扩散张量成像评估基底核区出血和缺血性病变对皮质脊髓束的影响

背景：基底核区出血性和缺血性病变,最容易造成相邻皮质脊髓束损伤,从而导致肢体运动功能程度障碍。功能磁共振扩散张量成像技术能真实有效地显示脑内白质结构,尤其是发生病变时,相邻和相关的白质纤维结构受到不同程度的影响和破坏,以扩散张量成像的各向异性指数最为敏感。 目的：应用扩散张量成像技术评估左侧基底核缺血性和出血性病变对皮质脊髓束通路的影响,并比较两种情况下皮质脊髓束通路各向异性指数的差异。 设计、时间及地点：对比观察,于2005-10/2008-12在昆明医学院第一附属医院磁共振室完成。 对象：左侧基底核出血患者20例,左侧基底核缺血性病变患者27例。 方法：利用GE 1.5T扫描仪及SUN工作站行全脑数据收集和后处理,在各向异性指数图像上分别测量延髓、脑桥、大脑脚、基底核、放射冠及半卵圆中心等层面的皮质脊髓束通路走行区各向异性指数的测量。兴趣区大小的确定由个体纤维束轴位图上其结构所决定,以不超出该结构的范围、同时有2人对兴趣区大小进行肯定为准。 主要观察指标：常规磁共振明确基底核区出血和缺血性病变患者,采集扩散张量成像数据并在工作站的扩散张量成像软件进行皮质脊髓束走行区域各向异性指数测量和分析。 结果：左侧基底核区的出血、缺血性病变对左侧皮质脊髓束通路各个水平层面结构的影响程度不同,其各向异性指数的统计学分析,α=0.05。缺血及出血性病变患者延髓水平皮质脊髓束的各向异性指数差异无显著性意义(P=0.05);脑桥水平直至半卵圆中心各层皮质脊髓束的各向异性指数差异有显著性意义(P < 0.001);尤其是基底核层面和放射冠层面的P值最小,又以放射冠层面最明显。 结论：扩散张量成像结果显示,基底核区缺血性病变对大脑脚层面及其以上的皮质脊髓束的影响较出血性病变大。     

无先兆偏头痛患者大脑结构和功能异常的MRI研究

目的研究无先兆偏头痛患者大脑结构和功能异常的MRI表现。方法选取30例无先兆偏头痛患者作为观察组,同期25例健康志愿者作为对照组。Signa Excite 3.0 T磁共振扫描仪,采用平面回波成像序列采集对象静息态功能MRI图像,采用单次激发回波平面成像序列采集脑白质DTI图像。采用肯德尔系数评估静息态局部一致性,采用基于纤维束追踪空间统计分析技术(TBSS)分析脑白质纤维的分数各项异性(FA)、平行弥散系数(RD)、轴向弥散系数(AD)、以及平均弥散系数(MD)。结果与对照组比较,观察组患者多个脑区存在局部一致性降低,包括左侧前后扣带回、左侧颞下回、左侧梭状回、右侧中央前后回、右侧额中回、右侧舌回局部一致性减弱(FEW校正,P0.05)。观察组患者双侧大脑脚、双侧内囊后肢、右侧内囊前肢、右侧上纵束、右侧胼胝体体部和压部、右侧上放射冠和后放射冠、左侧扣带的FA值显著降低(FEW校正,P0.05);双侧上放射冠和后放射冠、双侧扣带、双侧丘脑后辐射、双侧上纵束、右侧大脑脚、右侧内囊前后肢以及右侧胼胝体体部和压部的RD值显著升高(FEW校正,P0.05);胼胝体体部和压部,右侧上放射冠和后放射冠,以及右侧上纵束的MD值显著升高(FEW校正,P0.05);两组各脑区的AD值无显著性差异(FEW校正,P0.05)。结论无先兆偏头痛患者大脑静息态局部一致性和脑白质纤维束存在改变,且明显区别于健康志愿者。     

