脑白质病变临床特点与白质传导束关系研究进展

脑白质病变(WML)是脑小血管病的一种,与年龄、高血压等血管危险因素相关。WML与脑卒中、记忆、语言、步态及情绪等有密切联系,而且其进展预示着临床预后较差。利用MR微细结构成像技术了解到脑白质传导束的病变与其多样化的临床表现相关。MRI技术为WML的病理生理机制提供了依据,为进一步了解WML多样化临床表现提供了新视角。     

缺血性脑白质病变的研究进展

缺血性脑白质病变是最常见的白质脑病类型之一。文章就其危险因素、发病机制、遗传学、临床表现、影像学、治疗等方面的进展做一综述。     

White Matter Changes in Depression and Alzheimer's Disease: A Review of Magnetic Resonance Imaging Studies

This article reviews magnetic resonance imaging (MRI) studies of white matter lesions in depression and Alzheimer's disease. Although conflicting reports exist, many studies show that white matter lesions are more prevalent in both conditions, with depression associated with deep white matter lesions (DWML) and Alzheimer's disease with periventricular lesions (PVL). In normal ageing and depression there is some evidence that such lesions may be associated with neuropsychological dysfunction, though the relationship is less clear for Alzheimer's disease. One difficulty in drawing firm conclusions from work so far is that confounding variables, such as cerebrovascular risk factors, have now always been taken into account. Most studies have been cross-sectional so there is little information regarding the progression, prognostic significance and pathogenesis of such lesions. These issues merit examination in longitudinal studies combining serial MRI with clinical assessments of subjects who have been fully assessed for vascular risk factors.     

Variability and Validity of a Simple Visual Rating Scale in Grading White Matter Changes on Magnetic Resonance Imaging

BACKGROUND AND PURPOSE: A new simple visual rating scale can be used in magnetic resonance imaging (MRI) to grade the severity of white matter changes (WMC). The authors sought to study the interobserver variability and the validity of this visual rating scale against a computer-aided quantitative method in measuring WMC. METHODS: The authors examined 220 magnetic resonance images from stroke-free patients with traditional risk factors for atherosclerosis and middle cerebral artery stenosis who were participants in a clinical trial requiring MRI examination. The severity of WMC was graded from 0 (no WMC) to 3 (severe WMC). For the quantitative assessment of WMC, the volume of WMC were measured with a computer-aided, automated segmentation method. The interobserver variability was also determined. RESULTS: The mean volumes were significantly different among the different groups, which were scored 1, 2, and 3 (1324.59, 6475.48, and 25,440.05 mm3, respectively; 1-way analysis of variance, P < .001). Interobserver variability for grading WMC was good in different locations of the brain. Excellent results were found in the frontal lobe (kappa = 0.829) and the parietal-occipital lobe (kappa = 0.646), whereas poor results were found in the basal ganglia (kappa = 0.391). There was perfect agreement between the 2 observers in 89.1% for the frontal lobe and 77.0% for the parietal-occipital lobe. CONCLUSIONS: The results suggest that this simple visual rating scale is a valid and reliable method for grading WMC in the lobar region but not in the basal ganglion.     

老年人脑白质改变的危险因素及其与认知功能障碍的相关性研究

目的探讨老年人(≥75岁)脑白质改变(WMC)发生的危险因素及其与认知功能障碍的相关性。方法根据影像学改变选择WMC患者76例(WMC组)和无WMC者74例(对照组)为研究对象。对WMC组进行影像学Fazekas视觉等级评分,根据评分将WMC分为轻度、中度和重度。采用Logistic法分析WMC发生的危险因素。应用神经心理学量表评估分析WMC对认知功能的影响。结果与对照组比较,WMC组的年龄、高血压病、糖尿病、纤维蛋白原水平差异有显著统计学意义(分别P=0.003、P0.001、P=0.006、P0.001)。Logistic分析发现年龄、高血压病、纤维蛋白原水平是WMC的独立危险因素。WMC组的简明精神状态检查、蒙特利尔认知评估、画钟试验、6项躯体性日常生活能力、8项工具性日常生活能力等认知功能量表检测均差异有显著统计学意义(均P0.001),在校正年龄等因素后仍存在差异。结论年龄、高血压病、糖尿病、纤维蛋白原水平与老年人WMC有关,年龄、高血压病、纤维蛋白原水平升高是WMC的独立危险因素。中、重度WMC可引起≥75岁老年人认知功能和日常生活能力下降。     

