未经治疗的抑郁症首次发病患者脑弥散张量成像的研究

目的 通过对未经治疗的抑郁症首次发病(以下简称首发)患者进行弥散张最成像(DTI)检查,探讨抑郁症患者脑门质的完整性及其与病程和抑郁严重程度的相关性.方法 对17名首发末服药抑郁症患者(以下简称患者组)和17名年龄、性别和文化程度相匹配的健康对照(以下简称对照组)进行全脑DTI扫描.以基于体素的分析比较两组受试者脑白质的分数各向异性(FA)的差异.提取差异有统计学意义的脑区的FA绝对值,将其与汉密尔顿抑郁量表(17项,HAMD)总分和患者病程进行相关分析.结果 患者组的双侧额中回、左侧扣带回和颞下回白质的FA值显著低于对照组(P＜0.01,cluster＞100).右侧额中回的FA值与病程呈显著负相关(r=-0.732,P=0.001).未发现各脑区的FA值与HAMD总分存在相关.结论脑白质完整性异常可能是抑郁症的生物学特征之一,抑郁症病程对脑白质的完整性有明显影响.     

老年抑郁症恢复期患者认知损害与全脑白质纤维完整性的相关性研究

目的 探讨恢复期老年抑郁症患者全脑白质纤维完整性是否受损,并进一步分析其与认知损害是否关联.方法 对16例恢复期老年抑郁症患者(患者组)和14名健康老年人(对照组)进行汉密尔顿抑郁量表(HAMD)、简易智力状态检查(MMSE)和神经心理学评估后,行全脑弥散张量成像扫描,用SPM2软件处理图像,采用基于体素的分析方法进行组间比较分数各向异性(FA)值.结果 (1)HAMD、MMSE评分和神经心理学测试:患者组HAMD和MMSE评分与正常对照组的差异无统计学意义(P>0.05),但在听觉言语测验[(5.9±2.6)分]、连线测验A[(146±127)s]和B[(264±196)s]成绩均差于正常对照组[分别为(9.3±1.6)分,(73±25)s和(121±35)s;P<0.01～0.05].(2)FA值:患者组低于对照组的脑区主要包括:右侧额上回、左侧额下回、左侧颞中回、右侧顶下回、右侧枕中回、左侧舌回、右侧壳核和右侧尾状核(未校正,P<0.001).(3)患者组右侧额上回FA值与连线B测验成绩呈显著负相关(r=-0.556,P=0.049).结论 恢复期老年抑郁症患者多部位脑白质纤维的完整性受损,这可能是该类患者认知损害的神经病理基础.     

抑郁症首次发病中年女性患者的弥散张量成像研究

目的 运用基于纤维束示踪的空间统计学方法(tract-based spatial statistics,TBSS)探索首次发病抑郁症中年女性患者脑白质微观结构的损害.方法 对20例首次发病抑郁症中年女性患者(患者组)和15名与患者组性别、年龄、受教育程度相匹配的健康志愿者(对照组)进行全脑弥散张量成像扫描.应用TBSS方法对患者组和对照组的部分各向异性(fractional anisotropy,FA)值进行组间比较.结果 与对照组相比,患者组左侧前额叶、左侧内囊、右侧楔前叶白质的FA值显著降低(P ＜0.005,簇＞40).结论 脑白质病变在抑郁症发病的早期即已存在,异常脑区涉及与认知和情感调节关系较密切的前额叶-子皮质神经环路和默认网络的纤维束.     

精神分裂症患者及其健康同胞的弥散张量成像研究

目的 探索精神分裂症患者及其健康同胞是否存在类似的脑白质完整性异常.方法 采用弥散张量成像技术扫描精神分裂症患者(患者组)、患者的健康同胞(同胞组)和健康对照(对照组)的全脑,用基于体素的分析方法比较3组的白质纤维分数各向异性(fractional anisotropy,FA)值.结果 在左侧前额叶和海马区,患者组(左侧前额叶:0.303±0.006,海马:0.310±0.O05)和同胞组(左侧前额叶:0.320±0.006,海马:0.318±0.006)的白质FA值显著小于对照组(左侧前额叶:0.338±0.007,海马:0.338±0.005),差异均有统计学意义(P＜0.05),患者组与同胞组的差异无统计学意义(P＞0.05);在左侧前扣带区,患者组白质FA值(0.391±0.006)显著小于同胞组(0.423±0.006)和对照组(0.412±0.007),差异有统计学意义(P＜0.05),同胞组的FA值大于对照组,但差异无统计学意义(P＞0.05).结论 精神分裂症患者及其健康同胞存在相似的脑白质完整性异常,左侧前额叶和海马白质FA值降低可能意味着精神分裂症的患病风险,左侧前扣带的白质FA值降低则可能是向该病转换的决定因素.     

