复发性视神经脊髓炎脑扩散张量成像研究

目的利用扩散张量成像（DTI）探讨复发性视神经脊髓炎（RNMO）患者是否存在隐匿性脑组织损伤及其发生机制。方法对16例RNMO患者和16例性别和年龄匹配的正常志愿者脑组织的平均扩散系数（ND）和部分各向异性（FA）进行直方图和感兴趣区（ROI）分析，以P≤0．005为差异有统计学意义。结果与志愿者比较，RNMO患者脑的平均MD升高[脑组织：RNMO患者（0．95±0．02）×10^-3mm^2／s，志愿者（0．91±0．03）×10^-3mm^2，t=3．940，P〈0．001；脑白质：RNMO患者（0．82±0．02）×10^-3mm^2／s，志愿者（0．80±0．02）×10^-3mm^2／s，t=3．117，P=0．004；脑灰质：RNMO患者（1．06±0．04）×10^-3mm^2／s，志愿者（0．88±0．05）×10^-3mm^2／s，t=4．031，P〈0．001]、脑白质的FA直方图峰高抬高[RNMO患者（2．61±0．18）‰，志愿者（2．38±0．18）‰，t=3．627，P=0．001]及脑灰质的MD直方图峰高降低[RNMO患者（7．37±0．89）‰，志愿者（8．91±1．71）‰，t=3．210，P=0．003]和峰位置抬高[RNMO患者（0．83±0．02）×10^-3mm^2／s，志愿者（0．81±0．02）×10^-3mm^2／s，t=4．373，P〈0．001]；与脊髓和视神经有直接联系ROI的平均MD升高[延髓：RNMO患者（1．27±0．11）×10^-3mm^2／s，志愿者（1．11±0．10）×10^-3mm^2／s，t=4．260，P〈0．001；大脑脚：RNMO患者（1．01±0．11）×10^-3mm^2／s，志愿者（0．87±0．05）×10^-3mm^2／s，t=4．391，P〈0．001；内囊：RNMO患者（0．74±0．01）×10^-3mm^2／s，志愿者（0．72±0．01）×10^-3mm^2／s，t=4．683，P〈0．001；视放射：RNMO患者（0．88±0．03）×10^-3mm^2／s，志愿者（0．82±0．03）×10^-3mm^2／s，t=4．619，P〈0．001）、平均FA降低（延髓：RNMO患者0．27±0．01，志愿者0．29±0．03，t=2．996，P=0．005；大脑脚：RNMO患者0．49±0．04，志愿者0．54±0．03，t=4．280，P〈0．001；内囊：RNMO患者0．66±0．02，志愿者0．69±0．02，t=3．953，P〈0．001；视放射：RNMO患者0．53±0．04，志愿者0．59±0．03，t=4．705，P〈0．001）；而与脊髓和视神经无直接联系的胼胝体的平均MD[膝部：RNMO患者（0．76±0．04）×10^-3mm^2／s，志愿者（0．73±0．03）×10^-3mm^2／s；压部：RNMO患者（0．77±0．05）×10^-3mm^2／s，志愿者（0．73±0．04）×10^-3mm^2／s]和FA值（膝部：RNMO患者0．82±0．03，志愿者0．82±0．03；压部：RNMO患者0．83±0．03，志愿者0．83±0．02）差异无统计学意义（P值均〉0．005）。结论RNMO患者存在隐匿性脑组织损伤，这可能与继发于脊髓和视神经病灶的顺行和逆行性变性有关。     

Quantitative assessment of the cervical spinal cord damage in neuromyelitis optica using diffusion tensor imaging at 3 Tesla

Purpose:

To investigate whether quantitative MRI measures of cervical spinal cord white matter (WM) using diffusion tensor imaging (DTI) in neuromyelitis optica (NMO) differed from controls and correlated with clinical disability.

Materials and Methods:

Ten referred patients and 12 healthy volunteers were imaged on a 3 Tesla scanner and patients were clinically assessed on the Expanded Disability Status Scale (EDSS). Two raters quantified DTI‐derived indices from all participants, including fractional anisotropy (FA), mean diffusivity (MD), parallel diffusivity (lambda[parallel]) and perpendicular diffusivity (lambda[perpendicular]) at C1–C6 for lateral and dorsal columns. After the inter‐rater reliability test, univariate correlations between DTI measures and disability were assessed using the Spearman's rho correlation coefficient. Multiple regression analysis was performed to investigate which DTI measures independently correlated with the clinical score.

