磁共振脑灰白质成像在脑灰质异位症中的临床应用

目的：探讨磁共振脑灰白质成像在脑灰质异位症中的诊断价值。方法：回顾性分析5例经临床及MRI检查确诊的脑灰质异位症患者，全部患者均行脑MRI常规T1WI、T2WI序列、FLAIR序列和脑灰白质成像检查。结果：5例脑灰质异位症患者在MRI各扫描序列上病灶信号与脑灰质信号完全相同，特别是在脑灰白质成像上对异位的灰质灶观察更为满意，更有利于判断病变的性质。结论：脑灰白质成像在观察灰质异位方面有独到价值，在分析癫痫病因方面可提供更直接的影像学信息。对于脑灰质异位症患者，脑灰白质成像对于帮助发现病灶并判断其性质甚为必要，是对常规序列的必要补充，具有较高的临床应用价值。     

儿童后部可逆性脑病综合征的CT及MRI表现

目的 探讨儿童后部可逆性脑病综合征(PRES)的CT及MRI表现.资料与方法 搜集本院患儿资料8例,男7例,女1例,其中淋巴瘤化疗患儿、急性肾炎和肾病综合征各2例,紫癜肾和急性肾功能衰竭各1例.其中,5例肾病患儿血压升高.8例患儿行MRI扫描,包括T1WI、T2WI、液体衰减反转恢复序列(FLAIR)成像及扩散加权成像(DWI),其中1例间时行增强MR及MR血管威像(MRA),1例行MRA和MR静脉血管成像(MRV);其中4例行CT平扫.结果 MRI及CT显示双侧顶枕叶(8例)、额叶(2例)、颞叶(1例)、基底节区(1例)及左脑半球(1例)多发异常信号或低密度,主要位于双侧顶枕叶皮质及皮质下自质内,6例患儿皮质受累.在T1WI上病灶呈等或略低信号,T2WI及FLAIR上呈高信号,以FLAIR像显示皮质病变为佳.DWI显示大部分病灶呈等信号,表观扩散系数(ADC)图呈等或高信号.部分病灶DWI表现为高信号.1例行MR增强扫描患儿显示病灶部位沿脑膜斑片状及线样强化,皮层下脑组织内病变呈片状强化.2例MRA及1例MRV各大动脉血管及静脉窦未见明显狭窄、扩张或栓塞征象.随访MRI及CT显示所有患儿病灶范围逐渐缩小,数目减少.结论 FRES好发于顶枕叶皮层及皮层下白质,病变大部分为血管源性水肿,增强T1WI示病灶有强化.儿童与成人病变影像学表现及临床特点有所不同.MRI是PRES的主要检查方法.     

ESWAN序列在脑膜瘤成像中的应用价值初探

目的初步探讨增强T2*加权血管成像(enhanced T2star weighted angiography,ESWAN)序列在脑膜瘤成像中的价值。方法搜集于我院进行术前检查的临床病理及影像资料完整的脑膜瘤患者11例,女9例,男2例,年龄25～68岁,平均51岁。采用GE 3.0 T MR扫描仪(Signa),8通道头部表面线圈,扫描序列包括常规T1WI、增强T1WI、T2WI、T2液体衰减反转恢复序列(FLAIR)和ESWAN序列。将ESWAN与常规MRI序列图像进行对比分析。结果 11例脑膜瘤中7例ESWAN较清楚地显示了肿瘤的血管结构,5例较清楚地显示了肿瘤的出血灶,1例较清楚地显示了钙化灶。结论 ESWAN较常规MRI序列可以更好地显示脑膜瘤的血管结构、出血灶及钙化,可作为脑膜瘤常规MRI检查的重要补充序列,有利于对不典型病变的诊断与鉴别诊断,可对脑膜瘤的术前诊断提供更全面、精确的信息。     

脑灰质异位症的临床及影像学诊断

目的探讨脑灰质异位症(GMH)的临床表现及影像诊断价值。方法选取并分析83例GMH临床及影像学表现。结果临床表现为癫痫发作46例,智力落后伴癫痫12例,头晕头痛4例,胎儿期发现异常6例。CT平扫5例,MRI检查59例(增强12例),CT及MRI均检查19例(增强7例)。室管膜下、白质内、带状及混合性GMH病例数分别为60、4、3及16例。表现为相应部位单发或多发,异常结节样、团块状或带状灰质密度或信号。主要合并症为侧脑室扩大、大枕大池、蛛网膜囊肿、脑裂畸形、皮层发育不良、脑软化及腔隙灶,胼胝体发育不良、静脉畸形及颅缝早闭等。合并症≥2项者33例,不伴合并症16例。结论 GMH主要临床表现以全身阵挛强直癫痫为主。MRI平扫T1WI、T2WI及DWI序列,即可进行GMH范围及分布的明确诊断,3D薄层T1WI及重建可为诊断及手术治疗者提供更全面影像信息。     

