恶性肿瘤脑膜转移的MRI表现及强化模式

目的：分析系统性恶性肿瘤脑膜转移的MRI表现，探讨脑膜强化对脑膜转移的诊断及鉴别诊断价值。方法：根据临床恶性肿瘤病史、脑脊液及病理检查确诊的脑膜转移瘤12例，其中原发肿瘤肺癌5例，乳腺癌3例，黑色素瘤1例，淋巴瘤2例，原发肿瘤不明1例。MR常规扫描后均行钆喷替酸葡甲胺(Gd—DTPA)增强扫描。结果：①MR平扫：异常脑膜改变仅2例，表现为沿软脑膜分布的多发结节；②MR增强扫描：12例呈3种脑膜强化模式，硬脑膜强化模式(硬脑膜～蛛网膜强化)3例，软脑膜强化模式(蛛网膜下腔一软脑膜强化)6例，全脑膜强化模式(硬脑膜、蛛网膜及软脑膜均强化)3例，其中2例表现为沿软脑膜分布的多发结节，10例表现为线样弥漫性脑膜强化；③其它征象：脑内转移3例，脑积水3例。结论：恶性肿瘤脑膜转移在MR增强扫描上可以表现为3种脑膜强化模式，其中软脑膜强化模式多见，结节性脑膜强化及脑内转移具有特异性。     

广州管圆线虫病中枢神经系统受侵的磁共振影像研究

目的：研究中枢神经系统广州管圆线虫病的磁共振影像表现。方法：５例经实验室检查和临床治疗证实的广州管圆线虫病患者共做头部及颈腰部ＭＲＩ检查１７例次。ＭＲＩ扫描仪为０．５Ｔ超导装置。在ＭＲＩ不同序列上观察脑、脊髓、脑脊膜和神经根有无病变及其分布、形态及信号表现,通过随访ＭＲＩ检查,分析病变出现及消散、好转情况。结果：５例患者ＭＲＩ显示脑膜脑炎３例,脑炎１例,脊髓脊膜炎１例。具体病变部位及表现如下：（１）脑实质累４例,脊髓１例。这些病变呈弥漫或散在分布,在Ｔ１ＷＩ上呈稍低或等信号,在Ｔ２ＷＩ和对应层面液体衰减反转恢复序列（ＦＬＡＩＲ）图像上呈高信号,注射钆喷替酸葡甲铵（Gd-DTPA）后病变中央可见圆形或卵圆形强化灶,最大直径１０mm。有时可见粗细不等的长条形强化,长达１４mm。强化灶周围可有小范围的低信号水肿区。（２）脑脊膜受累４例,其中包括室管膜及神经根受累各１例。注射Gd-DTPA后表现为软脑膜或（和）室管膜呈线条形或结节状强化及神经根强化。（３）轻度脑室扩张２例。追踪动态观察提示,发病后第５～８周是颅内病变最明显的时期,病变从发现至消退至少需要８周时间。结论：中枢神经系统广州管圆线虫病的ＭＲＩ表现多种多样。脑脊髓内多发长条形或结节状强化和软脑膜强化是本病主要的ＭＲＩ表现。     

颅脑血管外皮细胞瘤的CT、MRI与病理对照研究

目的：探讨颅脑血管外皮细胞瘤的临床、病理和ＣＴ、ＭＲＩ特征。材料与方法：收集经ＣＴ和ＭＲＩ诊断为脑膜瘤,经手术病理证实为血管外皮细胞瘤１２例,年龄３４￣５８岁。ＣＴ检查７例,均采用增强前、后常规扫描。ＭＲＩ检查１２例,采用ＳＥ序列增强前、后扫描。结果：１２例肿瘤全部发生在颅内脑外,７例ＣＴ平扫呈低等混合密度２例,呈等高混合密度５例;增强后扫描呈不均匀强化６例,均匀强化１例。骨窗显示病灶局部侵蚀性骨质破坏４例。ＭＲＩ平扫,Ｔ１ＷＩ呈等高不均匀信号１０例,呈等信号２例;Ｔ２ＷＩ呈不均匀等高信号１０例,呈等信号２例。１２例中７例显示脑膜尾征;增强后扫描１ 均呈不均匀强化。结论：血管外皮细胞瘤具有一定的ＣＴ、ＭＲＩ特征性表现：分叶状、丰富的血管流空、肿瘤内密度或信号不均匀、无肿瘤内钙化和骨质增生、局部颅骨呈溶骨性破坏。     

