多发性硬化患者颈髓扩散张量成像研究

目的 通过扩散张量成像研究多发性硬化患者常规MRI表现正常脊髓(NASC)的改变,并探讨其临床应用价值.方法 采用平面回波成像技术对13 例多发性硬化患者和13 例健康志愿者施行颈髓扩散张量成像检查,分别测量第2 ~ 5 颈椎(C2 ~ 5)水平前索、后索、侧索及灰质兴趣区的部分各向异性(FA)值及平均扩散率(MD)值,比较两组之间所存在的差异性;相关分析检验多发性硬化组患者FA值和MD 值与扩展残疾状态量表(EDSS)评分之间的关系.结果 与正常对照组相比,多发性硬化组患者C2 ~ 5 前索、侧索、后索和灰质NASC 的FA 值降低、MD 值升高(均P < 0.05);相关分析显示,FA 值与EDSS 评分呈负相关(r = - 0.328 ~ - 0.207,P = 0.001 ~ 0.035),各兴趣区MD 值与EDSS 评分呈正相关(r =0.234 ~ 0.409,P = 0.000 ~ 0.018).结论 多发性硬化患者常规MRI 表现比正常脊髓的FA 值降低,提示存在隐匿性病变.脊髓扩散张量成像对多发性硬化患者临床评价和疗效判断有一定应用价值.     

视神经脊髓炎和多发性硬化患者颈髓扩散张量成像研究

目的通过扩散张量成像(DTI)比较视神经脊髓炎和多发性硬化患者与正常对照者常规MRI表现正常脊髓的扩散性差异,并探讨其临床应用价值。方法采用平面回波成像技术对10例视神经脊髓炎、14例多发性硬化患者和13例正常对照者进行颈髓DTI检查,分别测量颈椎C2~5水平前索、侧索、后索和灰质兴趣区的部分各向异性(FA)和平均扩散率(MD)。结果与正常对照组相比,视神经脊髓炎组患者前索、侧索、后索FA值降低(均P0.05),左侧侧索、后索、灰质MD值升高(均P≤0.05);多发性硬化组患者右侧侧索、后索FA值降低(均P0.05)。与多发性硬化患者相比,视神经脊髓炎患者侧索FA值更低,左侧侧索和右侧后索MD值更高(均P0.05)。结论 DTI可以检出视神经脊髓炎和多发性硬化患者常规MRI表现正常脊髓的水分子扩散异常,进而发现二者脊髓扩散指标的差异性,为早期诊断与鉴别诊断提供重要信息。     

多发性硬化患者MRI扩散张量成像脑白质束示踪的三维仿真定量研究

目的 研究多发性硬化(MS)患者脑白质束示踪的三维仿真影像表现,评价其定量结果与残疾状态扩展评分(EDSS)的相关性. 方法 对28例MS患者(MS组)和28名健康自愿者(对照组)通过MRI扩散张量成像扫描进行脑白质束示踪,测量示踪纤维数和示踪纤维密度,并应用配对t检验比较两组间差异;对MS组脱髓鞘斑块、正常表现脑白质和对照组感兴趣区的ADC值和FA值进行方差分析,使用线性回归模型计算MS组脑白质束示踪的定量结果与EDSS评分的相关性. 结果 在MS组脑白质束示踪三维仿真图像中可直接观察到脑白质束的受损和减少.MS组的示踪纤维数(2220±100)和示踪纤维密度(0.75±0.04)明显低予对照组(2750±70、0.93±0.02),差异有统计学意义(P＜0.05).MS组脱髓鞘斑块、正常表现脑白质和对照组感兴趣区的ADC值依次下降,分别为(1.23 ±0.13)× 10-3 mm2/s、(0.76±0.09)× 10-3 mm2/s、(0.63 ±0.10)×10-3 mm2/s; FA值依次升高,分别为0.24±0.04、0.42±0.07、0.48±0.06,差异均有统计学意义(P＜0.05).MS组示踪纤维数和示踪纤维密度都与EDSS评分呈负相关关系(r=-0.782,P=0.000;r=-0.771,P=0.000). 结论 通过MRI扩散张量成像扫描进行脑白质束示踪可以发现MS患者脑白质束的受损情况,其较常规MRI能提供更多的空间信息.     