Relationship Between Cerebral Vasomotor Reactivity and White Matter Lesions in Elderly Subjects Without Large Artery Occlusive Disease

BACKGROUND AND PURPOSE: The relationships between cerebral vasomotor reactivity (CVR) and white matter lesions (WMLs) were investigated mainly in patients with carotid stenosis. We aimed to study the relationship in asymptomatic elderly subjects without large artery occlusive disease. METHODS: A total of 33 elderly individuals (mean age was 76.2 years) who were free from neurological deficit or cognitive impairment were studied. Bilateral mean blood flow velocity was measured in the middle cerebral artery using a 2-MHz pulsed transcranial Doppler (TCD) system together with intravenous administration of acetazolamide as vasodilatory stimuli. WMLs on a fluid-attenuated inversion recovery (FLAIR) sequence of MRI were classified into two categories: subcortical deep white matter hyperintensity (SDWMH) and periventricular hyperintensity (PVH). The lesions in each category were then divided into three grades (grade 0-I, grade II, grade III) according to the Fazekas scale. RESULTS: CVR was inversely associated with the extent of SDWMH and PVH. The differences in CVR were statistically significant among different severity of WMLs: for SDWMH (70%+/- 10% in grade 0-I, 60%+/- 10% in grade II, and 40%+/- 10% in grade III, P < .001); for PVH (80%+/- 10% in grade 0-I, 60%+/- 10% in grade II, and 40%+/- 10% in grade III, P < .001). CONCLUSIONS: Impaired CVR is related to the extent of WMLs in asymptomatic elderly individuals without large artery stenosis. The findings in our study suggest that dysfunction of cerebral vascular autoregulation might be an important factor in the development of WMLs in the asymptomatic elderly without large artery occlusive disease.     

Magnetic Resonance Imaging White Matter Hyperintensity as a Predictor of Stroke Recurrence in Patients with Embolic Stroke of Undetermined Source

Background and Purpose

This study aimed to investigate factors associated with stroke recurrence and new-onset atrial fibrillation (AF) in patients with embolic stroke of undetermined source (ESUS).

小血管病性脑白质病变与认知功能障碍关系研究

目的 评估小血管病患者脑白质病变程度与认知功能的相关性。 方法 通过对浙江大学医学院附属第一医院神经内科门诊患者进行老年人认知功能下降知情者问 卷（informant questionnaire on cognitive decline in the elderly,IQCODE）、简易智能状态检查量表（minimental state examination,MMSE）、临床痴呆评定量表（clinical dementia rating,CDR）评分以及相关认 知功能评估,结合头颅磁共振成像（magnatic resonance imaging,MRI）检查及临床资料,筛选小血管病 变患者,并通过相关统计分析计算不同部位脑白质病变的程度及其对认知功能的影响。 结果 本研究共纳入患者147例,其中小血管病变（cerebral small vessel disease,SVD）患者33例,SVD患 者记忆力（z =-3.36）、定向力（z＝-3.14）、处理判断力（z =-3.38）以及社会事物能力（z =-3.22）较 正常者都明显下降（P =0.00）。脑室周围病变与MMSE分数（r =0.82）、CDR总分（r =0.62）、CDR记忆分 （r =0.82）显著相关（P值均=0.00）,皮质下病变与MMSE分数（r =0.51,P =0.01）、CDR记忆分（r =0.49, P =0.02）中度相关。 结论 在脑小血管病患者,MMSE评分、CDR评分对于脑白质病变特别是脑室旁病变的进展可能具有 一定的预测价值。     

Correlation Between White Matter Lesions and Intelligence Quotient in Patients With Congenital Cytomegalovirus Infection