胼胝体变性的CT和MRI分析

分析胼胝体变性的ＣＴ和ＭＲＩ征象。材料与方法：４例胼胝体变性中，３例为急性发病，１例呈慢性过程，４例均头颅ＣＴ扫描，２例行ＭＲＩ检查，其中１例同行ＭＲＩ增强扫描。结果２例ＣＴ示胼胝体膝部和压部呈片状低密度病变，２例病变仅见于膝部。病变的膝部（３例）和压部（２例）呈膨胀性改变，其中１例发病１６天后，ＭＲＩ平扫和强化未见膨胀性改变和异常强化。结果：（１）ＣＴ和ＭＲＩ是诊断胼胝体变性的有效方法，ＭＲＩ显     

努力提高脑膜病变的影像诊断水平

脑膜包括硬脑膜、蛛网膜和软脑膜 ,看似简单 ,实际上其结构错综复杂。临床上很多疾病可累及脑膜 ,而脑膜本身也有许多原发病变 ,不同的病变可累及脑膜的不同部位。世界卫生组织 (ＷＨＯ) 1993年制定的中枢神经系统肿瘤的组织分类中 ,将脑 (脊 )膜肿瘤单独列为一类 ,其重要性可见一斑。ＣＴ和ＭＲＩ的出现 ,是 2 0世纪影像医学的两次重大变革 ,对人类医学的发展起到了巨大的推进作用。但自ＣＴ、ＭＲＩ问世以来 ,始终面临着如何正确诊断脑膜病变的严峻挑战 ,脑膜病变也始终是影像学诊断的难点、重点。近年来国内外诸多学者经过不懈的努力 ,在…     

脑原发性恶性淋巴瘤和CT和MRI诊断

目的 为提高对脑原发性恶性淋巴瘤的认识和ＣＴ、ＭＲＩ诊断水平、材料和方法 收集经病理证实的脑原发性恶性淋巴瘤１０例,其中ＣＴ检查７例、ＭＲＩ检查６例,结果 １０例病人中检出１３个病灶,ＣＴ和ＭＲＩ所见肿瘤形态不规则,其中１０个病灶有明显水肿。ＭＲＩ对原发性恶性淋巴瘤的检出率比ＣＴ更有效,ＭＲＩ示大部分病灶Ｔ１ＷＩ呈低信号,Ｔ２ＷＩ呈高信号。结论 分析了ＣＴ和ＭＲＩ的原因后,认为ＭＲＩ应作为脑原发性     

脑原发性恶性淋巴瘤的CT和MRI诊断

目的　为提高对脑原发性恶性淋巴瘤的认识和ＣＴ、ＭＲＩ诊断水平。材料和方法　收集经病理证实的脑原发性恶性淋巴瘤１０例,其中ＣＴ检查７例,ＭＲＩ检查６例。结果　１０例病人中检出１３个病灶,ＣＴ和ＭＲＩ所见肿瘤形态不规则,其中１０个病灶有明显水肿。ＭＲＩ对原发性恶性淋巴瘤的检出率比ＣＴ更有效、ＭＲＩ示大部分病灶Ｔ_１ＷＩ呈低信号、Ｔ_２ＷＩ呈高信号。结论　分析了ＣＴ和ＭＲＩ误诊的原因后,认为ＭＲＩ应作为脑原发性恶性淋巴瘤的首选检查方法。     

腹膜后纤维化的CT、MRI表现

目的：研究腹膜后纤维化的ＣＴ、ＭＲＩ表现。方法：本组经临床病理证实病例８例,其中男５例、女３例,平均年龄４８．０岁。特发性６例,非特发性２例。８例全部进行了ＣＴ扫描,其中２例作了强化扫描,１例进行了ＭＲＩ扫描。结果：８例中病变呈弥漫性３例,肿块性５例。ＣＴ平扫可呈低密度、不均匀密度或等密度,增强扫描显示不同程度强化。ＭＲＩ、Ｔ１ＷＩ、Ｔ２ＷＩ呈低信号强度。结论：本病为一种ＣＴ扫描表现多变的少见疾病,如腹膜后出现弥漫或肿块样病变合并肾及输尿管积水时应考虑到本病诊断。     

