抑郁症患者弥散张量成像与认知功能的关系

目的:探讨抑郁症患者全脑白质纤维受损状况及其与认知功能的关系.方法:对 24 例抑郁症患者及 30 名健康对照者进行临床测评、常规磁共振成像(MRI)、弥散张量成像(DTI)及神经心理学检查.结果:抑郁症组在左额中回、左额上回、右额内侧回、左楔前叶、左颞上回、右扣带回等区域各向异性(FA)值较对照组显著下降(P＜0.001).抑郁症组威斯康星卡片分类测验(WCST)的分类数、总错误率明显高于对照组(P＜0.01 或 P＜0.05).两组持续注意操作测试(CPT)差异无显著性;抑郁症组 CPT 与 WCST 部分结果均呈负相关(P均＞0.05).结论:DTI 与 WCST 结果的相互印证反映重性抑郁症患者可能存在白质区域神经功能的异常,DTI 技术有助于发现影响认知改变的脑微细结构和功能的异常.     

胶质瘤磁共振波谱研究进展

医学磁共振应用技术包括磁共振成像(MRI)和功能磁共振(functional MRI，fMRI)，后者包括磁共振波谱(magnetic resonance spectroscopy，MRS)、弥散加权成像(diffusion weighted imaging，DWI)、灌注加权成像(perfusion weighted imaging，PWI)和皮层激发功能定位成像等。胶质瘤是一类起源于神经上皮组织的肿瘤，在颅内各类型肿瘤中发病率为第一位。目前还没有一种临床和组织学标记物能评价其病理分     

抑郁症患者眶额叶皮层功能连接偏离的研究

目的 通过功能磁共振成像技术,研究抑郁症患者和健康对照组在情感处理时眶额叶皮层的功能连接偏离,为抑郁症的早期诊断和疗效评估提供影像学依据.方法 对25例重度抑郁症患者和15名健康对照组在执行面貌一致性任务时进行功能性磁共振成像.结果 和健康对照组相比重度抑郁症患者的背侧前扣带回皮层、楔前叶、小脑与眶额叶的活动连接减少;抑郁症患者的眶额叶皮层和背外侧前额叶皮层、右额叶岛盖部、左运动区之间的功能连接比健康对照组有所增加.结论 眶额叶皮层在抑郁症的病理生理学机制中发挥着关键作用.眶额叶皮层连接的失衡似乎代表加工偏离的神经机制.从神经生物学的角度来看,楔前叶和扣带回的连接解离活动与眶额叶皮层的自我架构规则的问题相关,而背外侧前额叶皮层到眶额叶的连接增加可能代表更高消极刺激的神经反应.     

高场强MRI弥散加权成像在超急性期脑梗死诊断中应用价值

目的探讨采用高场强MRI弥散加权成像对超急性期脑梗死患者行临床诊断的效果及其应用价值。方法回顾性分析我院脑内科2011-12-2014-01收治的超急性期脑梗死患者临床资料,均采用常规核磁共振(MRI)及高场强MRI弥散加权成像(DWI)进行检测,分析不同时期高场强MRI弥散加权成像诊断结果。结果脑梗死发病的超急性期及急性期,高场强MRI弥散加权成像方法检测时病灶的显示率都为100.0%,T_2加权像(T_2WI)时脑梗死患者的病灶显示率分别为28.57%(6/21)、61.76%(21/34)、100.0%(29/29)。结论采用高场强MRI弥散加权成像对超急性期脑梗死患者的诊断具有十分重要的临床意义,其诊断结果较常规核磁共振成像序列准确,提高了临床确诊率,值得临床推广使用。     

抑郁症功能磁共振成像的研究进展

目前,通过磁共振成像(magnetic resonance imaging,MRI)、正电子发射断层扫描术(positron emission tomography,PET)、功能磁共振成像(functional MRI,fMRI)等手段,已经发现抑郁症患者的脑神经存在着特定区域的结构和功能异常.     