多发性硬化患者的磁化传递及弥散张量成像特点

目的比较多发性硬化(MS)患者脑内病灶、表现正常脑白质(NAWM)及健康志愿者脑白质的磁化传递及弥散特性的差异,探讨MS患者的磁化传递率(MTR)与平均弥散率(MD)的相关性。方法分别对24例复发缓解型MS患者和24名健康志愿者行常规MRI、磁化传递成像(MTI)及弥散张量成像(DTI),经处理后得到相应的MTR、MD及各向异性分数(FA)图。测量MS病灶、对侧NAWM及健康志愿者相应脑白质区域的MTR、MD及FA值。结果MS患者病灶的平均MTR值(23.49%±5.16%)明显低于NAWM组(29.49%±3.38%)及健康对照组(32.78%±3.42%,F=101.44,P<0.01);病灶的平均FA值(0.32±0.09)也明显低于NAWM组(0.42±0.09)及对照组(0.51±0.09,F=95.41,P<0.01);而病灶的平均MD值[(1.10±0.17)×10-3mm2/s]明显高于NAWM组[(0.92±0.13)×10-3mm2/s]及对照组[(0.76±0.04)×10-3mm2/s,F=144.89,P<0.01]。与MS患者T1WI等信号病灶相比,低信号病灶的MTR值及FA值降低,而MD值升高。MS患者病灶的MTR值与MD值显著相关,而NAWM的MTR与MD值无明显相关性。结论MTI和DTI的指标可以反映MS患者脑内不同部位病理变化的不同,为常规MRI提供补充信息。     

多发性硬化患者血清尿酸水平变化及与致残状况相关性研究

目的 探讨多发性硬化(MS)患者血清尿酸水平变化及其与致残状况的相关性.方法 收集复发缓解型多发性硬化患者42例,作为MS组,将MS组患者根据不同发作时期再分为MS-复发组和MS-缓解组；收集健康体检者42例作为对照组；比较MS与对照组间以及MS-复发组与MS-缓解组间血清尿酸水平,EDSS量表评价所有MS患者致残状况,对MS患者血清尿酸水平与EDSS评分进行相关性分析.结果 MS组血清尿酸浓度为(205.19±42.99) μmol/L,显著低于正常对照人群的(301.81±87.98) μmol/L,两组间比较差异有统计学意义(t=2.143,P＜0.05)；MS组EDSS评分为(3.9±1.1)分,较正常人群表现出显著的功能障碍；MS-复发组血清尿酸浓度为(171.47±38.33)μmol/L,显著低于MS-缓解组的(238.91±47.64) μmol/L,两组间比较差异有统计学意义(t=1.917,P＜0.05)；MS患者血清尿酸水平与其EDSS评分呈显著负相关(r=-0.365,P=0.011).结论 机体内尿酸水平的缺失在某种程度上可以影响多发性硬化的发生与进展,还与MS患者功能残障的发生及发展密切相关.     

血管周围间隙与多发性硬化的相关性研究

目的研究血管周围间隙与多发性硬化的相关性。方法对38例多发性硬化患者(多发性硬化组)及50名健康体检者(对照组)进行头颅MRI检查,计数其血管周围间隙并测量其直径。对结果进行组间比较。结果多发性硬化组患者血管周围间隙检出率(42.1%,16/38)明显高于对照组(16.0%,8/50)(P0.01)。多发性硬化组患者血管周围间隙的数目[(5.4±2.4)个/例]明显多于对照组[(2.7±2.0)个/例](P0.01)。多发性硬化组患者血管周围间隙的直径[(3.0±1.0)mm]明显大于对照组[(2.2±0.7)mm](P0.05)。线性回归分析显示,对照组中血管周围间隙的数目、直径均与年龄呈正相关(r1=0.857,r2=0.956,均P0.01)。结论血管周围间隙与多发性硬化有一定的相关性。     