磁共振扩散张量成像在缺血缺氧脑病患儿中的临床应用

目的探讨磁共振扩散张量成像(DTI)在缺血缺氧脑病患儿中的应用价值。方法前瞻性纳入2016-12—2018-12于河南中医药大学第一附属医院行MRI头颅平扫及DTI检查的年龄2岁患儿40例,所有患儿在围生期均有缺氧缺血脑病史,根据最终随访结果分为脑瘫组及非脑瘫组各20例。测量双侧大脑脚、内囊前肢、内囊膝部、内囊后肢、半卵圆中心、皮质脊髓束、下纵束、丘脑后辐射、额叶白质、顶叶白质、胼胝体膝部、胼胝体体部及胼胝体压部的FA值。结果 2组间双侧大脑脚、内囊后肢、半卵圆中心、皮质脊髓束、下纵束、丘脑后辐射、顶叶白质、胼胝体膝部、胼胝体体部、胼胝体压部FA值差异均有统计学意义(P0.05),而双侧内囊前肢、内囊膝部、额叶白质FA值差异无统计学意义(P0.05)。结论 DTI可以定量评估缺血缺氧脑病患儿的损伤程度,有助于早期评估病情及预测预后。     

2型糖尿病合并认知功能障碍患者的脑白质结构变化的影像学特征分析

目的探讨2型糖尿病(T2DM)合并认知功能障碍(T2DM-CI)患者的脑白质结构变化特征。方法纳入33例T2DM-CI患者(T2DM-CI组)、35例T2DM无合并认知功能障碍患者(T2DM-nonCI组)及43例无DM和认知功能障碍者为对照组。应用MR DTI序列检查,利用图集分割的方法计算脑白质20条纤维束弥散参数,比较组间差异,并与认知功能进行相关性分析。结果 3组受试者脑白质纤维束FA值呈下降趋势,MD值呈上升趋势。T2DM-CI组与T2DMnon CI组比较,双侧皮质脊髓束、右侧扣带束海马、胼胝体体部、胼胝体压部、右侧下额枕束、右侧下纵束的FA值差异有显著性(均P 0. 05/20条纤维束)。其中,胼胝体压部、右侧下纵束与语言功能显著相关;双侧皮质脊髓束,胼胝体压部与处理速度差异有显著性(均P 0. 05)。双侧皮质脊髓束、胼胝体压部、双侧下额枕束,双侧上纵束的MD值差异有显著性(均P 0. 05/20条纤维束)。其中,右侧下额枕束、右侧上纵束与语言功能差异有显著性(均P 0. 05)。结论T2DM-CI患者脑白质结构完整性受到破坏,其中胼胝体压部、下纵束、下额枕束、上纵束损伤可能与T2DM-CI患者语言功能受损相关,皮质脊髓束、胼胝体压部损伤可能与处理速度受损相关。     

弥散张量成像在高血压性脑出血中的临床应用初探

目的 应用磁共振弥散张量成像技术观察基底节区高血压性脑出血皮质脊髓束的受损情况,为临床干预治疗提供可靠依据.方法 对9例基底节区HICH患者进行磁共振弥散张量成像检查,分别测量患侧皮质脊髓束受压区及健侧皮质脊髓束相应区域的FA值,并重建一名患者的FA图、方向编码彩色图、双侧皮质脊髓束3D纤维束图.结果 患侧皮质脊髓束的FA值均较对侧降低,两侧相比差异有显著性意义(t=4.9041,P<0.05);患侧皮质脊髓束区FA值下降百分比和NIHSS评分有明显相关性(r=0.8336,P<0.05);皮质脊髓束3D纤维束图可显示病变侧皮质脊髓束受损情况.结论 通过弥散张量成像可以了解基底节区HICH患者的皮质脊髓束的损伤情况,这有助于临床医生全面掌握病情,开展干预性治疗.     