磁共振弥散成像诊断急性缺血性脑血管病的观察

急性脑血管病早期正确的诊断对制定治疗方案和对改善患者的预后有十分重要的意义。近年来，随着神经影像技术的发展，MRI弥散成像(DWI)，使急性缺血性脑血管病的早期快速、准确诊断成为可能。现将我院子2003—02～2003—12收治的16例急性缺血性脑血管病患者的磁共振弥散成像结果报道如下。     

糖尿病中枢神经病变MRI影像研究进展

正糖尿病作为全身性疾病,其所导致的神经病变可以累及从中枢神经至神经肌接头的任何部位,包括糖尿病中枢神经病变(DCN)(大脑、小脑、脑干、脊髓及在其中上行、下行感觉及运动有髓鞘神经纤维)和糖尿病周围神经病变(DPN)[1]。DPN的相关研究甚多,但DCN却于近年才逐渐进入大家的视野。MRI在DCN方面的应用主要包括CNS功能区域体积计算、弥散张量成像(DTI)、MRI波谱成像(MRS)及血氧水平依     

带状灰质异位的磁共振弥散张量白质束成像研究

目的采用磁共振弥散张量白质束成像技术,观察带状灰质异位脑白质异常分布情况,探讨异位灰质的神经病理机制以及弥散张量白质束成像技术的应用价值。方法采用磁共振弥散张量白质束成像技术,对1例癫痫症状的带状灰质异位患者进行白质束描绘,观察其不同灰、白质的分布情况,并和1例正常人进行对比研究。结果弥散张量白质束成像技术很好地描绘了白质束结构。整体观察发现带状灰质异位患者脑白质整体结构紊乱,与正常人相比其联络弓状纤维稀疏、大部缺失,胼胝体纤维稀疏不整;局部分析发现内层灰质为主要的白质纤维发出处,而外层灰质仅发出细碎短小的纤维。结论对于带状灰质异位,异位的内层灰质不仅具有神经生理功能,并且可能起着主要作用,外层"正常"的灰质由于脑结构紊乱而丧失主要功能地位;灰质结构的紊乱导致白质纤维结构的缺失;弥散张量白质束成像技术可以很好地应用于带状灰质异位的神经机制研究。     

首次发病未用药老年抑郁症患者脑白质完整性的弥散张量成像研究

目的 使用弥散张量成像探讨首次发病未用药老年抑郁症患者的脑白质完整性.方法 15例首次发病未用药的老年抑郁症患者和15例正常对照组接受脑弥散张量成像扫描,用基于体素的分析方法对脑内所有体素的各向异性分数(FA)逐一进行组间比较.结果 与正常对照组相比,首次发病未用药老年抑郁症患者左侧前扣带(丛集体积=106体素,t=3.21)、右侧前扣带(丛集体积=60体素,t=2.71)、右侧膝下扣带(丛集体积=63体素,t=3.37)、左侧脑干(丛集体积=62体素,t=3.25)白质FA值显著降低(检验水准为未校正的单侧P＜0.01,体素集阈值＞50体素).结论 老年抑郁症发病早期存在双侧前扣带及右侧膝下扣带白质完整性下降,经由该脑区的神经通路损害可能与老年抑郁症的病理机制有关.     

MR弥散加权成像对超急性期脑梗死的诊断价值探讨

目的探讨MR弥散加权成像对超急性期脑梗死的诊断价值。方法回顾性分析我院脑内科2010-02—2014-02收治的96例超急性期脑梗死患者临床资料,均采用常规的磁共振(MRI)及MR弥散加权成像进行检测,分析疾病的不同时期低场强MR弥散加权成像诊断结果。结果在脑梗死发病的超急性期以及急性期,MR弥散加权成像对病灶的显示率为100.0%,T2加权像(T2WI)对脑梗死病灶显示率分别为32.00%(8/25)、57.89%(22/38)、100.00%(33/33)。结论采用MR弥散加权成像对超急性期脑梗死患者的诊断具有十分重要的临床意义,其诊断结果较MRI准确,值得推广使用。     

抑郁症患者静息状态的功能磁共振成像研究

目的 了解在静息状态下抑郁症患者脑区的局部一致性特点.方法 采用功能磁共振成像(fMRI)技术,检测静息状态下27例抑郁症患者(患者组)和性别、年龄、受教育程度均与患者相匹配的27名正常人(对照组)的脑功能活动,并对两组进行比较.利用局部一致性方法 分析fMRI数据,用SPM2软件进行配对t检验(P＜0.005).结果 与对照组相比,患者组双侧额中回、右额下回、右颞上回、左前扣带回、右后扣带回、右岛叶、双侧豆状核、双侧屏状核、左尾状核局部一致性显著增高(P＜0.005,未校正,体素值＞10);未显示脑区有明显的局部一致性减低.结论 抑郁症患者神经环路脑区局部在静息状态下具有很高的一致性,其局部一致性的增高可能参与了抑郁症的代偿机制.     