轻度脑外伤患者弥散张量成像与认知功能

目的探讨轻度脑外伤(mild traumatic brain injury,m TBI)患者脑白质弥散张量成像(diffusion tensor imaging,DTI)的特点及其与认知功能的关系。方法对36例m TBI患者(患者组)36例健康受试者(对照组)进行全脑DTI扫描和认知功能测查,采用基于体素的全脑分析法比较患者组和对照组全脑白质各向异性(fractional anisotropy,FA)图像;采用t检验比较两组FA值的差异;提取患者组差异脑区FA值,与P300波幅、潜伏期,蒙特利尔认知评估量表(Montreal cognitive assessment,Mo CA)评分,汉密顿抑郁量表(Hamilton depression scale,HDRS)评分,汉密顿焦虑量表(Hamilton anxiey scale,HAMA)评分,年龄及受教育程度进行相关分析。结果与对照组比较,患者组FA降低的脑区分布在右额内侧回,双侧中央后回、左楔前叶,左后扣带回和右颞上回(P<0.01,FDR校正);未发现有FA增高的脑区。Pearson相关分析未发现各异常脑区FA值与患者各临床特征因子存在相关(P>0.05)。结论 m TBI患者存在认知功能损害和多个脑区白质微细结构的损害。     

弥散张量成像对阿尔茨海默病脑白质改变的评价

目的分析阿尔茨海默病(Alzheimer's disease,AD)脑白质结构改变及与认知功能的关系。方法对37例AD组和32例对照组行简易精神状态量表(mini-mental State examinationn,MMSE)评估和DTI扫描。采用基于全脑体素分析法对两组全脑白质各向异性(fractional anisotropy,FA)图进行比较,采用t检验分析FA值差异,并评估AD组MMSE评分与FA值相关性。结果 AD患者出现FA值下降区域广泛分布在右侧额叶、颞叶、枕叶、丘脑及双侧扣带回、胼胝体、楔前叶、顶叶下回、顶下小叶、缘上回及海马旁回(其中P0.001,未经校正的P值);当使用经FWE校正的P0.05后,AD患者右侧扣带回、左侧胼胝体、颞叶下回及双侧顶叶下回、额叶下回、楔前叶区域FA值较对照组显著下降。AD患者FA值下降与MMSE量表评分呈正相关,(P0.001,未经校正)。结论 AD患者存在特定脑区白质结构改变,并与认知功能损害程度呈正相关。     

女性重性抑郁障碍患者体质量指数与脑白质完整性异常的相关性研究

目的:探讨女性重性抑郁障碍患者体质量指数(BMI)与脑白质完整性异常的相关性。方法:收集自2017年10月至2018年10月门诊就诊的女性重性抑郁障碍患者58例(患者组)及年龄、BMI、受教育程度相匹配的女性健康对照者57名(对照组)进行核磁共振扫描,完成临床相关量表的评定。比较两组磁共振弥散张量成像(DTI)数据,分别对两组的DTI图像与BMI进行相关性分析,并对各向异性值(FA值)进行提值计算。结果:患者组与对照组DTI比较存在两簇差异脑区,分别位于胼胝体压部及体部、右下额枕束,且患者组的FA值低于对照组。患者组BMI与右侧外囊的FA值呈正相关(r=0.531,P0.01);对照组BMI与胼胝体体部、膝部及压部的FA值呈负相关(r=-0.497,P0.01)。结论:女性重性抑郁障碍患者胼胝体压部、体部及右下额枕束白质完整性降低,肥胖所致的胼胝体完整性降低可能是重性抑郁障碍患者患病的相关因素。     

精神分裂症患者全脑白质纤维弥散张量成像的初步研究

目的运用能够提示白质纤维(white matter,WM)完整性的弥散张量成像(diffusion tensor imaging,DTI)技术,探讨精神分裂症患者全脑白质纤维是否受到损害。方法对21例精神分裂症患者(患者组)和21名健康人(对照组)进行全脑DTI扫描,用SPM2(Statistical Parametric Maps,SPM)软件对图像进行处理,采用以像素为基础的分析方法(voxel-based analysis,VBA)对两组的分数各向异性(fractional anisotropy,FA)值进行组间比较。结果患者组下列脑区的FA值显著低于对照组(P<0·001):左侧额眶区和右侧额中回的白质、双侧颞下回白质、双侧顶叶内侧白质、右侧前扣带、双侧海马、双侧大脑脚、双侧岛叶、右侧放射冠和右侧小脑上脚。结论精神分裂症多个部位脑白质纤维的完整性受到破坏。     