脑膜病变的MRI诊断及进展

与ＣＴ相比 ,ＭＲＩ尤其是增强ＭＲＩ,对脑膜及其病变的显示具有明显的优势[1 3] 。特别是近年来 ,由于设备的改进和软件的开发更新 ,作为诊断脑膜病变的主要影像检查手段的ＭＲＩ,其价值日益为临床医师所重视。ＭＲ成像技术脑膜由硬脑膜、蛛网膜和软脑膜组成。硬脑膜又分为外膜层 (即颅骨内板的骨膜 )和内膜层。软脑膜与蛛网膜统称为柔脑膜 (ｌｅｐｔｏｍｅｎｉｎｇｅｓ)。在脑底部 ,软脑膜和蛛网膜广泛分离形成基底池。自ＭＲ问世以来 ,应用最广泛、最可靠的序列是ＳＥ序列 ,但非增强ＳＥ序列显示脑膜并不敏感[1] 。正常脑膜表现为非连续…     

非脑膜瘤脑膜异常强化的MRI与病因对比研究

目的：分析不同脑膜病变的强化特征，探讨脑膜强化形式与病因诊断的关系。材料与方法：回顾性分析资料完整的异常脑膜强化２６例，根据脑膜受累层次、范围将强化形式分为四种：（１）弥漫性脑膜强化；（２）弥漫性硬膜强化；（３）弥漫性软膜强化；（４）局限性硬膜强化。依病因不同将脑膜病变分为三组：（１）肿瘤组；（２）炎症组；（３）反应组。结果：２６例中，肿瘤组８例，其中弥漫性硬膜、软膜强化各３例，弥漫性脑膜强化、局限性硬膜强化各１例。炎症组８例，弥漫性软膜强化７例，局限性硬膜强化１例。反应组１０例，８例呈局限性硬膜强化，２例呈弥漫性硬膜强化。结论：不同的脑膜病变可表现不同的强化特征，但离开临床，仅根据强化特征尚难做出定性诊断。     

Correlation of MRI and clinical features in meningeal carcinomatosis

Ten patients with meningeal carcinomatosis associated with nonhaemoatological neoplasms were examined: six with breast, two with gastrointestinal and one with lung cancer, plus one with a tumour of unknown origin. Cytology was positive in all but one. The patients were classified into four groups according to the gadolinium-enhanced MRI (Gd-MRI) appearances: group 1 had pure leptomeningeal carcinomatosis, group 2 dural carcinomatosis, group 3 spinal leptomeningeal carcinomatosis, and group 4 had normal Gd-MRI except for hydrocephalus. In group 1, Gd-MRI showed diffuse enhancement of the subarachnoid space, including the cisterns around the midbrain, the sylvian fissures, or cerebellaar and cerebral sulci. In group 2, Gd-MRI showed diffuse, thick, partially nodular enhancement of the duramater. No leptomeningeal or subependymal enhancement was evident. In group 3, nodular masses were seen only in the spinal canal. In group 4, no definite evidence of meningeal carcinomatosis was demonstrated on contrast-enhanced CT (CE-CT) or Gd-MRI. The median suvival time was 2.0 months in group 1, 1.0 month in group 3, and 4.5 months in group 4, but the two patients in group 2 were alive 10 and 15 months after a definite diagnosis of meningeal carcinomatosis was made. In all patients examined by both CE-CT and Gd-MRI, the latter was superior for identification of meningeal carcinomatosis. Hydrocephalus in an important indirect sign of leptomeningeal carcinomatosis, but was not seen in patients with dural carcinomatosis despite the presence of increased intracranial pressure.     