应用弥散张量成像研究脑梗死后皮质脊髓束Wallerian变性与运动功能缺损的相关性

目的:应用弥散张量成像(DTI)研究脑梗死后皮质脊髓束Wallerian变性与神经运动功能缺损的相关性。方法:对11例单侧大脑中动脉供血区脑梗死的患儿进行了DTI研究。通过放置兴趣区(ROI)的方式获得定量部分各向异性(FA)和平均弥散量(MD)。ROI放置的部位包括:脑梗死区、脑梗死同侧内囊后支前部和大脑脚,以及上述部位对侧相应区域。根据手的运动情况将运动功能缺损分为轻、中和重3级。应用Mann-Whitney U检验确定差异有无显著性;应用Spearman相关检验确定皮质脊髓束DTI改变与神经运动功能缺损之间的相关性。结果:脑梗死同侧皮质脊髓束FA较对侧明显下降(P<0.05),但MD改变与对侧无明显差异(P>0.05)。FA下降与神经运动功能缺损之间存在明显相关性(r=-0.638,P=0.035)。结论:应用FA值的变化,DTI可以检测并定量分析儿童脑梗死后皮质脊髓束Wallerian变性,并可作为预测脑梗死后运动功能缺损的工具。     

基于小脑通路的弥散磁共振成像分析

目的探讨小脑-大脑皮层通路的白质连接模式。方法于2015年10月-2016年4月通过电子科技大学校园网公开招募20名健康被试并采集所有被试的弥散磁共振(dMRI)数据,通过概率性示踪法重建出小脑-大脑皮层之间的白质纤维束通路,包括齿状核-红核-丘脑-皮层(DTC)、额叶-脑桥-小脑(FPC)、顶叶-脑桥-小脑(PPC)、颞叶-脑桥-小脑(TPC)和枕叶-脑桥-小脑(OPC)。考察这些通路白质微结构的弥散参数,包括各向异性分数(FA)、平均扩散度(MD)、横向扩散度(AD)和径向扩散度(RD)。利用配对t检验考察各个纤维束弥散参数的对称性。结果在20名被试中均成功追踪出5组白质纤维束。DTC和OPC的各个参数均显示为双侧对称;TPC和PPC的FA存在不对称性,左侧高于右侧,差异有统计学意义(P0.05);左侧FPC和右侧PPC的RD值较对侧高,差异均有统计学意义(P0.05)。结论弥散磁共振数据能有效重构小脑-大脑间的白质纤维束,作为小脑输出纤维(DTC)的弥散参数具有双侧对称性。而额叶、顶叶、颞叶向小脑的输入纤维均显示双侧不对称性,这可能反映了小脑参与大脑非运动功能的不对称性。     

苯丙胺类物质依赖的脑弥散张量成像研究

目的 探讨苯丙胺类物质对脑白质结构的影响.方法 对11例苯丙胺类物质依赖者和6名正常对照进行磁共振弥散张量成像(diffusion tensor imaging,DTI)扫描及脑白质纤维束重建,比较两组的差异;同时分析有精神症状的苯丙胺类物质依赖者(n=7)与正常对照的DTI结果差异.结果 苯丙胺物质依赖组左右两侧皮质脊髓束数量均低于对照组(t=1.25,P<0.01;t=0.04,P=0.03),左侧扣带束FA值高于右侧(t=4.04,P<0.01)且与物质使用时间呈正相关(r=0.69,P<0.01);有精神症状的苯丙胺类物质依赖组左侧皮质脊髓束ADC值高于对照组(t=3.54,P=O.04)、扣带束ADC值左侧小于右侧(t=-2.62,P=0.04);有精神症状的苯丙胺物质依赖组DTI值与阳性和阴性症状量表各因子分无明显相关(P>0.05).结论 苯丙胺类物质依赖者大脑双侧皮质脊髓束及左扣带束受损.且左扣带束纤维受损随物质使用时间延长而加重;未见苯丙胺物质依赖者的精神症状与DTI值相关,但需要进一步证实.     