Results:

Statistical test results indicated high reliability of all DTI measurements between two raters. NMO patients showed reduced FA, increased MD and lambda[perpendicular] compared with controls while lambda[parallel] did not show any significant difference. The former three DTI metrics also showed significant correlations with disability scores, and especially FA was found to be sensitive to mild NMO (EDSS ≤ 3)

Conclusion:

FA is a potentially useful quantitative biomarker of otherwise normal appearing WM damage in NMO. Such damage is associated with clinical disability. J. Magn. Reson. Imaging 2011;33:1312–1320. © 2011 Wiley‐Liss, Inc.     

热射病患者看似正常的小脑扩散张量成像研究

热射病（heat stroke ,HS）是一种常发生于夏季热浪期的致命性急症,以高热（体温常＞40℃）和意识障碍为主要特征［1－2］,可伴发多器官功能受损,并发症包括急性呼吸窘迫综合征、代谢性酸中毒、电解质平衡紊乱、横纹肌溶解症、弥散性血管内凝血等［1］。以往研究表明小脑对热损伤极其敏感［3］,其神经病理学改变主要为小脑 Purkinje细胞的严重丢失［4］。扩散张量成像（diffusion tensor imaging ,DTI）可从微观上探测脑组织的水分子扩散异常［5］。本研究通过研究 HS患者小脑的DTI表现,旨在探讨其应用价值。     

急性一氧化碳中毒脑损伤的磁共振扩散张量成像

目的：利用磁共振扩散张量成像(DTI )评估急性一氧化碳(CO)中毒患者的脑结构损伤情况。方法25例急性(5.0 d±1.44 d) CO 中毒患者和37例性别、年龄、利手、受教育程度匹配的健康志愿者进行 DTI 扫描,获得扩散张量纤维束成像(DTT)图像,并分别测量双侧小脑半球(齿状核)、黑质、海马、额叶白质(侧脑室前角前下方、侧脑室体部上方)、尾状核头、苍白球、丘脑、内囊前肢、内囊后肢、枕叶白质(视中枢)、顶叶白质(侧脑室体部上方)及胼胝体膝部、压部共26个感兴趣(ROI)的各向异性分数(FA)值和表观扩散系数(ADC)值,进行组间配对 t 检验。结果病患组双侧苍白球、双侧内囊前肢、双侧黑质、右侧小脑、左侧额叶下部白质、右额叶上下部白质、胼胝体膝部的 FA 值显著低于对照组(P <0.05)。病患组右侧黑质、左侧苍白球的 ADC 值显著降低(P <0.05),病患组右额叶上下部白质及双侧枕叶白质 ADC 值显著升高(P <0.05)。结论急性 CO 中毒患者广泛脑微结构受损,提示脑微结构的原发损伤可能是 CO 中毒迟发性脑病潜在的病理生理基础。     

视神经脊髓炎患者视神经扩散张量成像研究

目的 探讨DTI在视神经脊髓炎(NMO)患者视神经病变中的诊断价值.方法 选取28例NMO患者和38名健康志愿者进行视神经DTI扫描,并对视神经眶内段前部、中部及后部进行各向异性分数(FA值)测量.将NMO患者根据视力是否受损及视觉诱发电位(VEP)是否异常分为单眼受累组(10只眼)、双眼受累组(36只眼)及看似正常组(10只眼),所有患者进行扩展残疾状况量表(EDSS)评分.采用单因素方差分析、ROC曲线分析及Spearman相关分析,对各组间FA值及FA值与病程、EDSS评分等的相关性进行分析.结果 各组间FA值比较差异有统计学意义(F=43.54,P＜0.01).其中,单眼受累组(0.29±0.08)、双眼受累组(0.27±0.08)及看似正常组视神经(0.35±0.13)FA值较正常对照组(0.45±0.07)减低,差异均有统计学意义(P值均＜0.01),双眼受累组FA值较看似正常组FA值减低(P＜0.01).ROC曲线分析显示正常对照组与单眼受累组、双眼受累组、看似正常组以及全部NMO患者组曲线下面积分别为0.92、0.95、0.74及0.91,其诊断视神经受损的敏感度分别为80％、86％、50％及79％,特异度均为95％.相关性分析显示FA值与NMO患者各组EDSS评分均无相关性,FA值与双眼受累组病程呈负相关(r=-0.371,P＜0.05).结论 NMO患者视神经均存在不同程度的损害,视神经DTI可以简单有效地定量评估NMO患者视神经的损害.     

