White matter magnetic resonance imaging hyperintensity in Alzheimer's disease: correlations with corpus callosum atrophy

We have previously demonstrated with MRI that as well as marked white matter involvement in late-onset Alzheimer's disease (AD), atrophy of the corpus callosum may also be present. This finding prompted us to study possible correlations between atrophy of the corpus callosum and white matter hyperintensity (WMH) and between white matter lesions and the severity of the disease. We compared the corpus callosum and white matter lesions on MRI from 15 AD patients and 15 controls. The white matter lesions were scored according to the Scheltens' rating scale. We found a significant reduction of the area of the corpus callosum and more severe white matter lesions in AD patients than in controls. Both atrophy of the corpus callosum and the severity of lesions depended mainly on the diagnosis of senile dementia of the Alzheimer type and on age but not on the diagnosis of presenile AD. We demonstrated a negative correlation between white matter lesions scores and areas of corpus callosum in AD patients and no correlation between the white matter lesions and the severity of the disease. We demonstrated that white matter lesions including WMH and atrophy of the corpus callosum are more frequent in AD than in controls. The predominance of white matter lesions in senile AD may be explained by the combination of aging and disease processes.     

阿尔茨海默病脑磁共振研究

目的 了解Ａｌｚｈｅｉｍｅｒ病（ＡＤ）脑结构性变化的特点及与健康老人增龄性改变的差异。方法 对２２例ＡＤ和２９例健康老人分别按年龄为６０～６５岁、６６～７０岁和７０岁以上三组,ＡＤ为ａｄ１、ａｄ２和ａｄ３组,健康老人为ｎｏｒ１、ｎｏｒ２和ｎｏｒ３组。全部对象作ＭＲＩ检查。结果 ｎｏｒ３的灰质体积、总脑脊液体积及右侧海马体积与ｎｏｒ１和ｎｏｒ２相比有显著差异;与健康老人相比,ＡＤ的灰质体积,双侧海马体积显著降低,而总脑脊液、脑室外脑脊液、侧脑室、三脑室和四脑室体积显著升高。结论 与健康老人增龄性变化相比,ＡＤ脑结构性改变的涉及范围广,变化幅度大。     

Magnetic resonance imaging and computed tomography in Alzheimer's disease

Structural neuroimaging with CT and MRI plays an important role in the routine clinical investigation of dementia patients. One major purpouse of the technique is to exclude secondary, treatable dementia disorders. In this respect these techniques are of utmost importance. Another major purpose of these techniques is to differentiate AD from healthy controls and other dementias.
Although some research groups have reported a high sensitivity and specificity for diagnosing AD by measuring the volumes (with MRI) of structures in the temporal lobes, there are no unequivocal "radiological" markers (such as the size of the lateral ventricles or sulci) that can differentiate AD from controls or vascular dementia. There have been a large number of CT and MRI studies showing that the volumes of the temporal lobes or part of the temporal lobes, such as the hippocampal formation are reduced in AD, as compared to healthy subjects.
The role of white matter changes (WMH, leukoaraiosis) in the development of AD or as a diagnostic marker for AD is unclear. The degree of WMH has been shown to be strongly age dependent and there are contradictory data concerning its relation to cognitive decline. There is stronger agreement concerning the relationship between LA assessed with CT and cognitive functions than there is between WMH on MRI and cognitive functions.
Correlative studies with MRI, CT and SPECT or PET are few. Usually the sensitivity and specificity of diagnosing AD can be increased by combining two or more modalities. One other goal with this approach is to use one structural modality, such as MRI or CT as a template for functional images in order to obtain a higher accuracy in measurement of blood perfusion or glucose metabolism.     