运动神经元疾病患者颈髓弥散张量成像研究

目的 研究运动神经元疾病颈髓弥散张量成像(DTI)特点,探讨DTI在运动神经元疾病中的诊断价值.方法 选取临床诊断为肌萎缩侧索硬化(ALS)患者16例、肯尼迪病(KD)患者12例及健康志愿者15名.分别行颈髓常规MRI及横断面DTI检查,测定各组C3、C5椎体水平层面颈髓前索区、后索区及舣侧皮质脊髓侧束区4个区域内感兴趣区(ROI)的表观弥散系数(apparent diffusion coefficient,ADC)和部分各向异性比值(fractional anisotropy,FA),并分析影像学参数与其病程、ALSFRS-R评分、肺功能等之间的关系.结果 ALS 组患者在C3与C5水平,前索、双侧皮质脊髓侧束的FA值较KD组、健康对照组显著降低(P<0.05),而KD组与健康对照组之间差异无统计学意义(P>0.05).3组在各不同位置的ADC值之间差异无统计学意义(P>0.05).ALS组在C3水平右侧皮质脊髓束FA值与患者ALSFRS-R评分呈正相关(r=0.52,P=0.041);各水平前索、双侧皮质脊髓束的FA值、ADC值与患者病程、肺功能之间无相关性.结论 FA值可反映颈髓皮质脊髓束的功能异常,可用于评估ALS患者上运动神经元的损伤程度,有利于运动神经元疾病的鉴别诊断.     

基于弥散张量成像的抑郁症生物学亚型研究

背景 抑郁症病因复杂且临床表现异质性高,神经影像学研究为抑郁症生物学亚型的探索提供了新契机。目前,采用结构磁共振数据（MRI）进行抑郁症亚型划分的研究十分有限。目的 使用弥散张量成像（DTI）和机器学习方法探索抑郁症的生物学亚型。方法 纳入2017年9月-2021年8月于北京安定医院就诊的、符合《精神障碍诊断与统计手册（第4版）》（DSM-IV）抑郁症诊断标准的患者127例,同期在医院附近社区通过广告招募与患者性别和年龄相匹配的80例健康对照组。采集所有受试者的DTI图像、人口学信息和临床资料。使用纤维束追踪空间统计（TBSS）方法和约翰霍普金斯大学（JHU）脑白质概率图谱提取纤维束各向异性分数（FA）,采用半监督学习方法划分抑郁症亚型,并比较不同亚型的患者组与健康对照组全脑白质纤维束FA值的差异。结果 抑郁症患者被划分为两种亚型,亚型I患者胼胝体、放射冠等广泛的纤维束FA值低于健康对照组（P<0.01,FDR校正）,亚型II患者在小脑中脚、左侧小脑上脚和左侧大脑脚的FA值高于健康对照组（P<0.01,FDR校正）。亚型I和亚型II患者基线期HAMD-17总评分差异无统计学...     

磁共振弥散张量成像在基底节区高血压脑出血致皮质脊髓束损伤中的应用研究

目的 探讨磁共振弥散张量成像(DTI)技术评价基底节区高血压脑出血(HICH)患者皮质脊髓束(CST)受损程度的意义及其与肌力恢复的关系.方法 徐州医学院附属医院神经外科自2006年11月至2009年5月行小骨窗开颅血肿清除术治疗单侧基底节区HICH患者35例,术后10 d应用3.0T磁共振DTI技术检测患者和10例健康志愿者CST,应用Functool软件进行图像分析观察CST损伤程度,HICH患者康复治疗2月后采用Brunnstrom标准进行肢体肌力检查,分析CST损伤程度与肢体肌力的相关性.结果 10例健康志愿者CST显示清晰.35例HICH患者CST受损的模式有3种:纤维束显示达正常侧的2/3或相仿(11例),患者肢体肌力恢复最好;纤维束显示小于正常侧的2/3(18例),患者肢体肌力恢复较好;纤维柬显示小于正常侧的1/3(6例),患者肢体肌力恢复最差.CST受损患者患侧的FA值均较健侧降低,差异有统计学意义(P<0.05).3种模式CST损伤患者患侧的FA值、肢体肌力不同,差异均有统计学意义(P=0.000).患者CST损伤程度与肌力恢复水平存在负相关关系(r=0.931,P=0.000).结论 应用磁共振DTI技术可显示脑内白质纤维束的走形及分布,能够早期检测HICH患者CST的损伤程度,对患者肢体运动功能损伤的评估、判断预后有重要的临床意义.     