Neuroimaging predictors of onset and course of depression in childhood and adolescence: A systematic review of longitudinal studies

Major depressive disorder (MDD) often emerges during adolescence with detrimental effects on development as well as lifetime consequences. Identifying neurobiological markers that are associated with the onset or course of this disorder in childhood and adolescence is important for early recognition and intervention and, potentially, for the prevention of illness onset. In this systematic review, 68 longitudinal neuroimaging studies, from 34 unique samples, that examined the association of neuroimaging markers with onset or changes in paediatric depression published up to 1 February 2019 were examined. These studies employed different imaging modalities at baseline; structural magnetic resonance imaging (MRI), diffusion tensor imaging (DTI), functional MRI (fMRI) or electroencephalography (EEG). Most consistent evidence across studies was found for blunted reward-related (striatal) activity (fMRI and EEG) as a potential biological marker for both MDD onset and course. With regard to structural brain measures, the results were highly inconsistent, likely caused by insufficient power to detect complex mediating effects of genetic and environmental factors in small sample sizes. Overall, there were a limited number of samples, and confounding factors such as sex and pubertal development were often not considered, whereas these factors are likely to be relevant especially in this age range.     

Current progress in neuroimaging research for the treatment of major depression with electroconvulsive therapy

Electroconvulsive therapy (ECT) uses a certain amount of electric current to pass through the head of the patient, causing convulsions throughout the body, to relieve the symptoms of the disease and achieve the purpose of treatment. ECT can effectively improve the clinical symptoms of patients with major depression, but its therapeutic mechanism is still unclear. With the rapid development of neuroimaging technology, it is necessary to explore the neurobiological mechanism of major depression from the aspects of brain structure, brain function and brain metabolism, and to find that ECT can improve the brain function, metabolism and even brain structure of patients to a certain extent. Currently, an increasing number of neuroimaging studies adopt various neuroimaging techniques including functional magnetic resonance imaging (MRI), positron emission tomography, magnetic resonance spectroscopy, structural MRI, and diffusion tensor imaging to reveal the neural effects of ECT. This article reviews the recent progress in neuroimaging research on ECT for major depression. The results suggest that the neurobiological mechanism of ECT may be to modulate the functional activity and connectivity or neural structural plasticity in specific brain regions to the normal level, to achieve the therapeutic effect.     

Functional MRI correlates of visuospatial planning in out-patient depression and anxiety

van Tol MJ, van der Wee NJA, Demenescu LR, Nielen MMA, Aleman A, Renken R, van Buchem MA, Zitman FG, Veltman DJ. Functional MRI correlates of visuospatial planning in out‐patient depression and anxiety. Objective: Major depressive disorder (MDD) has been associated with executive dysfunction and related abnormal prefrontal activity, whereas the status of executive function (EF) in frequently co‐occurring anxiety disorders and in comorbid depression–anxiety is unclear. We aimed to study functional MRI correlates of (visuospatial) planning in MDD and anxiety disorders and to test for the effects of their comorbidity. Method: Functional MRI was employed during performance of a parametric Tower of London task in out‐patients with MDD (n = 65), MDD with comorbid anxiety (n = 82) or anxiety disorders without MDD (n = 64), and controls (n = 63). Results: Moderately/severely depressed patients with MDD showed increased left dorsolateral prefrontal activity as a function of task load, together with subtle slowing during task execution. In mildly depressed and remitted MDD patients, in anxiety patients, and in patients with comorbid depression–anxiety, task performance was normal and no activation differences were observed. Medication use and regional brain volume were not associated with altered visuospatial planning. Conclusion: Prefrontal hyperactivation during high planning demands is not a trait characteristic, but a state characteristic of MDD without comorbid anxiety, occurring independent of SSRI use. Disturbances in planning or the related activation are probably not a feature of anxiety disorders with or without comorbid MDD, supporting the current distinction between anxiety disorders and depression.     