肝脏原发性神经内分泌肿瘤影像学表现及病理对照

目的 探讨肝脏原发性神经内分泌肿瘤(PHNET)的CT、MRI表现及其病理基础.方法 收集经手术病理证实的PHNET 14例(14例均行CT检查,其中9例行MR检查),分析病灶的CT、MRI表现,探讨形成影像表现的病例基础.结果 PHNET呈单发(8例)或多发结节(5例),弥漫性全肝分布1例.CT平扫呈低密度,1例可见液-液平面病理为内部出血;动脉期呈结节状或环形强化,1例呈弥漫性强化,门静脉期或延迟期强化减低.MRI呈长T1长T2信号,出血呈短T1短T2信号,强化形式与CT相同.随病理分级的提高,病灶由G1单发实性-G2实性或囊实性-G3弥漫性分布或出现肝内转移.扩散加权成像(DWI)呈扩散受限改变.结论 CT、MRI能够显示出PHNET的影像学特殊表现和组织学特征.     

Primary diffuse meningeal melanomatosis: radiologic-pathologic correlation

We report a case of primary diffuse meningeal melanomatosis, a rare variant of primary malignant melanoma of the CNS, in a 68-year-old woman. The disease mimicked intracranial hypotension syndrome and was diagnosed only at autopsy (CSF cytologic results were negative). CT revealed hydrocephalus with effacement of the cerebral convexity sulci and abnormal contrast enhancement in the right sylvian and frontoparietal fissures, whereas MR imaging showed diffuse marked dural and leptomeningeal contrast enhancement. In retrospect, these nonspecific findings correlated with the extensive leptomeningeal invasion in the cerebral hemispheres, brain stem and spinal cord. The clinical, radiologic, and pathologic features of diffuse meningeal melanomatosis are reviewed.     

颅内结核性脑膜炎的MRI诊断

目的 评估ＭＲＩ对颅内结核性脑膜炎的诊断价值。材料与方法 对１８例颅内结核怀脑膜炎的ＭＲＩ表现、Ｇｄ－ＤＴＰＡ增强的作用和追踪ＭＲＩ的变化进行分析。结果 ＭＲＩ显示脑膜炎１３例,表现为蛛网膜腔狭窄和消失,脑脊液分房。在增强ＭＲＩ上,受累的脑膜呈线形、弥漫性斑块和结节状或环状显著性强化。结核性脑膜炎合并结核瘤２例,结核性脑脓肿２例,脑梗塞１例。结论 结核性脑膜炎的ＭＲＩ表现有一定的特点,增强ＭＲＩ可     

脑灰质异位的CT及MRI诊断

目的:分析脑灰质异位(HGM)的CT及MRI表现,加深对本病的认识,减少漏诊及误诊的分生。方法:搜集我院经临床、CT和/或MRI证实的HGM17例,CT检查9例,MRI检合5例,CT MRI检查3例,回顾性分析其影像学表现。结果:17例中,单侧12例(左侧8例,右侧4例),其中室管膜下结节型3例,混合型桥带型5例,非室管膜下结节型4例。非室管膜下结节型均为单发,额顶叶、颞顶叶、顶枕叶及半卵圆中心各1例:双侧5例,室管膜下结节型2例,其中1例合并胼胝体发育不全;室管膜下弥漫型2例,其中1例合并四叠体池及枕大池蛛网膜囊肿;非室管膜下弥漫性1例。上述病灶位于脑白质内、侧脑室室管膜下或两省均有,呈结节、团块或条带状,在CT及MRI各序列上均与脑灰质密度或信号相同。结论:HGM在CT及MRI上具有特征性的影像学表现,因MRI为多参数成像,在对不典型及小HGM的检出优于CT。     

脑血吸虫病的CT与MRI诊断对比研究

目的：研究脑血吸虫病的CT、MRI表现，并探讨两种检查方法对该病的诊断价值。方法：本组28例患者均同时行CT、MRI检查(平扫 增强)，分析该病的影像学征象并结合9例手术病理资料进行对比。结果：27例有不同程度的水肿；22例呈水肿伴不规则结节，增强后呈结节状、斑片状及融合成簇状强化；CT发现54个病灶．MRI发现75个病灶。结论：脑血吸虫病在CT及MRI增强扫描中都具有特异性表现，MRI信号更接近其病理改变；两种检查方法郜具有重要的临床价值，但MRI明显优于CT。     