Fractional anisotropy of the corticospinal tract in normal adults Preliminary study using a diffusion tensor imaging technique

BACKGROUND: The corticospinal tract is an important tract for conducting motor function. The majority of studies focus on lesions of the corticospinal tract on appearance and function, whereas observation of normal corticospinal pathways can also improve understanding of lesion outcomes. OBJECTIVE: To observe the normal adult corticospinal tract using a diffusion tensor imaging technique to analyze fractional anisotropy (FA) in different levels of the brain. DESIGN, TIME AND SETTING: Neuroimaging observation was performed in the MRI Department, First Affiliated Hospital of Kunming Medical College in China, from October 2005 to October 2008. PARTICIPANTS: A total of 30 healthy adults were selected from the Department of MRI, First Affiliated Hospital of Kunming Medical College in China, from October 2005 to October 2008, and people with nervous system symptoms and signs were excluded. METHODS: Participants with normal conventional MRI results underwent diffusion tensor imaging examination in a 1.5 T GE MRI (slice thickness 4-5 mm, slice gap 0) for gradient data acquisition from 15 directions. The scanning involved the entire brain from the inferior medulla oblongata to the inferior cranial plate. Imaging post-processing was performed to obtain FA values; a paired Mest was applied for statistical analysis.MAIN OUTCOME MEASURES: FA values of the bilateral corticospinal tract in the medulla oblongata, pons, cerebral peduncle, basal ganglia, corona radiata, and centrum semiovale. RESULTS: FA values in the medulla oblongata and centrum semiovale were similar (P> 0.01). FA values of left corticospinal tract were significantly greater than the right side in the pons, cerebral peduncle, basal ganglia and corona radiata (P< 0.01). CONCLUSION: FA values vary by brain levels, including pons, cerebral peduncle, basal ganglia, and corona radiata. Moreover, FA values of the left corticospinal tract pathway were greater than the right side, which may relate to right handedness.     

The corticospinal tract in Sturge-Weber syndrome: a diffusion tensor tractography study

OBJECTIVE: To utilize diffusion tensor tractography and evaluate the integrity of the corticospinal tract in children with unilateral Sturge-Weber syndrome (SWS). METHODS: Sixteen children (age: 1.5-12.3 years) with SWS involving one hemisphere and varying degrees of motor deficit, underwent magnetic resonance imaging (MRI) as part of a prospective clinical research study. Diffusion tensor imaging (DTI) was obtained and fiber tracking of the corticospinal tract was performed yielding average FA and ADC values along the pathway. These values were compared between the two hemispheres (affected vs. unaffected) and also correlated with the degree of motor deficits, after correction for age. RESULTS: Corticospinal tract FA values on the side of the affected hemisphere were lower (p=0.008) and ADC values were higher (p=0.011) compared to the normal side. Furthermore, FA and ADC values on the side of the angioma did not show the normal age-related variations, which the contralateral corticospinal pathway values did demonstrate. Although none of the patients had severe hemiparesis, those with moderate motor deficit had increased ADC values, as compared to those with mild (p=0.009) or no motor deficit (p=0.045). CONCLUSION: MRI with DTI shows abnormalities of the corticospinal tract in children with SWS even before severe motor impairment develops. Thus, DTI can be a clinically useful method to evaluate the integrity of the corticospinal tract in young children who are at risk for progressive motor dysfunction.     

磁共振弥散张量及纤维束成像在急性脑梗死的临床应用

目的探讨急性脑梗死病人梗死灶弥散张量的参数变化及对皮质脊髓束的影响,以早期判断病情、评估预后。方法急性脑梗死患者45例,入院及治疗后分别行NIHSS评分记为NIHSS1、NIHSS2,常规MRI、DWI、DTI/DTT检查,分析病灶FA值的变化及与皮质脊髓束的关系。结果①梗死灶FA值降低百分比和NIHSS1相关(r=0.411,P<0.01)。②45例患者中,皮质脊髓束完整(1级)者15例,病灶致使皮质脊髓束受压、移位(2级)者20例,皮质脊髓束中断(3级)者10例。皮质脊髓束的损伤程度与NIHSS2相关(r=0.894,P<0.01)。结论病灶FA值下降越明显,患者病情越重;皮质脊髓束破坏越严重,患者运动功能受损越重,预后越差。     