Diffusion tensor imaging of patients with HIV and normal-appearing white matter on MR images of the brain

BACKGROUND AND PURPOSE: HIV enters the CNS early in the course of infection and produces neuropsychiatric impairment throughout the course of illness, which preferentially affects the subcortical white matter. The development of a neuroimaging marker of HIV may allow for the earliest detection of cognitive impairment. The purpose of this study was to determine whether MR diffusion tensor imaging can detect white matter abnormalities in patients who have tested positive for HIV. METHODS: Ten patients with HIV (eight men and two women; mean age, 42 years) underwent MR imaging of the brain with MR diffusion tensor imaging, which included routine fluid-attenuated inversion recovery and fast spin-echo T2-weighted imaging. Diffusion constants and anisotropy indices were calculated from diffusion tensor maps. Peripheral viral load, Centers for Disease Control staging, and cluster of differentiation 4 levels were determined. RESULTS: All patients had normal results of MR imaging of the brain, except for mild atrophy. Four of 10 patients had undetectable viral loads. These patients were receiving highly active antiretroviral therapy. The diffusion constant and anisotropy were normal. Four of 10 patients had viral loads between 10,000 and 200,000. Diffusion anisotropy in the splenium and genu was significantly decreased (P < .02). The diffusion constant of the subcortical white matter was elevated in the frontal and parietooccipital lobes (11%). Two of 10 patients had viral loads >400,000. Anisotropy of the splenium was half normal (P < .0004) and of the genu was decreased 25% (P < .002). The average diffusion constant was diffusely elevated in the subcortical white matter. CONCLUSION: Calculating the diffusion constant and anisotropy in the subcortical white matter and corpus callosum in patients with HIV detected abnormalities despite normal-appearing white matter on MR images and nonfocal neurologic examinations. Patients with the highest diffusion constant elevations and largest anisotropy decreases had the most advanced HIV disease. Patients with the lowest viral load levels, who had normal anisotropy and diffusion constants, were receiving highly active antiretroviral therapy.     

DTI及MRS在胶质母细胞瘤瘤周显示正常区的应用

目的 评价磁共振扩散张量成像(DTI)及2D多体素氢质子磁共振波谱成像技术(1H-MRS)在胶质母细胞瘤瘤周显示正常区中的应用价值.方法 对35例胶质母细胞瘤患者行常规MRI、DTI及1H-MRS检查,所有患者均行增强扫描.测量肿瘤瘤周显示正常区的ADC值、FA值、Cho/Cr、Cho/NAA、NAA/Cr的比值,并且计算相应区域NAA/nCr的比值,并与对侧正常区域的相应比值比较,分析其差异是否有统计学意义.结果 (1)瘤周显示正常区的ADC值略高于对侧,但差异无统计学意 义(P=0.195);瘤周显示正常区的FA值较对侧降低,差异有统计学意义(P<0.05);(2)瘤周显示正常区的Cho/Cr、Cho/NAA的比值较对侧明显升高,其差异有统计学意义(P<0.05);瘤周显示正常区NAA/Cr值较对侧亦有降低,但差异无统计学意义(P=0.177),NAA/nCr值较对侧明显降低,差异有统计学意义(P=0.023).结论 MRI扩散张量成像技术FA值的变化及2D多体素1H-MRS成像技术对肿瘤周围区代谢物变化的检测可以为推断胶质母细胞瘤瘤周区肿瘤细胞的浸润范围提供依据.     