Carotid atherosclerosis and cerebral white matter lesions in a population based magnetic resonance imaging study

Cerebral white matter lesions are frequently observed on magnetic resonance imaging of elderly, nondemented persons. There is evidence that white matter lesions are involved in the pathophysiology of cognitive decline and dementia. White matter lesions can be divided into those in the periventricular and those in the subcortical region. Pathological and epidemiological studies suggest that atherosclerosis is involved in the pathogenesis of these lesions. Our study reports on the association between atherosclerosis in the carotid arteries and white matter lesions in a population-based study among 1077 elderly subjects. We randomly sampled 1077 subjects aged between 60–90 years from two prospective population-based studies. All subjects underwent ultrasonography of the carotid artery. In addition, 1.5 T magnetic resonance imaging was performed; white matter lesions in the subcortical and periventricular regions were rated separately. With increasing number of plaques in the carotid artery the severity of periventricular white matter lesions increased (P _trend = 0.03), but not the severity of subcortical white matter lesions (P _trend = 0.19). In addition, an increase in intima media thickness was borderline significantly associated with an increased severity of periventricular white matter lesions (P _trend = 0.09), but not of subcortical white matter lesions (P _trend = 0.68). These findings suggest that partly dissimilar pathogenetic mechanisms are involved in the etiology of periventricular and subcortical white matter lesions. Received: 13 January 1999/Received in revised form: /15 November 1999/Accepted: 17 December 1999     

静息状态功能磁共振成像观察轻度阿尔茨海默病后扣带回功能连通性的变化

目的 利用静息状态功能磁共振成像(fMRI)研究阿尔茨海默病(AD)早期后扣带回相关的静息脑网络连通性是如何变化的.方法 运用fMRI研究了16例轻度AD患者和16名健康对照者在静息状态后扣带回的功能连通性.与后扣带回有功能连通性的脑区是通过检测低频波动信号的时程相关性获得的.应用通用的SPM2图像统计软件计算组间和组内连通性差异,激活区阈值设置:P<0.01(校正),像素范围>5.利用SPM2软件随机效应分析t检验(经校正P<0.01,t=2.47,像素范围>5),比较患者组和对照组连通性激活的脑区.结果 与后扣带回有功能连通性减弱的脑区包括前额叶中线区、楔前叶、双侧视皮质、双侧颞下回、左侧海马、右侧丘脑、右侧额叶背外侧区;偏左侧化的连通性增高的脑区包括前额叶中线区、左侧颞下回、左侧基底节区、双侧额叶背外侧区及左侧中央前区.结论 与后扣带回相关的静息状态脑网络连通性减低与AD早期情节记忆损害和高级视觉功能损害有关系,轻度AD保留着功能连接的重塑性以便维持脑功能.静息fMRI是一种探索AD脑功能机制的适宜方法.     

In vivo proton magnetic resonance spectroscopy of the temporal lobe in Alzheimer's disease

PURPOSE: Prior proton magnetic resonance spectroscopy (MRS) studies have consistently reported decreased brain n-acetyl aspartate (NAA) levels and increased myo-inositol (mI) levels in subjects with Alzheimer's disease (AD) relative to healthy comparison subjects. These studies have usually been conducted in small and homogeneous populations of patients with established Alzheimer's disease. Few studies have tested the usefulness of this finding in a general population seeking evaluation for memory loss and other cognitive declines. We designed a study to evaluate the significance of single-voxel proton MRS findings in these patients with memory loss and other cognitive declines. GENERAL METHOD: Thirty-five subjects with a primary complaint of memory loss and other cognitive declines were consecutively referred over a period of 13 months to a specialty clinic. Patients with a diagnosis of mild to moderate probable Alzheimer's disease (N = 22), non-Alzheimer's dementia (depression, multiinfarct dementia, Parkinson's Disease, Korsakoff's Psychosis, and bipolar disorder; N = 13), and healthy comparison subjects (N = 18) were examined with respect to possible differences in metabolites using proton MRS in a 3.4-ml anterior temporal lobe voxel. FINDINGS: The Alzheimer's disease group had 10.7% lower NAA/creatine (Cr) ratios relative to the healthy comparison group and 9.4% lower NAA/creatine relative to the non-Alzheimer's dementia group (15.0% lower NAA/creatine relative to the depression subgroup of the non-Alzheimer's dementia group). There were no significant differences in choline (Cho) or myo-inositol ratios among the groups. There were significant correlations between NAA/creatine ratios and mini-mental status exam (MMSE) scores in subjects with Alzheimer's disease (t = 2.41, p = 0.032) but not in subjects with non-Alzheimer's dementia or in its depression subgroup. CONCLUSIONS: This study found a reduction in the neuronal marker NAA in the anterior temporal lobe of patients diagnosed with probable Alzheimer's disease, using a short add-on proton MRS exam. This change was not observed in patients whose memory loss and other cognitive declines were not attributed to Alzheimer's disease, suggesting that it may aid in the diagnosis or detection of Alzheimer's disease.     