肌萎缩侧索硬化症患者非锥体束的磁共振扩散张量成像研究

目的 研究肌萎缩侧索硬化症(ALS)患者非锥体束区域磁共振扩散张量成像(DTI)的特点.方法 选择ALS患者(病例组)21例及健康志愿者(健康对照组)20名,行轴位MRDTI扫描,选取感兴趣区(ROI),测量部分各向异性(FA)和平均扩散系数(MD).结果 病例组胼胝体压部(0.73±0.087)(u=-2.004,P<0.05)、丘脑(0.29±0.020)(u=-3.580,P<0.01)的FA值与健康对照组(0.79±0.034,0.32±0.010)比较,明显减低;两组间各ROI水平MD的差异无统计学意义.结论 除中枢运动传导系统外,ALS患者的胼胝体压部、丘脑亦被累及,ALS更有可能是一种以运动系统损害为主的多系统变性疾病.     

磁共振扩散张量成像技术在外伤性视神经病中应用研究

目的 探讨磁共振扩散张量成像技术在评价外伤性视神经病中的作用. 方法选择6例单侧外伤性视神经病患者,采用磁共振扩散张蛩成像技术检测双侧视神经.应用DTV2和Volume One 1.44软件测量视神经的部分各向异性值、平均表观扩散系数,并进行损伤眼和正常眼的自身对比;应用神经白质纤维柬追踪技术显示视神经的空间完整性和连续情况.结果 所有患者眶内段视神经显示良好,2例患者双侧管内段显示欠佳.6例患者损伤眼眶内段视神经部分各向异性平均值较正常眼明显下降,分别为0.244±0.067和0.452±0.053,差异有统计学意义(P=0.000);平均表观扩散系数平均值较正常眼明显上升,分别为(1.417±0.121)×10<'-3>mm<'2>/s和(1.087±0.118)×10<'-3>mm<'2>/s,差异有统计学意义(P=0.003).4例患者可以获得用于评估双侧视神经空间连接情况的扩散张量纤维束成像图,损伤眼和正常眼之间存在明显差异.结论磁共振扩散张量成像技术能够为评估外伤性视神经病的视神经纤维病理情况提供有价值的信息.     

复发缓解型多发性硬化患者脑灰质弥散张量成像研究

目的利用弥散张量成像(DTI)直方图分析,明确复发缓解型多发性硬化(RRMS)患者表现正常脑灰质(NAGM)是否存在隐匿性损伤,并研究脑灰质DTI直方图指标与扩展残疾功能状态量表(EDSS)评分的相关性。方法对24例RRMS患者和24名性别及年龄匹配的健康志愿者行常规磁共振成像(MRI)和DTI检查,分割提取NAGM后,绘制出NAGM的平均弥散率直方图并对其进行分析。结果RRMS患者NAGM的平均弥散率[(1·134±0·086)×10-3mm2/s]明显高于健康志愿者[(0·993±0·042)×10-3mm2/s,t=7·198,P<0·01],平均弥散率直方图峰位置[(0·880±0·089)×10-3mm2/s]也明显高于健康志愿者[(0·812±0·017)×10-3mm2/s,t=3·685,P=0·001],而平均弥散率直方图峰高(6·138‰±1·371‰)明显低于健康志愿者(8·889‰±1·339‰,t=7·032,P<0·01)。RRMS患者NAGM的平均弥散率直方图各指标间的相关性明显高于健康志愿者。在RRMS患者,所有NAGM的平均弥散率直方图指标与EDSS评分均无相关性。结论RRMS患者的NAGM内存在隐匿性损伤。     

视神经脊髓炎MRI诊断

视神经脊髓炎为一种自身免疫性炎性疾病,主要累及视神经和脊髓,脑组织也可出现病灶,但其MRI表现与经典的多发性硬化有所不同.常规MRI可以发现视神经炎和脊髓炎病灶.MRI新技术中以扩散张量成像、磁共振波谱分析及磁化传递成像的研究较多.     