脑灰质异位症MRI诊断

目的探讨脑灰质异位症(GMH)的MR I诊断及鉴别诊断。方法10例GMH患者均行MR回波序列扫描,其中男7例,女3例,年龄7~32岁,平均15岁。1例行MR增强扫描。结果10例共发现病灶14个,分为3种类型:室管膜下型5例、皮质下型3例、带状型2例。表现为侧脑室旁或白质区内的结节状或不规则状团块影,与大脑皮层灰质及灰质核团信号一致,单发7例、多发3例,单侧发病8例,双侧发病2例,大小1~5 cm不等,无水肿及占位效应,2例带状型灰质异位对称分布于皮层灰质与侧脑室间,内外均有白质带,与灰质信号一致。结论GMH的MR I表现具有特异性。     

结节性硬化症的CT和MRI特点

目的:分析结节性硬化症颅内结节分布特征;比较磁共振T2WI与FLAIR序列对颅内结节的显示能力.方法:计数40例患者各个脑叶结节数量,用SPSS 11.5软件比较颅内结节在各脑叶的数量差异;Siemens Trio 3.0T核磁共振仪扫描其中16例, 测量T2WI和FLAIR未钙化结节总体积,比较二者差异.结果:CT和MRI显示本组患者均存在室管膜下结节,MRI显示85%患者存在皮层及皮层下结节;χ2检验P(双侧)=0.49,表明结节在各脑叶数量无差异;配对T检验P(双侧)=0.001,表明T2WI与FLAIR测得结节总体积具有显著差异.结论:结节在各脑叶的数量无差异;FLAIR比T2WI更能敏感检出结节.     

椎间盘源性下腰痛患者脑灰质体积改变的MRI研究

【摘要】目的：采用MR基于体素的形态学测量（VBM）技术,探讨椎间盘源性下腰痛患者大脑灰质体积的变化。方法：2016年5月-10月对本院22例椎间盘源性下腰痛患者和22例健康志愿者行3.0T MRI扫描,扫描序列包括T1WI、T2WI和三维快速扰相梯度回波序列T1WI,经图像后处理及统计分析,获得两组受试者大脑灰质形态学差异的相关信息。结果：与对照组比较,下腰痛组患者大脑皮层多个脑区灰质体积减少,包括右侧额上回、左侧额内侧回、左侧直回、右侧颞上回、右侧颞中回、右侧岛叶以及右侧额下回（P＜0.001,FWEc校正）;无灰质体积增加的区域。结论：慢性椎间盘源性下腰痛可引起广泛的脑功能区灰质体积的减少,这些脑区主要涉及感觉、认知及情绪,一定程度上揭示了慢性椎间盘源性下腰痛神经系统病变的发生机制。     

液体衰减反转恢复序列MR成像在颅脑创伤诊断中价值的研究

目的评价MR液体衰减反转恢复序列(fluid-attenuated inversion recovery,FLAIR)诊断各种颅脑创伤病变的价值.方法22例颅脑创伤病例均进行了CT和MR T1WI、T2WI及FLAIR序列检查,CT与MR检查的时间间隔为4.6±3.7天.观察CT与三种MR序列上各种病变病灶的显示数,将FLAIR所见的结果分别与CT、T1WI及T2WI结果作统计学分析(t检验).结果22例共有100个颅内创伤病灶,CT检出率为25%,T1WI为49%,T2WI为71%,FLAIR检出率为100%,差异显著(P<0.0005).其中FLAIR对非出血性脑挫伤的显示效果最佳,优于其它三种技术(P<0.0005);对于出血性挫伤,FLAIR优于CT(P<0.0025),但与T1WI及T2WI无明显差别;FLAIR对硬膜下/硬膜外血肿的发现能力与其它三种技术相似,对硬膜下积液的显示优于CT(P<0.0025),与T1WI及T2WI则无显著差异;FLAIR对亚急性期的蛛网膜下腔出血(SAH)的显示能力超过CT和T2WI(P<0.05),但CT与FLAIR对急性SAH的显示能力一致.结论FLAIR序列能明显地改善颅脑创伤性病变的显示,优于CT和常规MRI技术,其中以非出血性挫伤和亚急性期的SAH效果最佳.FLAIR序列可作为颅脑创伤检查的常规手段.     

对比T2FLAIR序列与增强T1WI序列在诊断脑转移瘤过程中的诊断价值

目的：比较增强T1WI及增强T2FLAIR两种序列对脑转移瘤的诊断价值。方法：回顾分析本院2008年9月～2010年3月34例经临床和影像检查确诊为脑转移瘤的患者资料,所有病例均行常规MRI平扫及SET1WI和T2FLAIR增强扫描,比较两种序列上转移瘤的数目、大小和部位以及转移瘤的强化显著性、病变强化区的边界等,并分析两者间偏差的原因。结果：34个病例,MRI平扫共检出129个病灶,增强T1WI发现194个病灶,而增强后T2WI FLAIR共发现185个病灶,4例增强后T2FLAIR较增强后T1WI显示的病灶多,6例增强后T2FLAIR显示的病灶少于增强后T1WI,25例两者显示的病灶相同,增强后T1WI因为脑浅表层血管混淆而漏诊误诊7个病灶,在对比增强后T2FLAIR均可明确诊断。大多数转移瘤在T1WI的强化程度高于T2FLAIR序列。转移瘤的肿瘤与灰质、肿瘤与白质的CR（对比率）以FLAIR序列为高,而转移瘤的肿瘤与灰质、肿瘤与白质的CNR（对比噪声比）以T1WI为高,两者有显著性差异（P〈0.01）。结论：增强后T2FLAIR序列可以有效显示脑转移灶,很好地鉴别大脑浅表部位的血管和转移瘤,增强T1WI序列能更明显地显示转移瘤的强化,两者同时使用,可以提高转移瘤的检出率与诊断准确性。     