Magnetic resonance imaging, Down's syndrome and Alzheimer's disease: research and clinical implications

Background The diagnosis of Alzheimer's disease (AD) remains at times difficult to make using available neuropsychological measures. Neuro‐imaging is a relatively new form of detecting the changes associated with dementia. The present study investigated the role of magnetic resonance imaging (MRI) in diagnosing AD in adults with Down's syndrome (DS). Methods Subjects with DS and Alzheimer‐type dementia were matched to non‐demented controls with DS. Magnetic resonance imaging findings (i.e. volumetric and two‐dimensional scans) were compared between the two groups in order to show a relationship between the changes of AD and structural MRI abnormalities. Results Specific structural abnormalities which are seen in non‐intellectually disabled subjects with dementia are also found in individuals with both DS and AD. However, such findings cannot be used to diagnose clinical AD with good accuracy in adults with DS. A number of practical issues of patient compliance and over‐sedation are demonstrated by the findings. Conclusions Magnetic resonance imaging has an important but limited role to play in the management of AD in the population with DS. If intravenous sedation is used, medical support is essential to prevent a serious mishap.     

Diffuse cortical lesions with hemorrhage in cerebral Whipple's disease

A 30-year-old Chinese male with a history of diarrhea and arthralgia presented for evaluation of progressive dementia, epilepsy, and increased intracranial pressure. Imaging of the brain showed progressive cortical and subcortical lesions with hemorrhage involving the bilateral temporal and occipital lobes, the posterior parietal lobes, and the left frontal lobe. "Foamy" periodic acid-Schiff (PAS)-positive macrophages were demonstrated on brain biopsy. The patient showed clinical improvement following treatment with chloromycetin and sulfadiazine for 2 months. This constitutes the first reported case of cerebral Whipple's disease with diffuse cortical lesions with hemorrhage reported in a Chinese individual. Further, this case points out the significance of early recognition and treatment of cerebral Whipple's disease, especially in those cases with unusual manifestations.     

平山病患者的临床电生理及颈磁共振成像研究

目的 研究平山病(HD)患者的临床特征、肌电生理及颈磁共振成像(MRD特点.方法 观察15例HD患者的特殊临床表现.检测双侧上肢远端及下肢常规肌电图及周围神经传导速度.行颈部自然位、过屈位及过伸位MRI扫描,观察低位颈髓有无萎缩及颈椎曲线情况.结果 15例患者均为男性,青春期起病.病变均表现为上肢远端肌肉、骨间肌、鱼际肌萎缩和双手厥冷无力.肌电图检查示患者受累侧远端肌运动单位平均时限宽,多相波增多,波幅显著增高(巨大电位),主要位于C7、C8及T1节段.颈自然位MRI示9例患者低位颈髓萎缩,主要在C5、C6节段.所有患者过屈位时颈髓前移、变扁平,变扁节段以C6为主.结论 HD主要发生在青春期,以男性多见,临床表现和肌电图检查提示局限于下位颈髓的前角病变,颈部自然位和过屈位MRJ不同的特点可协助诊断.     