Early silent microstructural degeneration and atrophy of the thalamocortical network in multiple sclerosis

Recent studies on patients with clinically isolated syndrome (CIS) and multiple sclerosis (MS) demonstrated thalamic atrophy. Here we addressed the following question: Is early thalamic atrophy in patients with CIS and relapsing‐remitting MS (RRMS) mainly a direct consequence of white matter (WM) lesions—as frequently claimed—or is the atrophy stronger correlated to “silent” (nonlesional) microstructural thalamic alterations? One‐hundred and ten patients with RRMS, 12 with CIS, and 30 healthy controls were admitted to 3 T magnetic resonance imaging. Fractional anisotropy (FA) was computed from diffusion tensor imaging (DTI) to assess thalamic and WM microstructure. The relative thalamic volume (RTV) and thalamic FA were significantly reduced in patients with CIS and RRMS relative to healthy controls. Both measures were also correlated. The age, gender, WM lesion load, thalamic FA, and gray matter volume‐corrected RTV were reduced even in the absence of thalamic and extensive white matter lesions—also in patients with short disease duration (≤24 months). A voxel‐based correlation analysis revealed that the RTV reduction had a significant effect on local WM FA—in areas next to the thalamus and basal ganglia. These WM alterations could not be explained by WM lesions, which had a differing spatial distribution. Early thalamic atrophy is mainly driven by silent microstructural thalamic alterations. Lesions do not disclose the early damage of thalamocortical circuits, which seem to be much more affected in CIS and RRMS than expected. Thalamocortical damage can be detected by DTI in normal appearing brain tissue. Hum Brain Mapp 37:1866–1879, 2016. © 2016 Wiley Periodicals, Inc .     

弥散张量成像在颅内环形强化病变中的诊断价值

目的 探讨弥散张量成像(diffusion tensor imaging,DTI)对颅内环形强化病变的诊断价值.方法 53例颅内单发环形强化病例术前行DTI扫描,分别测量病变坏死区、灶周水肿区及对侧正常脑实质的平均弥散系数(MD)值及各向异性分数(FA)值.并通过弥散张量纤维束成像(diffusiontensor tracking,DTT)观察病灶与白质纤维束的关系.结果 脑脓肿坏死区的MD值为(0.60±0.13)×10-3 mm2/s,FA值为0.18±0.03,高级别星形细胞瘤MD值为(2.76±0.26)×10-3mm2/s,FA值为0.07±0.02,脑转移瘤MD为(2.82±0.29)×10-3mm2/s,FA值为0.06±0.02,前者与后两者间差异有统计学意义(P<0.01).高级别星形细胞瘤水肿区的FA值(0.23±0.06)与脑转移瘤(0.17±0.06)和脑脓肿(0.15±0.03)两者水肿区FA值差异有统计学意义(P<0.01).DTT可以较准确地反映病灶与白质纤维束的关系,为手术治疗及评估预后提供依据.结论 坏死区MD值及FA值有助于脑脓肿与环形强化脑肿瘤的鉴别;水肿区FA值有助于脑星形细胞瘤与转移瘤、脑脓肿的鉴别;DTT能够为优化手术方案及评估预后提供一定帮助.     

皮质下血管性轻度认知障碍患者的多模式磁共振研究

目的 明确对皮质下缺血性血管病（subcortical ischemic vascular disease,SIVD）患者早期认知损害较 为敏感的磁共振成像（magnetic resonance imaging,MRI）指标。 方法 32例SIVD患者经过认知测试,被分为无认知障碍（no cognitive impairment,NCI）组18例,血管性 轻度认知障碍（vascular mild cognitive impairment,VaMCI）组14例,分析其认知测试指标与MRI参数之间 的关系。 结果 NCI组、VaMCI组全脑白质（whole brain white matter,WBWM）平均弥散度（mean diffusivity,MD） 分别为（0.84±0.03）×10-9·m2·s-1和（0.89±0.05）×10-9·m2·s-1,表观正常白质（normal appearing white matter,NAWM）的MD分别为（0.87±0.04）×10-9·m2·s-1和（0.92±0.05）×10-9·m2·s-1,差异 均有显著性（P均为0.003）;NCI组、VaMCI组WBWM各向异性分数（fractional anisotropy,FA）分别为 （0.37±0.02）和（0.35±0.02）,两组有显著差异（P =0.002）,两组NAWM的FA分别为（0.35±0.02）和 （0.33±0.02）,差异亦有显著性（P =0.001）。SIVD患者WBWM的MD值、NAWM的MD值和FA值与注意- 执行均相关,相关系数分别为－0.401（P =0.031）、－0.422（P =0.023）和0.409（P =0.027）,NAWM的 MD值与记忆相关,相关系数为－0.377（P =0.044）,多元逐步回归显示仅NAWM的MD值与注意-执行 （β=－0.453,P =0.009）、记忆（β=－0.414,P =0.019）和总体认知（β=－0.410,P =0.02）独立负相 关。而常规MRI参数未显示组间差异,与认知功能亦未见相关性。 结论 MRI弥散张量成像（diffusion tensor imaging,DTI）可以作为早期识别SIVD患者认知障碍的有效 手段。NAWM的MD值在认知障碍早期即下降,并与多项认知域独立相关,是较为敏感的DTI指标。     