BackgroundIt is well known that congenital cytomegalovirus infection exhibits white matter and other types of lesions in magnetic resonance imaging (MRI), but little is known on the clinical significance of white matter lesions because they are also present in asymptomatic congenital cytomegalovirus infection. We investigated for relationships among white matter lesions, intelligence quotient, and other neurodevelopmental features.MethodsNine children (five boys and four girls; mean age: 87.4 months, range: 63-127 months) with sensorineural hearing loss (five bilateral and four unilateral) had been diagnosed as having congenital cytomegalovirus infection by positive polymerase chain reaction findings of dried umbilical cords. They were evaluated for the presence of autistic features, tested using Wechsler Intelligence Scale for Children–Fourth Edition for intelligence quotient, and underwent brain MRI to measure white matter lesion localization and volume.ResultsAt the time of MRI examination (mean age: 69.4 months, range: 19-92 months), white matter lesions were detected in eight of nine patients. Five subjects were diagnosed as having autism spectrum disorders. We observed increased white matter lesion volume was associated with lower intelligence quotient scores (R² = 0.533, P = 0.026) but not with autism spectrum disorders.ConclusionsIn individuals with congenital cytomegalovirus, an increased white matter lesion volume is associated with lower intelligence quotient scores but not with an increased likelihood of autistic behavior.     

White Matter Lesions in Children and Adolescents With Migraine

BackgroundThe etiology and clinical importance of white matter lesions in migraine remain poorly understood. To understand these issues more fully, we reviewed the brain magnetic resonance imaging scans of pediatric patients and assessed the relationships between white matter lesions, migraine type, patent foramen ovale, and right-to-left shunting.MethodsThe magnetic resonance imaging scans of a cohort of children (n = 89) and adolescents, ages 6 to 18 years, who participated in a study of migraine and patent foramen ovale were reviewed. All children in the cohort had undergone saline contrast transthoracic echocardiography and transcranial Doppler studies.ResultsWhite matter lesions were detected in 15 of the 89 patients (17%). White matter lesions were small (<5 mm) in the majority (10/15; 66%). We observed no relationship between the presence of white matter lesions and (1) migraine type (six patients with white matter lesions among 35 with migraine with aura [17%] vs. nine with white matter lesions among 54 without aura [17%]; P = 1.0); (2) patent foramen ovale (five with white matter lesions among 35 with patent foramen ovale [14%] vs. 10 with white matter lesions among 54 without patent foramen ovale [19%]; P = 0.77); or (3) shunt size (two large shunts in 15 with white matter lesions [13%] vs. nine large shunts among 72 without white matter lesions [13%]; P = 1.0).ConclusionsThese results indicate that small white matter lesions are not infrequent in children and adolescents with migraine. However, no relationships between white matter lesions and migraine type, patent foramen ovale, or degree of right-to-left shunting were observed.     

定量脑电图对脑白质损害患者认知功能障碍的诊断价值

目的探讨定量脑电图对脑白质损害(WMLs)患者认知功能障碍的诊断价值。方法纳入WMLs患者152例(WMLs组),再依据Fazekas分级分为3个亚组:Fazekas 1级亚组(45例)、Fazekas 2级亚组(52例)和Fazekas 3级亚组(55例);另选择同期门诊体检及头颅MRI阴性的健康人群为对照组(45例)。所有研究对象均进行定量脑电图分析和MoCA量表认知功能测试,并采集相关数据进行统计学分析。结果 Fazekas 1级亚组MoCA量表各项评分与对照组比较差异无显著性;Fazekas 2级亚组在MoCA量表总分、视空间与执行能力、命名、注意力、复述、延迟记忆、抽象理解等7项评分低于对照组(P0.05);Fazekas 3级亚组MoCA量表总分及各项评分均显著低于对照组和Fazekas2级亚组(P0.05)。Fazekas 2级亚组和Fazekas 3级亚组额区、中央区、颞区、顶区及枕区的功率谱比值显著低于对照组(P0.05),其功率谱比值与MoCA量表评分呈中度正相关关系(r=0.411~0.593,P0.05)。结论定量脑电图与MoCA量表评估WMLs存在相关性,可用于脑白质损害患者认知功能障碍的诊断和评估。     