Magnetic resonance imaging for diagnosis of early Alzheimer's disease

A major challenge for neuroimaging is to contribute to the early diagnosis of Alzheimer's disease (AD). In particular, magnetic resonance imaging (MRI) allows detecting different types of structural and functional abnormalities at an early stage of the disease. Anatomical MRI is the most widely used technique and provides local and global measures of atrophy. The recent diagnostic criteria of “mild cognitive impairment due to AD” include hippocampal atrophy, which is considered a marker of neuronal injury. Advanced image analysis techniques generate automatic and reproducible measures both in the hippocampus and throughout the whole brain. Recent modalities such as diffusion-tensor imaging and resting-state functional MRI provide additional measures that could contribute to the early diagnosis but require further validation.     

阿尔茨海默病和血管性痴呆的颅脑核磁共振定量研究

目的测量阿尔茨海默病（AD）、血管性痴呆（VD）患者颅脑MRI片上的海马结构（HF）、胼胝体（CC）、侧脑室（LV）、外侧裂（SL）、白质疏松（LA）体积，建立判别函数，进行判别分析，提高区分AD组、VD组与老年健康对照组（NC）间的准确性。方法应用GE Signa 1．5T超导磁共振成像系统，对AD组、VD组、NC组各20例进行颅脑扫描，根据体视学的卡瓦列里原理，构建测试网格，对HF、CC、LV、SL、LA体积进行测量，建立判别函数，进行判别分析。结果AD组、VD组HF、CC体积均显著小于NC组，LV、SL、LA体积显著大于NC组；AD组的HF、LA体积均显著小于VD组。Fisher判别函数示判别总符合率为83.3％，AD组为95％，VD组为75％，NC组为80％。结论测量颅脑MRI的HF、CC、LV、SL、LA体积，建立判别函数，对AD、VD患者的临床诊断及鉴别诊断可能有一定的指导意义。     

Visual assessment of medial temporal lobe atrophy on magnetic resonance imaging: Interobserver reliability

We conducted an interobserver study to assess agreement on visual rating of medial temporal lobe atrophy on coronal T1-weighted MRI. A total of 100 studies of elderly individuals, using two different MRI techniques (spin echo and inversion recovery sequences), were analysed by four raters (three neurologists and one neuroradiologist) using a five-point rating scale. Complete agreement was found in 37% of the total sample. Interobserver agreement as expressed by kappa values was 0.44 (95% CIl0.34–0.54) and 0.51 (95% Cl=0.41–0.61) for the two techniques. After dichotomizing medial temporal lobe atrophy into present or absent, a post hoc analysis revealed higher complete agreeement (70%), with kappa values of 0.59 (95% Cl=0.51–0.67) and 0.62 (95% Cl=0.48–0.075), for the two techniques (all four raters). From this study we conclude that visual rating of medial temporal lobe atrophy on MRI in the coronal plane yields fair to good agreement among observers. We recommend this type of visual rating for use in clinical settings when a quick judgement on the presence of medial temporal lobe atrophy is needed.     

静息态功能磁共振成像观察阿尔茨海默病患者大脑自发活动特点

目的 运用静息态功能磁共振成像(fMRI)技术探测老年阿尔茨海默病(AD)患者大脑自发活动特点.方法 选择23例AD患者(AD组)和21名健康志愿者(NC组),分别接受神经心理学检查(MMSE、听觉词语学习测试)和静息态fMRI扫描,比较两组间神经心理评分和局部一致性(ReHo)的差异.结果 AD组(分)MMSE(20±4)、听觉词语学习测试即刻回忆(2.6±1.6)、延迟回忆(0.4±0.7)及再认成绩(5.8±3.7)均低于NC组(29±1、5.9±1.2、5.5±2.0、9.2±1.1,T=10.58、7.21、10.99、3.96,均P＜0.01);当设置单个体素统计阈值为P＜ 0.01、激活簇≥100体素时,与NC组比较,AD组在前额叶内侧面、后扣带回及楔前叶、右侧颞上回、两侧顶上小叶及顶下小叶等默认网络脑区ReHo值降低;在左侧壳核、丘脑的ReHo值增高.结论 AD患者存在大脑默认功能网络异常;而在壳核、丘脑的自发活动增强,可能是大脑皮质下结构对默认系统功能降低的代偿反应.     