磁共振扩散张量成像对阻塞性睡眠呼吸暂停低通气综合征患者脑白质损害的评价

目的运用磁共振扩散张量成像(DTI)序列扫描,并用基于体素的分析(VBA)方法对阻塞性睡眠呼吸暂停低通气综合征(OSAHS)患者全脑不同脑区的脑白质神经纤维束的完整性进行检测,探讨DTI对OSAHS患者脑白质损害的评价。方法收集OSAHS患者26例,以及与OSAHS组年龄、性别相匹配的正常志愿者22例,两组均为男性,行头颅DTI扫描。用DTI Studio软件和基于Matlab平台的SPM8和REST软件对所采集的图像进行后处理,并通过VBA方法分析。观察OSAHS组各向异性分数(FA)值相对于正常对照组的变化,得出两组差异有统计学意义的脑区位置以及簇体积。结果与对照组相比较,OSAHS组部分脑区FA值显著减低(P<0.001并经过alphasim校正),FA值下降的区域主要位于额叶及顶叶皮质、前、后扣带回、脑干、腹外侧核、胼胝体、背侧丘脑及杏仁核等。结论 OSAHS患者多个脑区FA值均较正常志愿者明显减低,证实OSAHS患者脑白质存在着广泛的损伤。运用VBA方法对DTI分析可以评价OSAHS患者的脑白质损伤。     

CADASIL脑弥散张量成像特点及与临床的关系

目的 分析常染色体显性遗传性脑动脉病伴皮层下梗死和白质脑病(cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy,CADASIL)患者的弥散张量成像特点及与临床的关系.方法 患者和同龄健康志愿者各14例,进行头颅MRI常规扫描和弥散张量成像扫描,测量两组受试者各脑叶、内囊后肢、外囊以及胼胝体的部分各向异性(fractional anisotropy,FA)值及总和,比较两组问FA值的差异.对患者的认知功能和卒中后神经功能状态分别进行MMSE和NIHSS评分.校正年龄影响,分析患者各个脑白质区域FA值及总和与MMSE分值、NIHSS评分的相关关系.结果 患者组各脑区的FA值均显著低于对照组.FA值总和、右额叶、右颞叶、左顶叶、左枕叶、双侧内囊后肢以及外囊白质的FA值和MMSE分值存在相关性(P＜0.05).FA值总和及各脑区FA值与NIHSS评分无相关性.结论 CADASIL患者不同脑白质区域的FA值显著下降,部分区域的白质损害与患者的认知功能减退有关.     

抑郁症患者脑白质变化初步研究

目的：利用能够提示脑白质纤维完整性的磁共振弥散张量成像（DTI）探讨首发和复发重性抑郁症患者脑白质纤维的变化及其差异。方法：20例重性抑郁症患者（首发9例，复发11例）和20名正常对照者均经常规磁共振成像（MRI）平扫，未发现异常者继续进行DTI和结构MRI（3D）扫描，基于像素的全脑分析技术对DTI数据进行分析。结果：与对照组相比较，抑郁症组白质纤维结构在双侧额中回、右顶下小叶及双侧脑岛等区域白质的各向异性值（FA）显著降低（各脑区P均〈0.001，cluster〉30像素）;与首发抑郁症患者相比较，复发抑郁症患者右侧额上回、右顶叶、中央前回、中央后回及右顶下小叶等区域FA值降低更为显著（各脑区P均〈0.001，cluster〉10像素）。结论：重性抑郁症患者存在脑白质异常，抑郁反复发作会导致脑白质损害进一步加重。     

State-dependent microstructural white matter changes in bipolar I depression

Abnormalities in fronto-limbic-striatal white matter (WM) have been reported in bipolar disorder (BD), but results have been inconsistent across studies. Furthermore, there have been no detailed investigations as to whether acute mood states contribute to microstructural changes in WM tracts. In order to compare fiber density and structural integrity within WM tracts between BD depression and remission, whole-brain fractional anisotropy (FA) and mean diffusivity (MD) were assessed in 37 bipolar I disorder (BD-I) patients (16 depressed and 21 remitted), and 26 healthy individuals with diffusion tensor imaging. Significantly decreased FA and increased MD in bilateral prefronto-limbic-striatal white matter and right inferior fronto-occipital, superior and inferior longitudinal fasciculi were shown in all BD-I patients versus controls, as well as in depressed BD-I patients compared to both controls and remitted BD-I patients. Depressed BD-I patients also exhibited increased FA in the ventromedial prefrontal cortex. Remitted BD-I patients did not differ from controls in FA or MD. These findings suggest that BD-I depression may be associated with acute microstructural WM changes.     