Diffusion tensor imaging in multiple sclerosis: a tool for monitoring changes in normal-appearing white matter

Our objectives were to determine the reproducibility of diffusion tensor imaging (DTI) in volunteers and to evaluate the ability of the method to monitor longitudinal changes occurring in the normal-appearing white matter (NAWM) of patients with multiple sclerosis (MS). DTI was performed three-monthly for one year in seven MS patients: three relapsing-remitting (RRMS), three secondary progressive (SPMS) and one relapsing SP. They were selected with a limited cerebral lesion load. Seven age- and sex-matched controls also underwent monthly examinations for three months. Diffusivity and anisotropy were quantified over the segmented whole supratentorial white matter, with the indices of trace (Tr) and fractional anisotropy (FA). Results obtained in volunteers show the reproducibility of the method. Patients had higher trace and lower anisotropy than matched controls (P < 0.0001). Over the follow-up, both Tr and FA indicated a recovery after the acute phase in RRMS and a progressive shift towards abnormal values in SPMS. Although this result is not statistically significant, it suggests that DTI is sensitive to microscopic changes occurring in tissue of normal appearance in conventional images and could be useful for monitoring the course of the disease, even though it was unable to clearly distinguish between the various physiopathological processes involved.     

Longitudinal thalamic diffusion changes after middle cerebral artery infarcts

BACKGROUND: Cerebral infarcts are responsible for functional alterations and microscopic tissue damage at distance from the ischaemic area. Such remote effects have been involved in stroke recovery. Thalamic hypometabolism is related to motor recovery in middle cerebral artery (MCA) infarcts but little is known concerning the tissue changes underlying these metabolic changes. Diffusion tensor imaging (DTI) is highly sensitive to microstructural tissue alterations and can be used to quantify in vivo the longitudinal microscopic tissue changes occurring in the thalamus after MCA infarcts in humans. METHODS: Nine patients underwent DTI after an isolated MCA infarct. Mean diffusivity (MD), fractional anisotropy (FA), and thalamic region volume were measured from the first week to the sixth month after stroke onset in these patients and in 10 age matched controls. RESULTS: MD significantly increased in the ipsilateral thalamus between the first and the sixth month (0.766 x 10(-3) mm(2)/s first month; 0.792 x 10(-3) mm(2)/s third month; 0.806 x 10(-3) mm(2)/s sixth month). No significant modification of FA was detected. In six patients, the ipsilateral/contralateral index of MD was higher than the upper limit of the 95% CI calculated in 10 age matched controls. An early decrease of MD preceded the increase of ipsilateral thalamic diffusion in one patient at the first week and in two other patients at the first month. CONCLUSION: After MCA infarcts, an increase in diffusion is observed with DTI in the ipsilateral thalamus later than 1 month after the stroke onset. This is presumably because of the progressive loss of neurons and/or glial cells. In some patients, this increase is preceded by a transient decrease in diffusion possibly related to an early swelling of these cells or to microglial activation. Further studies in larger series are needed to assess the clinical correlates of these findings.     