FLAIR序列在低场脑MRI中的应用研究

目的 :探讨在低场MRI中FLAIR序列对颅脑疾病的临床应用价值。方法 :2 4 7例颅脑疾病患者 ,均进行FLAIR序列和FSE T2 WI检查 ,比较两种序列对病灶的显示能力。结果 :MRI共发现 5 1 6个病灶 ,FLAIR序列显示病灶 5 0 8个(98 4 4%) ,FSE T2 WI显示病灶 4 36个 (84 .5 0 %) ,两者在显示病变方面有显著差异 (P <0 .0 1 )。FLAIR序列显示病灶内部结构及边缘良好者为 2 80个 (5 5 .1 2 %) ,FSE T2 WI为 1 2 0个 (2 7.5 2 %) ,两者在显示病变内部结构及边缘清晰度方面 ,FLAIR序列优于FSE T2 WI(P <0 .0 1 )。结论 :在低场脑MR中 ,FLAIR技术对颅脑病变的显示优于常规FSE T2 WI,有助于提高病变的检出率 ,清晰显示病灶内部结构与边缘 ,可作为颅脑MRI检查的常规序列。     

Gray matter and white matter abnormalities in online game addiction

Online game addiction (OGA) has attracted greater attention as a serious public mental health issue. However, there are only a few brain magnetic resonance imaging studies on brain structure about OGA. In the current study, we used voxel-based morphometry (VBM) analysis and tract-based spatial statistics (TBSS) to investigate the microstructural changes in OGA and assessed the relationship between these morphology changes and the Young's Internet Addiction Scale (YIAS) scores within the OGA group. Compared with healthy subjects, OGA individuals showed significant gray matter atrophy in the right orbitofrontal cortex, bilateral insula, and right supplementary motor area. According to TBSS analysis, OGA subjects had significantly reduced FA in the right genu of corpus callosum, bilateral frontal lobe white matter, and right external capsule. Gray matter volumes (GMV) of the right orbitofrontal cortex, bilateral insula and FA values of the right external capsule were significantly positively correlated with the YIAS scores in the OGA subjects. Our findings suggested that microstructure abnormalities of gray and white matter were present in OGA subjects. This finding may provide more insights into the understanding of the underlying neural mechanisms of OGA.     

Impact of white matter hyperintensities on surrounding white matter tracts

Purpose

It is unclear how white matter hyperintensities disrupt surrounding white matter tracts. The aim of this tractography study was to determine the spatial relationship between diffusion characteristics along white matter tracts and the distance from white matter hyperintensities.

Methods

Diffusion tensor 3-T MRI scans were acquired in 29 participants with white matter hyperintensities. In each subject, tractography by the fiber assignment by continuous tracking method was used to segment corticospinal tracts. Mean diffusivity, radial diffusivity, axial diffusivity, and fractional anisotropy were measured along corticospinal tracts in relation to white matter hyperintensities. Diffusion characteristics along tracts were correlated with distance from white matter hyperintensities and were also compared between tracts traversing and not traversing white matter hyperintensities.

Results

In tracts not traversing through white matter hyperintensities, increasing distance from white matter hyperintensities was associated with decreased mean diffusivity (p?=?0.002) and increased fractional anisotropy (p?=?0.006). In tracts traversing white matter hyperintensities, compared to tracts not traversing white matter hyperintensites, the mean diffusivity was higher at 6–8 voxels, axial diffusivity higher at 4–8 voxels, and radial diffusivity higher at 7 voxels away from white matter hyperintensities (all p?<?0.006).

Conclusion

White matter hyperintensities are associated with two patterns of altered diffusion characteristics in the surrounding white matter tract network. Diffusion characteristics along white matter tracts improve further away from white matter hyperintensities suggestive of a local penumbra pattern. Also, altered diffusion extends further along tracts traversing white matter hyperintensities suggestive of a Wallerian-type degenerative pattern.

     

Method for combining information from white matter fiber tracking and gray matter parcellation

We introduce a method for combining fiber tracking from diffusion-tensor (DT) imaging with cortical gray matter parcellation from structural high-spatial-resolution 3D spoiled gradient-recalled acquisition in the steady state images. We applied this method to a tumor case to determine the impact of the tumor on white matter architecture. We conclude that this new method for combining structural and DT imaging data is useful for understanding cortical connectivity and the localization of fiber tracts and their relationship with cortical anatomy and brain abnormalities.