MR灌注加权成像对脑胶质瘤病理分级的临床研究

目的 探讨磁共振(MR)灌注加权图像对脑胶质瘤病理分级的临床应用价值.方法 选择经病理证实的30例胶质瘤患者入组研究.分为高级和低级两组,其中低级胶质瘤14例(Ⅰ级1例,毛细胞型星形细胞瘤;Ⅱ级13例,星形细胞瘤11例包括1例术后复发,室管膜瘤1例,少突胶质细胞瘤1例);高级胶质瘤16例(Ⅲ级11例,均为间变性星形细胞瘤,包括1例为术后复发;Ⅳ级5例,胶质母细胞瘤4例,室管膜瘤1例).行MR灌注加权成像,测量肿瘤实质的局部相对脑血容量(rCBV)、相对平均通过时间(rMTT)、相对最大下降斜率(rMSD)值,进行统计学分析.结果 低级胶质瘤的rCBV、rMSD、rMTT值分别为1.99±1.00,1.83±0.78,1.10±0.08,高级胶质瘤的rCBV、rMSD、rMTT值分别为4.95±2.04.3.59±1.13.1.03±0.61.高级与低级胶质瘤的rCBV、rMSD值比较,差异均有统计学意义(P<0.05).以低级胶质瘤实质rCBV、rMSD值的上限2.99、2.61作为判断阈值,诊断正确率分别为83.3%、80%.结论 rCBV、rMSD值对脑胶质瘤分级的诊断有较高的准确性.     

脑梗死相关白质疏松患者磁共振波谱与认知功能关系的研究

目的研究脑梗死患者白质疏松的磁共振波谱表现特点,以及白质疏松的磁共振波谱与认知功能的关系,为血管性认知功能障碍的早期识别及防治提供依据。方法选择51例脑梗死伴白质疏松患者及21例非白质疏松者进行简易智能状态测验(MMSE)、画钟试验测试、Fuld物体记忆测验(FOM)、快速词汇测验(RVR)及WAIS数字广度测验;同时行头颅磁共振成像(MRI)及双侧额叶白质的磁共振波谱(MRS)检查,测定N-乙酰天门冬氨酸(NAA)、肌酸(Cr)及胆碱(Cho)的浓度。分析白质疏松的MRS表现特点及其与认知功能障碍的关系。结果重度脑白质疏松组Cho/Cr值明显高于无、轻及中度疏松组;Cho/Cr值与白质疏松程度呈正相关;左侧额叶白质NAA/Cr值与MMSE评分及画钟试验评分正相关;右侧Cho/Cr值与WAIS数字广度测验评分负相关。结论双侧额叶白质区MRS改变主要为Cho/Cr值升高,并且与白质疏松程度正相关。血管性认知障碍与双额叶白质区神经纤维损害不一定完全一致。     

6-Hydroxydopamine-induced lesions in a rat model of hemi-Parkinson's disease monitored by magnetic resonance imaging

Injection with 6-hydroxydopamine (6-OHDA) into the nigrostriatal pathway results in loss of nigrostriatal dopaminergic neurons, which has been used widely as an animal model of Parkinson's disease. In the present study, location and extent of lesions 1 day after 6-OHDA injections (2, 4, 8, or 16 microg as a free base) in the substantia nigra (SN) were evaluated in rats by T(2)-weighted magnetic resonance imaging (MRI). The changes in MRI were also compared to immunohistochemical and behavioral changes. Hyperintense area in MRI was found at the region corresponding to 6-OHDA injection in a dose-dependent manner and was accompanied by a loss of tyrosine hydroxylase (TH)-positive cells. The shape of hyperintense area in the SN appeared to be composed of two components (i.e., circular and longitudinal regions). Administration of a larger dose of 6-OHDA (8-16 microg) was accompanied by an increase in hyperintense area and loss of TH-positive cells beyond the SN. The hyperintense area was observed on the first and third days after 6-OHDA injection, but the size and intensity declined to near normal levels on the ninth day. Rotational behavior induced by methamphetamine reached maximal levels at 4 microg 6-OHDA, and the behavior was maintained with doses up to 16 microg of 6-OHDA. Intrastriatal injection with 6-OHDA was less effective. These results suggest that MRI provides highly valuable information for verifying the size and location of intended lesions as well as for determining the optimal dose of neurotoxins in individual animals.     