Voxel-based analyses of gray/white matter volume and diffusion tensor data in major depression

The purpose of this study is to use voxel-based analysis to simultaneously elucidate regional changes in gray/white matter volume, mean diffusivity (MD), and fractional anisotropy (FA) in patients with unipolar major depressive disorder. We studied 21 right-handed patients and 42 age- and gender-matched right-handed normal subjects. Local areas showing significant gray matter volume reduction in depressive patients compared with controls were observed in the right parahippocampal gyrus, hippocampus, bilateral middle frontal gyri, bilateral anterior cingulate cortices, left parietal and occipital lobes, and right superior temporal gyrus. Local areas showing an increase of MD in depressive patients were observed in the bilateral parahippocampal gyri, hippocampus, pons, cerebellum, left frontal and temporal lobes, and right frontal lobe. There was no significant difference between the two groups for FA and white matter volume in the entire brain. Although there was no local area where brain volume and MD were significantly correlated with disease severity, FA tended to correlate negatively with total days depressed in the right anterior cingulate and the left frontal white matter. These results suggest that the frontolimbic neural circuit might play an important role in the neuropathology of patients with major depressive disorder.     

Altered white matter integrity in temporal lobe epilepsy: Association with cognitive and clinical profiles

Purpose: Diffusion tensor imaging (DTI) studies have reported substantial white matter abnormalities in patients with temporal lobe epilepsy (TLE). However, limited data exist regarding the extent of white matter tract abnormalities, cognitive effects of these abnormalities, and relationship to clinical factors. The current study examined these issues in subjects with chronic TLE. Methods: DTI data were obtained in 12 TLE subjects and 10 age‐matched healthy controls. Voxel‐wise statistical analysis of fractional anisotropy (FA) was carried out using tract‐based spatial statistics (TBSS). White matter integrity was correlated with cognitive performance and epilepsy‐related clinical parameters. Results: Subjects with TLE, as compared to healthy controls, demonstrated four clusters of reduced FA, in anterior temporal lobe, mesial temporal lobe, and cerebellum ipsilateral, as well as frontoparietal lobe contralateral to the side of seizure onset. Mean FA was positively correlated with delayed memory, in anterior temporal lobe; and immediate memory, in mesial temporal lobe. Lower FA values in the posterior region of corpus callosum were related to earlier age of seizure onset. Conclusion: TLE is associated with widespread disturbances in white matter tracts and these changes have important cognitive and clinical consequences.     

Microstructural white matter changes in euthymic bipolar patients: a whole-brain diffusion tensor imaging study

Objectives:  Brain structures of a distributed ventral-limbic and dorsal brain network have been associated with altered mood states and emotion regulation in affective disorders. So far, diffusion tensor imaging studies in bipolar patients have focused on frontal/prefrontal brain regions and found alterations in white matter integrity in manic, depressed, and euthymic bipolar patients, observed as changes in fractional anisotropy and mean diffusivity. To extend previous findings, we investigated whole-brain modifications in white matter integrity in euthymic bipolar patients with minimal manic and depressive symptoms.
Methods:  Twenty-two patients with a DSM-IV-TR diagnosis of bipolar I and II disorder in remission, with no lifetime or present comorbidities of substance abuse, and 21 sex- and age-matched healthy controls underwent diffusion tensor imaging with diffusion gradients applied along 41 directions. Fractional anisotropy and mean diffusivity group differences were explored using two voxel-based, whole-brain analyses that differ in their normalization approaches.
Results:  Fractional anisotropy was significantly increased in bipolar patients relative to healthy controls in medial frontal, precentral, inferior parietal, and occipital white matter. No group differences in mean diffusivity were found.
Conclusions:  The result of increased fractional anisotropy in euthymic bipolar patients in the present study suggests increased directional coherence of white matter fibers in bipolar patients during remission.     