软脑膜异常强化的MRI表现及其诊断价值

目的:分析不同性质软脑膜病变的MRI表现,探讨其诊断价值。方法:回顾性分析38例软脑膜病变的增强MRI表现,其中软脑膜转移17例,感染性脑膜炎15例,脑梗塞5例,Sturge-Weber综合症1例,所有病例均经手术、临床和实验室检查证实。结果:软脑膜转移中结节样强化12例、弥漫对称性细线样强化12例,其中7例二者并存,未见粗线样或局灶性强化,除5例脑内伴转移瘤所致脑实质异常外,其余12例脑实质未见异常;感染性脑膜炎中线样强化14例,其中细线样及粗线样强化各7例,1例粗线样强化伴结节样强化,局限性、弥漫性强化分别为8例和7例,软脑膜邻近脑实质单纯性水肿者8例;脑梗塞中5例均表现为梗塞灶邻近软脑膜细线样强化,1例Sturge-Weber综合症表现为软脑膜粗线样强化,邻近脑实质萎缩。结论:MRI是检出软脑膜病变敏感和有效的方法,不同性质病变的软脑膜强化具有一定的特点,可为临床诊断、鉴别诊断和治疗提供线索。     

MR imaging of the cranial meninges with emphasis on contrast enhancement and meningeal carcinomatosis

MR imaging was used to investigate normal and abnormal meningeal enhancement, with an emphasis on meningeal carcinomatosis. Three groups of patients were studied on a 1.5-T system. In group 1, the normal meninges were examined in 20 patients and were found to show fine linear enhancement in short segments, especially in a parasagittal distribution. In group 2, all gadolinium-enhanced head scans were reviewed retrospectively. Abnormal meningeal enhancement was detected in 52 patients. In some of these, the enhancement was associated with pathologic conditions of the meninges, including leptomeningeal tumor and meningeal infections and other inflammatory conditions; in others the enhancement was adjacent to subdural hematomas, subacute infarcts, and skull lesions, such as metastases or postoperative defects. In group 3, 30 cases of meningeal carcinomatosis were studied prospectively. Enhancement was seen in approximately two-thirds of cases and usually was quite diffuse and applied to the inner table of the skull. Frank nodules were seen less often. Contrast-enhanced CT was equal to MR in the detection of nodules but was nearly always unable to show diffuse meningeal enhancement against the inner table of the skull. Contrast-enhanced MR was more sensitive than contrast-enhanced CT in the examination of normal and abnormal meninges. Abnormal findings, such as meningeal carcinomatosis, were demonstrated more often by MR than by CT.     

颅内生殖细胞瘤转移的MRI表现

目的　探讨颅内生殖细胞瘤转移的MR影像学表现 ,为临床治疗方案的选择提供影像学依据。方法　结合文献资料 ,对10例具有转移灶的颅内生殖细胞瘤患者的临床与MRI资料进行分析。结果　 2 5例颅内生殖细胞瘤中的 10例发生转移 ,转移发生率 40 %,其增强MRI可表现为 :①软脑膜条索状增粗 ;②脑或脊髓表面的结节状信号 ,病变累及部位弥漫性肿胀 ,信号不均 ,脑沟消失 ;③肿瘤前部楔形缺损或三脑室后部“笔尖样”扩大 ;④室管膜下层片状或弥漫性高信号 ;⑤颅外转移征象等。结论　增强MRI能准确检测颅内生殖细胞瘤转移 ,为临床确立合理治疗方案提供有价值信息。     

Leptomeningeal metastasis: MR imaging

Seven patients with central nervous system neoplasia and leptomeningeal metastases, proved either at initial diagnosis or on follow-up with contrast material-enhanced computed tomography (CT), were evaluated with magnetic resonance (MR) imaging. In two patients, diffuse sulcal enhancement on CT scans was inapparent on T1- or T2-weighted MR images. Likewise, in four patients diffuse cisternal enhancement on CT scans was not identifiable with MR. Nodular or focal cisternal masses were identified with both CT and MR imaging in three patients; in two, however, MR imaging provided less information. Ependymal and subependymal metastases identified with CT (two patients) were indistinguishable on MR images from periventricular abnormalities of radiation therapy and/or hydrocephalus. These findings suggest that leptomeningeal metastasis may be so subtle or inapparent as to be overlooked with MR imaging alone. Thus, CT and MR imaging should be considered complementary techniques for initial diagnosis and follow-up of tumors with a propensity for leptomeningeal metastasis.