MRI Predicts Efficacy of Constraint-Induced Movement Therapy in Children With Brain Injury

Using resting state (RS) functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), we identified the predictors of clinical improvement following constraint-induced movement therapy (CIMT) in pediatric patients with chronic hemiplegia.From 14 children with congenital or acquired brain injury and 10 sex- and age-matched healthy controls, brain dual-echo, DTI and RS fMRI sequences were acquired before CIMT. The Quality of Upper Extremities Skills Test and the Gross Motor Function Measure (GMFM) were administered at baseline, at the end of CIMT (10 weeks), and after 6 months. Mean diffusivity and fractional anisotropy (FA) were measured in the lesion responsible for the clinical symptomatology, the affected and unaffected corticospinal tract (CST), motor transcallosal fibers, and uncinate fasciculus (as an internal control). Independent component analysis was used to identify the sensorimotor RS network. The ability of baseline MRI variables to predict clinical changes over time was assessed using multivariate linear models. At baseline, patients had increased mean diffusivity in the symptomatic lesion and decreased FA in the symptomatic lesion, affected corticospinal tract, and motor transcallosal fibers. A reduced RS functional connectivity was found in the bilateral cerebellum, left precentral gyrus, and right secondary sensorimotor cortex. At follow up, Quality of Upper Extremities Skills Test and GMFM scales improved significantly. Baseline average lesion FA predicted clinical improvement at week 10, and baseline functional connectivity of the right secondary sensorimotor cortex and cerebellum predicted GMFM improvement at month 6. DTI and RS fMRI offer promising and objective markers to predict clinical outcomes following CIMT in pediatric patients with congenital or acquired hemiplegia.     

Involvement of motor pathways in corticobasal syndrome detected by diffusion tensor tractography

Corticobasal syndrome (CBS) is a progressive parkinsonian disease characterized by cortical and subcortical neuronal loss. Although motor disabilities are a core feature of CBS, the involvement of motor pathways in this condition has not been completely clarified. We used magnetic resonance diffusion tensor imaging (DTI) to study corticospinal and transcallosal motor projections in CBS, and applied fiber tractography to analyze the axonal integrity of white matter projections. Ten patients with CBS were compared with 10 age‐matched healthy controls. Fiber tracts were computed using a Monte‐Carlo simulation approach. Tract‐specific mean values of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were determined. CBS patients showed a reduction of corticospinal tract (CST) fibers on the first affected side with significantly increased ADC and reduced FA values. In the corpus callosum (CC), particularly in the posterior trunk, patients also had significantly reduced fiber projections, with a higher ADC and lower FA than controls. This pattern indicates changes of the white matter integrity in both CST and CC. Thus, magnetic resonance DTI can be used to assess motor pathway involvement in CBS patients. © 2008 Movement Disorder Society     

Diffusion tensor imaging of pyramidal tract reorganization after pediatric stroke

Background

Plasticity of the developing motor tracts is a contributor to recovery of motor function after pediatric stroke. The mechanism of these plastic changes may be functional and/or structural in nature. The corticospinal tract (CST) represents the major pathway responsible for voluntary movement. Stroke-induced damage to the CST as well as to other motor tracts leads to motor deficits which may show favorable functional recovery particularly in the pediatric population.

Methods

We report the case of a 3-year-old girl demonstrating reorganization of the pyramidal tracts after an extensive left MCA territory stroke secondary to head trauma. Reorganization is characterized using serial diffusion tensor imaging (DTI) of the pyramidal tracts which contain the CST.

Results

Imaging shows decreased ipsi-lesional fractional anisotropy (FA) suggestive of Wallerian degeneration and increased contralesional FA.

Conclusions

These results point to plastic reorganization of the pyramidal tract post-stroke and the utility of DTI in recognizing these changes.     

Diffusion tensor imaging patterns differ in bulbar and limb onset amyotrophic lateral sclerosis

Background

Amyotrophic lateral sclerosis (ALS) is characterized by pronounced clinical heterogeneity in terms of onset and disease progression. Widespread changes in white matter fibres could be observed by diffusion tensor imaging (DTI), which detects alterations in the degree (diffusivity, ADC) and directedness (fractional anisotropy, FA) of proton movement. The aim of the current study was to determine whether different ALS onset types were reflected in different DTI brain patterns.