White matter abnormalities observed in bipolar disorder: a diffusion tensor imaging study

OBJECTIVES: An increased incidence in white matter abnormalities is among the most frequently reported brain change in patients with bipolar disorder. The objective of the present study was to examine white matter tract integrity, using diffusion tensor imaging (DTI), in bipolar patients and healthy comparison subjects. METHODS: Eleven DSM-IV bipolar I patients and 10 healthy age- and sex-matched controls were studied. DTI data were acquired on a 1.5 Tesla scanner. Fractional anisotropy (FA) and diffusivity (trace) were determined from axial images using region of interest (ROI) analyses. The ROIs were manually placed in the midline and forward projecting arms of the genu (anterior) and the midline of the splenium (posterior) of the corpus callosum. RESULTS: Bipolar patients had significantly higher FA in the midline of the genu compared with healthy controls. Regional white matter differences were also observed, with significantly lower FA in the genu than forward projecting regions in both groups and lower FA in the genu than the splenium in controls. CONCLUSIONS: Diffusion tensor imaging revealed significant microstructural differences in the genu, as measured by elevated FA in bipolar patients compared with healthy controls. These preliminary findings further support the hypothesis that anomalous frontal brain mechanisms may be associated with bipolar disorder.     

Frontal white matter integrity is related to psychomotor retardation in major depression

Altered frontal white matter integrity has been reported in major depression. Still, the behavioral correlates of these alterations are not established. In healthy subjects, motor activity correlated with white matter integrity in the motor system. To explore the relation of white matter integrity and motor activity in major depressive disorder, we investigated 21 medicated patients with major depressive disorder and 21 matched controls using diffusion tensor imaging and wrist actigraphy at the same day. Patients had lower activity levels (AL) compared with controls. Fractional anisotropy (FA) differed between groups in frontal white matter regions and the posterior cingulum. AL was linearly associated with white matter integrity in two clusters within the motor system. Controls had an exclusive positive association of FA and AL in white matter underneath the right dorsal premotor cortex. Only patients had a positive association within the posterior cingulum. Furthermore, patients had negative associations of FA and AL underneath the left primary motor cortex and within the left parahippocampal gyrus white matter. These differences in the associations between structure and behavior may contribute to well-known impaired motor planning or gait disturbances in major depressive disorder. Therefore, signs of psychomotor slowing in major depressive disorder may be linked to changes of the white matter integrity of the motor system.     

White matter microstructure alterations in bipolar disorder

Genetic, neuropathological and magnetic resonance imaging findings support the presence of diffuse white matter cytoarchitectural disruption in bipolar disorder. In this study, diffusion-weighted imaging (DWI) was applied to study cortical white matter microstructure organisation in 24 patients with DSM-IV bipolar disorder and 35 matched normal controls. DWI images were obtained using a 1.5 Tesla scanner and apparent diffusion coefficient (ADC) values were determined over regions of interest placed, bilaterally, in the frontal, temporal, parietal, and occipital white matter. Significantly increased ADC values were found in bipolar patients with respect to normal controls in the right temporal lobe, left parietal lobe and bilateral occipital lobes. ADC values did not associate significantly with age or with clinical variables (p>0.05). Diffuse cortical white matter alterations on DWI in bipolar disorder denote widespread disruption of white matter integrity and may be due to altered myelination and/or axonal integrity.     

MRI study of white matter diffusion anisotropy in schizophrenia

Diffusion tensor imaging (DTI) can provide information about brain white matter integrity. The results of DTI studies in schizophrenia are somewhat variable and could benefit from standardized image processing methods. Fourteen patients with schizophrenia or schizoaffective disorder and 14 healthy volunteers underwent DTI. Scans were analyzed using a rigorous voxelwise approach. The key dependent variable, fractional anisotropy, was lower for patients in the corpus callosum, left superior temporal gyrus, parahippocampal gyri, middle temporal gyri, inferior parietal gyri, medial occipital lobe, and the deep frontal perigenual region. Regions showing reduced white matter fractional anisotropy are known to be abnormal in schizophrenia. The voxelwise method used in the current study can provide the basis for hypothesis-driven research.     

高功能孤独症患儿全脑白质纤维的弥散张量成像研究

目的 分析高功能孤独症患儿的全脑白质纤维的完整性.方法 对18例高功能孤独症患儿(病例组)以及10名年龄、性别、智商与病例组相匹配的健康儿童(对照组)进行全脑弥散张量成像(DTI)测量;应用基于体素的分析方法,比较两组全脑各向异性分数(FA)的差异.使用Spearman相关分析,分析病例组各感兴趣区FA值与儿章期孤独症评定表(CARS)总分及各项目之间的关系.结果 与对照组相比,病例组右侧额下回、左侧额中回及右侧颞下回邻近白质的FA值低(分别为0.67±0.10、0.57±0.09、0.50 ±0.12),左顶上小叶邻近白质的FA值高(0.55±0.15;P<0.001).病例组左额中回邻近白质的FA值与CARS中的与非生命物体的关系的得分呈负相关(r=-0.63,P=0.005).结论 高功能孤独症患儿多个部位的脑白质纤维的完整性受到破坏.