肥厚性硬脑膜炎12例临床表现和影像特征

目的　研究肥厚性硬脑膜炎(hypertrophiccranialpachymeningitis, HCP)的临床表现和磁共振成像(MRI)特征。方法　对12例肥厚性硬脑膜炎患者的临床和MRI资料进行回顾性分析。结果　多呈慢性起病,临床上以头痛(11例)和脑神经麻痹(9例)为主要表现,其中外展神经受损者7例,三叉神经4例,视神经、动眼神经、滑车神经、面神经各2例。MRI示受累硬脑膜最多见于鞍旁海绵窦区(7例),小脑幕(6例)次之,中颅窝底、大脑凸面各4例,累及大脑镰3例。同一病例可累及多个部位(弥漫型),本组弥漫型7例,局限型5例。增厚的硬脑膜厚度为0. 5 ~2. 0cm,形状多呈条带状或斑块状; T1WI呈与脑灰质相等或略低信号,T2WI呈低信号, 4例靠近脑实质面的硬膜呈明显高信号;增强后增厚的硬脑膜明显强化。5例伴邻近脑实质长T1 长T2 异常信号灶。复查时,病情改善者硬脑膜变薄,累及范围缩小,强化减轻,伴发的脑内异常信号影缩小或消失。结论　肥厚性硬脑膜炎的MRI表现较具特征性,结合临床资料可以做出较明确诊断。     

Striatal lesions in delusional parasitosis revealed by magnetic resonance imaging

Introduction

Delusional parasitosis (DP) is a syndrome characterized by the firm conviction that small living beings infest the skin. The etiology can be primary and secondary. Structural brain abnormalities in DP have only been reported in case reports often subcortical vascular encephalopathy and right-hemisphere strokes in the temporo-parietal cortex. Systematic brain imaging studies are lacking. We aimed to identify a brain region with structural lesions in patients with DP in order to better understand the pathophysiology of DP.

Methods

Nine consecutive patients with DP in a psychiatric outpatient department were assessed clinically and by means of cranial magnetic resonance imaging (MRI).

Results

Five of the nine cases were diagnosed as having DP as psychotic disorders due to a general medical condition while three had DP arising from pre-existing psychiatric illness and one suffered from a delusional disorder, somatic type (primary form). Four of the five DP cases secondary to a general medical condition (one case could not be analyzed) had striatal lesions predominantly in the putamen. Thalamic or cortical lesions were found in one case, respectively. In the primary DP case and all cases secondary to another psychiatric disorder basal ganglia and subcortical gray matter lesions were absent. In all medical (secondary) DP cases subcortical white matter lesions were found mainly in the centrum semiovale. Three of the five medical DP cases showed severe generalized brain atrophy which was absent in the primary DP case and in the cases secondary to other psychiatric disorders.

Discussion/conclusion

We present the findings of the first structural MRI study in DP. Our results suggest a possible relevance of structural lesions in the striatum, predominantly the putamen, in the medical (secondary) DP-subgroup. Our findings are in line with other studies demonstrating that the putamen, in addition to its role in motor regulation, represents a brain area that mediates visuo-tactile perception. Disturbed functioning of the putamen and associated brain areas of the somatic/dorsal striato–thalamo–cortical loop might therefore play an important role in the pathophysiology of DP, which is characterized by somatic delusions, tactile misperceptions and sometimes also visual hallucinations. The involvement of the striatum and the efficacy of antidopaminergic antipsychotics indicate dopaminergic dysfunction in DP. Evidence from DP in intoxication with substances influencing the dopamine transporter (DAT) (e.g. cocaine, methylphenidate, bupropion) further supports this observation. Further neuroimaging studies in larger samples are needed to expand our preliminary knowledge obtained from this case-series study.