脑白质病变患者认知功能的前瞻性研究

目的 探讨不同部位和严重程度脑白质病变（white matter lesions,WMLs）患者的认知功能损害特点。 方法 前瞻性纳入179例WMLs病例和97例磁共振成像（magnetic resonance imaging,MRI）正常对照组, 并收集人口学资料,对WMLs的严重程度进行Fazekas视觉等级评分,依据WMLs病变部位分为皮质下脑 白质病变（subcortical white matter lesions,SWML）组、脑室旁脑白质病变（periventricular lesions,PVL）组 和混合组,采用蒙特利尔认知评估量表（Montreal Cognitive Assessment Scale,MoCA）分析不同部位和 严重程度WMLs的认知功能差异。根据MoCA将WMLs组分为WMLs认知损害亚组（116例）及WMLs认知正 常亚组（63例）,分析探讨WMLs患者认知损害的危险因素。 结果 与正常组比,WMLs组在MoCA总分（P ﹤0.001）、视空间与执行能力（P ﹤0.001）、命名（P =0.019）、 语言（P =0.005）、抽象理解（P =0.003）、延迟记忆（P ﹤0.001）方面显著性减低。Fazekas分级越高, MoCA总分及各项评分显著减低（P均﹤0.05）。PVL组、SWML组和混合组与对照组相比,在MoCA总分（P 均﹤0.001）、视空间与执行能力（P 均﹤0.001）、语言（P =0.006,0.022,0.008）、抽象理解（P =0.003, 0.011,0.016）及延迟记忆（P均﹤0.001）上差异有统计学意义。WMLs亚组分析显示高教育程度是WMLs发 生认知损害的保护因素。 结论 高教育程度是WMLs患者认知损害的保护因素。WMLs患者在视空间与执行功能、延迟回忆方面 存在明显的认知损害。WMLs病变程度越严重,认知功能下降越显著。皮质下WMLs、脑室旁WMLs及混 合组均在视空间与执行能力、语言、抽象理解、延迟记忆方面损害严重。     

Interobserver Agreement in Magnetic Resonance Brain and Neck Imaging

AIM: To investigate the interobserver reliability of brain and neck magnetic resonance imaging (MRI) in older community subjects previously recruited to a case-control study of dizziness. METHODS: Subjects aged over 65 years were identified through a local survey and advertising. Several investigations were performed, including MRI of the head and neck using a Siemens 1.5 Tesla machine. Images were coded independently by two consultant neuroradiologists. Interobserver agreement was calculated using kappa statistics. RESULTS: Of the 246 participants, scans from 84 dizzy subjects and 79 non-dizzy subjects were available for coding by two neuroradiologists. Agreement was "fair" for cerebral atrophy, "good" for white matter lesions (WML) in the cerebral hemispheres, and moderate for WML in the posterior fossa. Agreement for cervical spine disease ranged from "moderate" (severity of cord compression) to "poor" (vertebral artery occlusion). CONCLUSION: Interobserver variability in the evaluation of brain and cervical cord MRI was substantial. The development of standardized scores, particularly for disease of the cervical cord, may improve interobserver reliability.     

Prevalence of White Matter Hyperintensities in a Young Healthy Population

BACKGROUND AND PURPOSE: White matter hyperintensities (WMHs) are bright objects observed in the white matter on brain magnetic resonance (MR) imaging. WMHs are often reported as "normal" findings but may represent pathological changes. The prevalence of WMHs appears to increase with increasing age although both the typical timing and clinical significance of their appearance among medically and neurologically healthy persons remains unclear. We assessed the prevalence of WMHs in a cohort of younger healthy subjects. METHODS: Our study comprised 243 healthy subjects ages 16-65 years from our prospective normative MR imaging database. MR scans were rated for presence of periventricular and centrum semiovale WMHs using a four-point visual semi-quantitative scale. RESULTS: WMHs occurred in 5.3% (13 of 243) of subjects. All WMHs were small (rating of 0.5) except one subject age 65 years who had large WMHs (ratings of 2). The median age for subjects with no WMHs was 34.5 years compared to 57.0 years for subjects with WMHs. There were no gender differences (P= .76). Older age correlated with presence of WMHs (r = 0.24; P= .01). Age greater than 55 years had a 10-fold increase in the prevalence of WMHs compared to age < or =55 years (odds ratio = 10.01; 95% confidence interval = 3.1-32.3; P < .001). CONCLUSION: WMHs were uncommon in a younger healthy population screened for comorbid diseases, but increased 10-fold in subjects over 55 years of age. When present, the WMHs are generally small (rating of 0.5). While large WMHs appear to be associated with cognitive deterioration, the optimum threshold for identification, clinical significance, and prognostic value of smaller white matter changes requires further research.