Thalamic diffusion and volumetry in temporal lobe epilepsy with and without mesial temporal sclerosis

PURPOSE: As an important connection within the limbic system, considerable attention has been paid to thalamic pathology in temporal lobe epilepsy (TLE). Magnetic resonance imaging (MRI) volumetric studies have yielded variable results and have largely been focused on TLE with mesial temporal sclerosis (TLE+). Diffusion tensor imaging (DTI) provides unique information on microstructure based on the measurement of water diffusion. To date, DTI properties of thalamus have not been well characterized in adult TLE patients with unilateral MTS or without MTS (TLE-). The purpose of this study was to investigate the status of thalamic integrity by using DTI as well as volumetric MRI in adult TLE+ and TLE- patients. METHOD: In 17 unilateral TLE+ patients, 10 TLE- patients and 26 controls, the thalamus was segmented by using an automated atlas-based method. Mean diffusivity (MD), fractional anisotropy (FA) and volume were then quantified from DTI and 3D T1-weighted scans. RESULTS: No significant changes were found in either DTI parameters or volume of thalamus in TLE- patients, as compared to healthy controls. However, both DTI parameters and MRI volumetry showed bilateral thalamic pathology in TLE+ patients, as compared to healthy controls. Also, TLE+ patients showed significant reduction of thalamic volume as compared to TLE- patients. In addition, thalamic FA ipsilateral to seizure focus showed significant correlation with age at onset of epilepsy in TLE+ patients. CONCLUSION: Our finding demonstrates bilateral pathology of thalamus in unilateral TLE+ patients. The discrepancy in thalamic pathology between TLE+ and TLE- patients suggests that along with differences in mesial temporal pathology, TLE+ and TLE- have unique extratemporal structural abnormalities.     

1H MRSI comparison of white matter and lesions in primary progressive and relapsing-remitting MS

OBJECTIVE: To compare brain metabolite levels in patients with primary progressive (PP) and relapsing remitting (RR) MS and controls. Hypotheses: (1) creatine (Cr), a putative marker of gliosis, is elevated and N-acetylaspartate (NAA), a putative marker of axonal density and functional integrity, is reduced in PPMS lesions and normal appearing white matter (NAWM) compared to control white matter; (2) The pattern of metabolite change in PPMS is different than in RRMS. METHODS: MRI and proton magnetic resonance spectroscopic imaging (1H MRSI) were collected from 15 PPMS patients, 13 RRMS patients, and 20 controls. RESULTS: Cr was increased in PPMS NAWM compared to controls (P=0.035), and compared to RRMS NAWM (P=0.038). Cr was increased in focal MRI lesions from PPMS compared to lesions from RRMS (P=0.044) and compared to control white matter (P=0.041). NAA was similarly reduced in PPMS and RRMS NAWM compared to control. NAA was similarly reduced in PPMS and RRMS lesions, compared to control white matter. CONCLUSIONS: Creatine is higher in PPMS than RRMS NAWM and focal lesions. This observation is consistent with the notion that progressive disability in PPMS reflects increased gliosis and axonal loss whereas disability in RRMS reflects the cumulative effects of acute inflammatory lesions and axonal loss.     

Neuroanatomical correlates of emotion-processing in children with unilateral brain lesion: A preliminary study of limbic system organization

In this study, MRI and DTI were employed to examine subcortical volume and microstructural properties (FA, MD) of the limbic network, and their relationships with affect discrimination in 13 FL (6 right FL, M = 10.17 years; 7 left FL; M = 10.09) and 13 typically-developing children (TD; M = 10.16). Subcortical volume of the amygdala, hippocampus and thalamus and FA and MD of the fornix and anterior thalamic radiation (ATR) were examined. Results revealed no group differences across emotion-perception tasks or amygdalar volume. However, contrasting neuroanatomical patterns were observed in right versus left FL youth. Right FL participants showed increased left hippocampal and thalamic volume relative to left FL participants; whereas, the latter group showed increased right thalamic volume. DTI findings also indicated right FL children show greater MD of right fornix than other groups, whereas, left FL youth showed greater MD of left fornix. Right FL youth also showed lower FA of right fornix than left FL children, whereby the latter showed greater FA of left fornix and ATR. Differential associations between DTI indices and auditory/visual emotion-perception were observed across FL groups. Findings indicate diverging brain-behavioral relationships for emotion-perception among right and left FL children.