syndrome (CS) type I, aged 11 and 37 years. Changes were compatible with diffuse white matter hypomyelination. Basal ganglia calcification was present in both, marked cerebellar atrophy in the older patient. MRI may support the diagnosis of CS in the appropriate clinical context. The view that CS is a dysmyelinating disorder is further substantiated.     

MR imaging of the brain: metabolic and toxic white matter diseases

Metabolic disorders of the brain are rare, complex and confusing. The diagnostic modality of choice nowadays is MRI. The high diagnostic sensitivity, however, is coupled with a lack of specificity and usually results in the depiction of similar appearing but clinically diverse white matter processes. For this reason it is essential to perform the MRI as early as possible during the course of the disease and to keep in close contact to the referring clinician to optimize image interpretation. Another precondition is to know the natural course of brain myelination and to know how this appears on the individual MR machine with different parameters. In some diseases like phenylketonuria MRI seems to be an excellent tool to monitor dietary treatment and patient compliance. In patients after radio- and / or chemotherapy MRI reveals the radiation induced leucencephalopathy and can usually differentiate between a recurrent malignancy.     

The occipital white matter lesions in Alzheimer's disease patients with visual hallucinations

PURPOSE: Investigators have suggested that lesions responsible for visual hallucinations (VHs) are situated in the visual association cortex. The aim of this study was to assess the relationship between occipital white matter lesions and VHs in Alzheimer's disease (AD) patients. METHODS: AD patients with a history of VHs (AD+VH) and those without (AD-VH) were retrospectively studied. The two groups of patients were matched by sex and mental state. All subjects underwent brain magnetic resonance image (MRI) scans. The periventricular hyperintensities (PVHs) and deep white matter hyperintensities (DWHs) on MRIs were rated by two raters using a semiquantitative scoring method (0=absent; 6=confluent). RESULTS: Five AD+VH patients and five AD-VH patients were enrolled into this study. The occipital PVH score was higher in the AD+VH patients than in the AD-VH patients. The occipital DWH score was zero in both groups. CONCLUSION: The presence of VHs in AD was associated with increased occipital PVHs and an absence of occipital DWHs on brain MRIs, implying that structural lesions in the geniculocalcarine region and preserved subcortical connections with visual association areas are involved in the genesis of VHs in AD.     

Fast FLAIR MRI in childhood white-matter abnormalities

We compared a fast fluid-attenuated inversion recovery (FLAIR) pulse sequence with a dual-echo short tau fast inversion-recovery (DESTTIR) sequence in 20 children with white matter abnormalities. Although the overall image quality of DESTTIR images was better, the lesion-to-background contrast was significantly higher with the fast FLAIR pulse sequence and lesion detection was more accurate. Received: 20 June 1997 Accepted: 1 October 1997     

Comparing brain white matter on sequential cranial ultrasound and MRI in very preterm infants

INTRODUCTION: Periventricular white matter (WM) echodensities, frequently seen in preterm infants, can be associated with suboptimal neurodevelopment. Major WM injury is well detected on cranial ultrasound (cUS). cUS seems less sensitive for diffuse or more subtle WM injury. Our aim was to assess the value of cUS and magnetic resonance imaging (MRI) for evaluating WM changes and the predictive value of cUS and/or MRI findings for neurodevelopmental outcome in very preterm infants with normal to severely abnormal WM on sequential high-quality cUS. MATERIALS AND METHODS: Very preterm infants (<32 weeks) who had sequential cUS and one MRI within the first three postnatal months were included. Periventricular WM on cUS and MRI was compared and correlated with neurodevelopmental outcome at 2 years corrected age. RESULTS: Forty preterm infants were studied; outcome data were available in 32. WM changes on sequential cUS were predictive of WM changes on MRI. Severely abnormal WM on cUS/MRI was predictive of adverse outcome, and normal-mildly abnormal WM of favorable outcome. Moderately abnormal WM on cUS/MRI was associated with variable outcome. Additional MRI slightly increased the predictive value of cUS in severe WM changes. CONCLUSION: Sequential cUS in preterm infants is reliable for detecting WM changes and predicting favorable and severely abnormal outcome. Conventional and diffusion-weighted MRI sequences before term equivalent age in very preterm infants, suggested on cUS to have mild to moderately abnormal WM, do not seem to be warranted.     

Pattern recognition in magnetic resonance imaging of white matter disorders inchildren and young adults

Summary Magnetic resonance imaging (MRI) is considered to be a highly sensitive modality for visualizing white matter abnormalities. Estimations of its specificity are far less positive. However, diagnostic specificity depends upon both the inherent qualities of MRI and on the quality of image interpretation. Systematic and detailed analysis of many image elements, and substantial prior experience improve the quality of image interpretation and thus improve diagnostic specificity. The present study has been set up to develop a pattern recognition system which combines sensitivity and specificity, systematic analysis of image elements and prior experience. This pattern recognition is based on the data of 277 patients with white matter disorders referred for MRI. The information was stored in a data base and computer analyzed. Twenty-two MRI patterns were discerned in as many disease categories. The frequency of occurrence of each MRI abnormality was assessed per disease category to establish the pattern of abnormalities characteristic for each separate disease category. The pattern recognition program was also written so that: (a) when fed data about MRI abnormalities observed in a new case, the computer produces a differential diagnosis with probabilities and 95% confidence intervals for each differential diagnosis; (b) specific data on the MRI findings of new cases could be added to the data base to improve the experience and accuracy of the program. This program for pattern recognition of abnormalities in the MR images of white matter disorders enhances the specificity of image interpretation and provides a wonderful aid for teaching purposes.     