多发性硬化及视神经脊髓炎患者颈髓的扩散张量成像定量研究

目的 运用3.0 T MR DTI技术探讨复发-缓解型多发性硬化(RRMS)患者及复发型视神经脊髓炎(RNMO)患者颈髓结构的改变,以及与临床评分的相关性.方法 应用3.0TMR对30例RRMS(MS组)、28例RNMO患者(NMO组)及20名健康志愿者(对照组)行颈髓DTI,分别测量C2 ～6颈髓中央灰质、右侧索、左侧索和后索等部位的平均扩散率(MD)和部分各向异性分数(FA),并对各测量值和扩展残疾状况量表(EDSS)评分进行相关性分析.统计学分析采用单因素方差分析及Spearman秩相关分析等.结果 (1)3组间MD值在C3水平后索和左侧索、C4水平中央灰质和后索、C5 ～6水平各部位差异具有统计学意义(F值为4.006 ～ 36.814,P值均＜0.05),3组间FA值在各层面差异均具有统计学意义(F值为5.561 ～98.128,P值均＜0.05).(2)MS组、NMO组和对照组两两比较:MS组、NMO组较对照组MD值升高,FA值降低,差异有统计学意义(t值为-0.320～3.138,P值均＜0.05);MS组和NMO组比较,MD值的差异无统计学意义(t值为-1.183 ～0.069,P值均＞0.05);NMO组在C4水平中央灰质、后索、右侧索、左侧索FA值分别为0.57±0.09、0.56±0.11、0.54±0.10、0.57±0.09,C5水平分别为0.55 ±0.11、0.52±0.13、0.55±0.11、0.54±0.13,C6水平分别为0.54±0.10、0.54 ±0.11、0.53 ±0.13、0.52 ±0.11;相对应MS组C4水平FA值为0.67 ±0.10、0.68±0.10、0.68 ±0.10、0.70±0.12,C5水平为0.68 ±0.11、0.69 ±0.10、0.68 ±0.11、0.69 ±0.12,C6水平为0.67±0.14、0.68 ±0.15、0.69±0.14、0.69±0.16,两组间C4 ～6水平FA值差异均有统计学意义(t值为-0.011 ～0.169,P值均＜0.05).(3)除C2及C4水平侧索外,其余各层面MD值同EDSS评分呈正相关(r值为0.324 ～0.541,P值均＜0.05),FA值同EDSS评分呈明显负相关(r值为-0.632 ～-0.294,p值均＜0.05).结论 DTI定量指标对颈髓的脱髓鞘病变敏感,在鉴别MS与NMO上具有潜在的应用价值;并可作为脱髓鞘病变临床监测的重要生物学指标.     

视神经脊髓炎脑部及脊髓影像学特征

目的探讨视神经脊髓炎(neuromyelitis optica,NMO)患者脑部及脊髓MRI影像学表现及特征。方法回顾性分析符合2006年Wingerchuk诊断标准23例NMO患者的脑部、脊髓MRI表现,分析NMO患者脑部及脊髓病灶的分布及信号特点。结果典型的NMO脑内病灶位于脑室室管膜下、下丘脑及脑干等部位,表现为斑点、斑片及线状异常信号。5例脑部增强检查均未见异常强化病灶。NMO患者脊髓常呈长节段横贯性或次横贯性损伤,且以脊髓中央灰质受累为主,可见线样征。结论 NMO患者脊髓及脑部MRI出现异常信号有较特异的好发部位,病灶的分布有其自身特征。     

Diffusion tensor imaging in multiple sclerosis: assessment of regional differences in the axial plane within normal-appearing cervical spinal cord

BACKGROUND AND PURPOSE: Evaluation of the spinal cord is important in the diagnosis and follow-up of patients with multiple sclerosis. Our purpose was to investigate diffusion tensor imaging (DTI) changes in different regions of normal-appearing spinal cord (NASC) in relapsing-remitting multiple sclerosis (RRMS). METHODS: Axial DTI of the cervical spinal cord was performed in 24 patients with RRMS and 24 age- and sex-matched control subjects. Fractional anisotropy (FA) and mean diffusivity (MD) were calculated in separate regions of interest (ROIs) in the anterior, lateral, and posterior spinal cord, bilaterally, and the central spinal cord, at the C2-C3 level. Patients and control subjects were compared with respect to FA and MD with the use of an exact Mann-Whitney test. Logistic regression and receiver operating characteristic (ROC) curve analysis assessed the utility of each measure for the diagnosis of RRMS. RESULTS: DTI metrics in areas of NASC in MS were significantly different in patients compared with control subjects; FA was lower in the lateral (mean +/- SD of 0.56 +/- 0.10 versus 0.69 +/- 0.09 in control subjects, P < .0001), posterior (0.52 +/- 0.11 versus 0.63 +/- 0.10, P < .0001), and central (0.53 +/- 0.10 versus 0.58 +/- 0.10, P = .049) NASC ROIs. Assessing DTI metrics in the diagnosis of MS, a sensitivity of 87.0% (95% confidence interval [CI], 66.4 to 97.1) and a specificity of 91.7% (95% CI, 73.0 to 98.7) were demonstrated. CONCLUSION: The NASC in RRMS demonstrates DTI changes. This may prove useful in detecting occult spinal cord pathology, predicting clinical course, and monitoring disease progression and therapeutic effect in MS.     