Methods

Seventeen patients with a diagnosis of ALS (6 bulbar, 11 limb onset) and seventeen age-matched controls received 1.5T DTI, where FA and ADC were analyzed using statistical parametric mapping.

Results

In ALS patients, an increased diffusivity in the white matter was found below the precentral gyrus and along the corticospinal tract (CST) right into the internal capsule. The FA was decreased in the posterior limb of internal capsule and in the subcortical white matter in the precentral gyrus. In bulbar onset increased diffusivity was found in the CST, whilst in limb onset, frontal subcortical areas displayed an increased diffusivity.

Conclusion

DTI changes can be regarded as prominent features in ALS. Herein we were able to demonstrate discriminating brain DTI patterns due to bulbar or limb onset.     

Association of White Matter Integrity With Executive Function and Antidepressant Treatment Outcome in Patients With Late-Life Depression

ObjectiveWhile patients with late-life depression (LLD) often exhibit microstructural white matter alterations that can be identified with diffusion tensor imaging (DTI), there is a dearth of information concerning the links between DTI findings and specific cognitive performance, as well as between DTI measures and antidepressant treatment outcomes.DesignNeuroimaging and cognitive tests were conducted at baseline in 71 older adults participating in a larger, 8-week duration antidepressant randomized controlled trial. Correlations between DTI measures of white matter integrity evaluated with tract-based spatial statistics, baseline neurocognitive performance, and prospective antidepressant treatment outcome were evaluated.ResultsFractional anisotropy (FA), an index of white matter integrity, was significantly positively associated with better cognitive function as measured by the Initiation/Perseveration subscale of the Dementia Rating Scale in the bilateral superior longitudinal fasciculus (SLF), bilateral SLF-temporal, and right corticospinal tract (CST). An exploratory analysis limited to these tracts revealed that increased FA in the right CST, right SLF, and right SLF-temporal tracts was correlated with a greater decrease in depressive symptoms. Increased FA in the right CST predicted a greater chance of remission, while increased FA in the right CST and the right SLF predicted a greater chance of treatment response.ConclusionIn late-life depression LLD subjects, white matter integrity was positively associated with executive function in white matter tracts which act as key connecting structures underlying the cognitive control network. These tracts may play a role as a positive prognostic factor in antidepressant treatment outcome.     

在体磁共振波谱及扩散张力成像观察肌萎缩性侧索硬化的病理变化的研究

目的结合磁共振波谱成像(MRSI)以及扩散张力成像(DTI)技术及磁共振影像(MRI)对肌萎缩性侧索硬化(ALS)进行对照研究,评价MRSI、DTI、MRI在ALS诊断中的作用。方法采用MRSI、DTI及MRI技术对ALS患者及对照组进行扫描,观察沿皮质脊髓束(CST)走行区域包括中央前回皮层下(SWM)、半卵圆中心(CS)、侧脑室旁白质(PV)、内囊后肢(PIC)、大脑脚(CP)的各向异性比(FA)以及平均扩散率(MD),以及SWM、PV、PIC平面氮乙酰门冬胺酸(NAA)与肌酸(Cr)比值在对照组及ALS患者的改变,并比较不同扫描序列在ALS诊断的作用。结果ALS的总FA较对照组明显降低(P<0.001),在CST走行区的SWM、CS、PV和PIC平面,ALS组的FA较对照组明显降低(P<0.05),MD在ALS组有升高的趋势,但无统计学差异。ALS组的NAA/Cr较对照组明显降低(P<0.05),在SWM和PV平面ALS组的NAA/Cr较对照组降低明显(P<0.05)。对T1WI、T2WI与FLAIR序列判断结果显示,对照组与ALS组间MRI的表现无明显差异。结论MRSI与DTI结合能够早期定量探测ALS患者CST的轴索损伤,SWM、CS、PV和PIC平面的FA,在SWM和PV的NAA/Cr为有效的指标。ALS与对照组MRI的表现则无明显差异。