飞行员与普通人脑白质高信号检出率及分布比较

目的：比较飞行员和普通人脑白质高信号（white matter hyperintensities,WMHs）的发病情况。方法收集2002年1月—2014年12月来空军总医院健康体检进行头颅MRI检查的现役飞行员290例、普通人910例进行回顾性分析,比较WMHs的发病情况。结果飞行员WMHs者40例,检出率为13.79%;普通人WMHs者83例,检出率为9.12%。飞行员和普通人WMHs年龄差异无统计学意义。本组飞行员和普通人WMHs分布部位类似,差异无统计学意义。本组40例WMHs飞行员蒙特利尔量表评分均≥26分。8例连续执行飞行任务飞行员6个月后WMHs体积增加,差异有统计学意义。结论本组飞行员WMHs的检出率高于普通人。飞行员和普通人WMHs分布部位类似主要位于额叶。飞行员点状WMHs对认知不受影响。飞行员WMHs的体积会随着飞行时间的增加而增加。     

扩散加权成像在新生儿早期脑白质损伤的诊断价值

目的:探讨磁共振扩散加权成像(diffusion-weighted imaging,DWI)在新生儿早期脑白质损伤的诊断价值.方法:选取有明确围生期窒息史,日龄≤7天的早产儿缺氧缺血性脑损伤(HIBD)412例、足月新生儿缺氧缺血性脑病(HIE)566例作为研究对象,另随机选取日龄相同临床及颅脑MRI检查结果正常的156例早产儿、227例足月新生儿作为正常对照组,全部行颅脑常规MRI和DWI检查.分别测量DWI上研究组异常高信号区和正常对照组同一位置表观弥散系数(ADC值).将两组ADC值分别计算其平均值±标准差,组间数据分别进行t检验分析,P值小于0.05表明有统计学意义.结果:①412例HIBD中382例常规MRI显示脑室旁短T_1信号.156例DWI表现为脑室旁、内囊前后肢、胼胝体膝压部有异常高信号占37.86%,病灶呈局灶性分布74例,弥漫性分布82例,其中30例常规MRI未见异常但在DWI显示异常;566例HIE中,轻度267例、中度206例、重度93例.DWI上表现为皮质下深部白质异常高信号为227例,病变显示率为40.1%,异常高信号呈局灶性分布150例,弥漫性分布77例,其中18例在常规MRI未见异常.②DWI上,HIBD灶状病变和弥漫性病变平均ADC值分别为(0.976±0.041)×10-3mm2/s,(0.949±0.039)×10-3mm2/s;HIE灶状病变和弥漫性病变平均ADC值分别为(0.639±0.108)×10-3mm2/s,(0.626±0.112)×10-3mm2/s,研究组脑白质异常高信号区平均ADC值分别显著低于正常对照组同一部位,P<0.05,表明ADC值研究组与正常对照组组间存在差异.结论:常规MRI检查与DWI序列结合可显著提高新生儿脑白质损伤的早期诊断率,为临床早期准确诊断脑瘫、早期干预、评估预后及康复治疗奠定基础.     

脑白质疏松的扩散张量成像(DTI)研究

目的 应用扩散张量成像（DTI）检查脑白质疏松（LA）病灶的平均扩散系数（DCavg）、各向异性（FA）值与LA严重程度的关系,探讨常规MBI检查正常的脑白质微结构在DTI中的变化及与认知功能的关系。资料与方法 对55例LA患者和22名健康老年人行DTI检查,测量LA病灶和正常白质区域的DCavg、FA值。结果 LA程度越严重,DCavg值越高,呈正相关;FA值越低,呈负相关。神经心理学测试（简易智能精神状态量表,MMSE）与LA患者的正常脑白质区域的DCavg、FA值明显相关,尤其是前角白质、半卵圆中心的正常脑白质。结论 DTI检查LA,其DCavg、FA值显示出特征性的改变,DTI能够发现常规MRI检查正常的脑白质微结构改变,且这种改变与认知功能相关。     

桥脑梗死患者基于体素的MRI形态学初步研究

目的：利用基于体素的形态学测量方法（VBM）,研究桥脑梗死患者病灶周围及其远隔部位的脑白质结构改变。方法：选取11例桥脑梗死患者分别于发病3～7天、15天、1月、3月进行MRI三维高分辨全脑容积扫描,选取性别、年龄匹配的健康志愿者作为对照组。测量桥脑梗死患者各期病灶体积,应用VBM方法测量脑白质密度,比较患者梗死灶体积以及全脑白质密度的改变。结果：随发病时间延长,桥脑梗死灶体积逐渐缩小,发病1月后病灶体积与发病初期比较显著减小（P〈0.05）。发病3月后与发病3～7天比较,梗死灶对侧内囊后肢、对侧小脑半球白质密度显著降低（P〈0.05）。桥脑梗死灶周围白质密度逐渐增高,有显著性差异（P〈0.05）。结论：应用VBM方法能够显示桥脑梗死后病灶周围及其远隔部位的脑白质密度改变,为研究脑梗死后神经功能恢复机制具有重要价值。