Concurrent alterations of white matter microstructure and functional activities in medication-free major depressive disorder

Although numerous studies have revealed the structural and functional alterations in major depressive disorder (MDD) using unimodal diffusion magnetic resonance imaging (MRI) or functional MRI, however, the potential associations between changed microstructure and corresponding functional activities in the MDD has been largely uninvestigated. Herein, 27 medication-free MDD patients and 54 gender-, age-, and educational level-matched healthy controls (HC) were used to investigate the concurrent alterations of white matter microstructure and functional activities using tract-based spatial statistics (TBSS) analyses, fractional amplitude of low-frequency fluctuation (fALFF), and degree centrality (DC). The TBSS analyses revealed significantly decreased fractional anisotropy (FA) in the superior longitudinal fasciculus (SLF I) in the MDD patients compared to HC. Correlation analyses showed that decreased FA in the SLF I was significantly correlated with fALFF in left pre/postcentral gyrus and binary, weighted DC in right posterior cerebellum. Moreover, the fALFF in left pre/postcentral gyrus significantly reduced in MDD patients while binary and weighted DC in right posterior cerebellum significantly increased in MDD patients. Our results revealed concurrent structural and functional changes in MDD patients suggesting that the underlying structural disruptions are an important indicator of functional abnormalities.

     

术中1.5T核磁共振外科治疗难治性癫癎

目的探讨应用术中1.5T核磁共振(MRI)治疗难治性癫癎的手术效果。方法手术治疗难治性癫癎15例,利用术中1.5T核磁共振,术前常规行T1、T2及T1加强,及弥散张量成像,术中切除(切开)后行T1、T2及T1加强及弥散张量成像检查,以确定切除范围及功能区定位,其中5例术中MR检查后扩大切除。结果左侧枕叶局灶性皮质发育异常2例,左侧颞叶海绵状血管瘤4例,左侧颞叶海马硬化1例,右侧额叶胚胎发育不良性神经上皮肿瘤1例,右侧中央前回局灶性皮质发育不良1例,右侧颞叶海马硬化1例,右侧颞叶海绵状血管瘤1例,右侧颞叶胶质瘤1级1例,右侧中央后回海绵状血管瘤1例,胼胝体切开2例,engle分级:Ⅰ级11例,Ⅱ级4例。结论术中1.5T核磁共振对切除(切开)病灶及功能保护有指导意义。     

青壮年重症抑郁障碍的磁化传递成像研究

目的探讨青壮年重症抑郁障碍患者磁化传递率(MTR)值的改变及其与病程的相关性。方法根据美国精神障碍诊断与统计手册,选择临床晤谈诊断明确并且17项汉密尔顿抑郁量表评分≥18分的30例重症抑郁障碍患者,以及按照年龄、性别、利手性、受教育程度相匹配原则征集的30例正常对照者。采用3.0T MRI扫描仪采集磁化传递成像数据,统计参数图软件对所得MTR参数图进行标准化和平滑等预处理,再行基于体素的分析。MTR值的组间比较行双样本t检验,与病程的相关性分析采用Pearson相关分析。结果在统计参数图中,以团簇水平P<0.05作为统计显著性阈值。与正常对照组相比,重症抑郁障碍组患者未发现MTR值差异有统计学意义的脑区;相关分析显示,其在左侧前额叶、顶叶、颞叶部分区域,以及双侧前扣带回等脑区与病程呈显著负相关。进一步亚组分析显示,长病程(>60周)重症抑郁障碍患者MTR值在左侧额中回、双侧中扣带回、右侧小脑前叶低于与之相匹配的正常对照者;而短病程(≤60周)患者,MTR值则在左侧额中回、颞枕交界区、双侧前扣带回及邻近白质较正常对照者升高。结论不同病程重症抑郁障碍患者脑MTR值呈现不同改变模式,提示对重症抑郁障碍患者长期纵向随访的必要性,尤其是长期抗抑郁治疗对脑结构及功能的影响应作为重点研究课题。     

Homocysteine levels, MTHFR C677T genotype, and MRI Hyperintensities in late-onset major depressive disorder.