视神经脊髓炎视觉通路损害的影像研究

视神经脊髓炎（NMO）是以复发性炎性脱髓鞘为特征的中枢神经系统自身免疫性疾病,主要累及视神经和脊髓。视神经炎是NMO病人典型的临床表现之一,其视觉损害通常很严重且复发率高,预后很差。多项研究显示,NMO病人存在视觉通路多个部位广泛受累,而损伤机制目前仍不十分明确。NMO视觉通路的影像研究有助于对该病损伤机制的理解,现对NMO视觉通路的传统MRI、多种MRI新技术及光学相干断层成像等方面的研究进展予以综述。      

对视神经脊髓炎损害中脱髓鞘的作用:MR扩散张量成像的研究

目的检验-假说,即视神经脊髓炎的白质损害比先前描述的更广泛,其很可能包括表现正常的白质。应用扩散张量(DT)成像技术探究白质损害是否不仅与华勒氏变性有关,而且也可由脱髓鞘造成。材料与方法17例视神经脊髓炎病人(平均年龄45岁,14例为女性)与17名性别和年龄     

Diffusion tensor imaging of the developing mouse brain.

It is shown that diffusion tensor MR imaging (DTI) can discretely delineate the microstructure of white matter and gray matter in embryonic and early postnatal mouse brains based on the existence and orientation of ordered structures. This order was found not only in white matter but also in the cortical plate and the periventricular zone, which are precursors of the cerebral cortex. This DTI-based information could be used to accomplish the automated spatial definition of the cortical plate and various axonal tracts. The DTI studies also revealed a characteristic evolution of diffusion anisotropy in the cortex of the developing brain. This ability to detect changes in the organization of the brain during development will greatly enhance morphological studies of transgenic and knockout models of cortical dysfunction. Magn Reson Med 46:18-23, 2001.     

Analysis of brain and spinal cord lesions to occult brain damage in seropositive and seronegative neuromyelitis optica

ObjectivesAccording to aquaporin-4 antibody (AQP4-Ab), neuromyelitis optica (NMO) can be divided into seropositive and seronegative subgroups. The purpose of this study was to a) compare the distribution of spinal cord and brain magnetic resonance imaging (MRI) lesions between seropositive and seronegative NMO patients; b) explore occult brain damage in seropositive and seronegative NMO patients; and c) explore the contribution of visible lesions to occult grey and white matter damage in seropositive and seronegative NMO patients.Materials and methodsTwenty-two AQP4-Ab seropositive and 14 seronegative NMO patients and 30 healthy controls were included in the study. Two neuroradiologists independently measured the brain lesion volume (BLV) and the length of spinal cord lesion (LSCL) and recorded the region of brain lesions. The normal-appearing grey matter volume (NAGM-GMV) and white matter fractional anisotropy (NAWM-FA) were calculated for each subject to evaluate occult brain damage.ResultsThe seropositive patients displayed more extensive damage in the spinal cord than the seronegative patients, and the seronegative group had a higher proportion of patients with brainstem lesions (28.57%) than the seropositive group (4.55%, P = 0.064). Both NMO subgroups exhibited reduced NAGM-GMV and NAWM-FA compared with the healthy controls. NAGM-GMV was negatively correlated with LSCL in the seropositive group (r_s = −0.444, P = 0.044) and with BLV in the seronegative group (r_s = −0.768, P = 0.002). NAWM-FA was also negatively correlated with BLV in the seropositive group (r_s = −0.682, P < 0.001).ConclusionOur findings suggest that the occult brain damage in these two NMO subgroups may be due to different mechanisms, which need to be further clarified.     

Diffusion tensor MR imaging of the brain. Clinical applications

Diffusion tensor MR imaging is a technique that provides details on tIssue microstructure and organization well beyond the usual image resolution. With diffusion tensor MR imaging, diffusion anisotropy can be quantified and subtle white matter changes not normally seen on conventional MRI can be detected. The purpose of this article is to review the current applications of diffusion tensor MR imaging for the study of the brain, including normal aging, Alzheimer's disease, neuropsychiatric disorders, strokes, multiple sclerosis, brain tumors and intractable seizures.