OBJECTIVE: Epidemiological studies suggest that elevated plasma homocysteine is associated with an increased risk of depression and cerebrovascular disease. There are no published reports of homocysteine levels and methylenetetrahydrofolate reductase (MTHFR) C677T genotype in clinical samples of patients with late-onset major depressive disorder (MDD). The purpose of this study was to examine the association of homocysteine levels or MTHFR C677T genotype and late-onset MDD and assess whether this may be affected by brain magnetic resonance imaging (MRI) hyperintensities. METHODS: Authors recruited 39 elderly patients with MDD with first episode occurring after age 50 and 20 comparison subjects and assessed total plasma homocysteine levels, MTHFR genotype, and brain MRIs. RESULTS: Plasma total homocysteine levels were higher in elderly patients with late-onset MDD versus comparison subjects. The association did not change after controlling for MRI hyperintensities, and the distribution of MTHFR C677T genotype was not different between the groups. CONCLUSIONS: In this exploratory study, elevated homocysteine levels were associated with late-onset MDD, and the association did not appear to be mediated by vascular pathology as identified by brain MRI hyperintensities.     

Is depression a disconnection syndrome? Meta-analysis of diffusion tensor imaging studies in patients with MDD

Background: Many studies using diffusion tensor imaging (DTI) have demonstrated impaired white matter integrity in patients with major depressive disorder (MDD), with significant results found in diverse brain regions. We sought to identify whether there are consistent changes of regional white matter integrity in patients with MDD, as shown by decreased fractional anisotropy in DTI. Method: A systematic search strategy was used to identify relevant whole brain voxel-based DTI studies of patients with MDD in relation to comparison groups. Relevant databases were searched for studies published between January 1994 and February 2011 using combinations of the terms "DTI" or "diffusion tensor;" "whole brain" or "voxel-based;" and "depress*." Using the studies that met our inclusion criteria, we performed a meta-analysis of the coordinates of decreased fractional anisotropy using the activation likelihood estimation (ALE) method, which detects 3-dimensional conjunctions of coordinates from multiple studies, weighted by sample size. We then used DTIquery software for fibre tracking to locate the fascicles involved in each region. Results: We included 11 studies with a combined sample of 231 patients with MDD and 261 comparison participants, providing 50 coordinates of decreased fractional anisotropy. Our meta-analysis identified 4 consistent locations of decreased fractional anisotropy in patients with MDD: white matter in the right frontal lobe, right fusiform gyrus, left frontal lobe and right occipital lobe. Fibre tracking showed that the main fascicles involved were the right inferior longitudinal fasciculus, right inferior fronto-occipital fasciculus, right posterior thalamic radiation and interhemispheric fibres running through the genu and body of the corpus callosum. Limitations: The number of studies included was relatively small, and the DTI data acquisition and analysis techniques were heterogeneous. The ALE method cannot handle studies with no significant group differences. Conclusion: Voxel-based analysis of DTI studies of patients with MDD consistently identified decreased fractional anisotropy in the white matter fascicles connecting the prefrontal cortex within cortical (frontal, temporal and occipital lobes) and subcortical areas (amygdala and hippocampus). This isstrong evidence for the involvement of these neural circuits in the pathology of MDD.     

Regional cerebral blood flow in depressed patients with white matter magnetic resonance hyperintensity.

BACKGROUND: Functional neuroimaging studies have consistently demonstrated decreased regional cerebral blood flow (rCBF) or metabolism in the frontal lobe, temporal lobe, or anterior cingulate gyrus of depressed patients. On the other hand, white matter hyperintensity as defined by magnetic resonance imaging (MRI) has been the most consistently replicated finding in structural neuroimaging studies on depression; however, these functional and structural neuroimaging findings of depression have not been well integrated. We aimed to clarify the possible associations of MRI-defined subcortical hyperintensities with rCBF changes in depressed patients. METHODS: Twelve depressed patients with subcortical hyperintensities defined by MRI, 11 depressed patients without MRI hyperintensities, and 25 healthy volunteers underwent 99mTc ECD SPECT. Group comparisons of their rCBF and correlation analysis between MRI hyperintensity and rCBF in patients were performed with a voxel-based analysis using statistical parametric mapping (SPM) software. RESULTS: Depressed patients showed decreased rCBF compared with control subjects in the frontal lobe, temporal lobe, and anterior cingulate gyrus whether subcortical hyperintensity existed or not; however, the patients with MRI hyperintensity showed decreased rCBF in the thalamus, basal ganglia, and brainstem in addition to cortical areas. Further, the score for white matter hyperintensity correlated negatively with rCBF in subcortical brain structures, including the thalamus and right basal ganglia. CONCLUSION: Our study indicates that depressed patients with MRI hyperintensities may have dysfunction in subcortical brain structures in addition to dysfunction in the fronto-temporal cortical structures.