局灶性脑皮层发育不良的MRI诊断

目的 研究局灶性脑皮层发育不良(focal cortical dysplasia,FCD)的MRI表现特点.资料与方法 回顾性分析23例经手术病理证实的FCD患者的MRI表现.常规行横断位、矢状位及垂直于海马长轴的斜冠状位扫描,获得T1 WI、T2WI及液体衰减反转恢复序列(FLAIR)图像.结果 23例FCD病灶均表现为一侧大脑半球内局限性病变.病灶区域皮质增厚18例,灰白质分界模糊20例,皮层下白质异常信号22例,脑回、脑沟形态异常14例,邻近蛛网膜下腔局限性扩大4例.T1WI、T2WI及FLAIR显示灰白质分界模糊分别为6例、20例及18例;皮层下白质异常信号分别为3例、16例及19例;脑回、脑沟形态异常分别为12例、10例及11例.结论 FCD的MRI表现为皮质增厚、灰白质分界模糊、皮层下白质异常信号、脑回、脑沟形态异常及邻近蛛网膜下腔局限性扩大.T2WI及FLAIR显示灰白质界限、白质内异常信号较T1WI敏感,T1WI显示脑回、脑沟形态有一定的价值.     

局灶性脑皮质发育不良的MRI表现

目的 探讨局灶性脑皮质发育不良(FCD)的MRI特点.方法 回顾性分析经手术病理确诊为FCD的110例患者的MR表现.按照Palmini分类,将其分为Ⅰ型及Ⅱ型.统计FCD的脑内分布及影像诊断阳性率.结果 FCD Ⅰ型81例,FCDⅡ型29例;单一合并海马硬化49例,单一合并占位性病变3例,有三重病理表现7例.病灶位于颞叶共86例.影像诊断FCD阳性17例,其中FCD Ⅰ型诊断率14.8％(12/81),FCDⅡ型17.2％(5/29);海马硬化诊断特异度90.7％,灵敏度42.9％.常规MR扫描,FCD Ⅰ型异常表现不明显,FLAIR序列可见稍高信号;FCDⅡ型可有典型的皮层增厚、灰白质分界模糊、压水高信号及局限性脑萎缩;多重病理者海马硬化或占位性病变周围见皮层的影像学异常.结论 FCD好发于颞叶,以Ⅰ型为多,可合并多重病理表现,虽然FLAIR序列对FCD较为敏感,但目前影像诊断率仍较低.海马硬化或占位性病变要注意病变相邻皮质的微小异常或占位周围的灰白质改变.     

局灶性脑皮质发育不良病理分型的MRI特点

目的探讨不同病理分型的局灶性脑皮质发育不良（FCD）的MRI特点。方法回顾分析行癫痫手术治疗后病理符合FCD患者的临床资料，所有患者术前均行MR检查。根据Palmini的FCD分型标准，分型后分别总结患者的MRI特点。结果共28例患者符合标准，其中FCDⅠ型与Ⅱ型各14例。FCDⅠ型患者中，9例病灶位于颞叶，6例合并海马硬化。其中MRI表现异常者8例，表现为灰白质交界不清，局部皮层增厚、形态异常等特征；FCDⅡ型患者中，病灶位于额叶7例，2例合并海马硬化。其中MRI表现异常者11例，多表现为脑回形态异常，液体抑制反转恢复序列（FLAIR）、T2WI上白质信号增高，以及白质内条带状异常增高信号向脑室方向延伸等特点。结论不同病理分型的FCD在MRI上表现的特点有所不同，了解这些特点有助于提高癫痫外科术前评估的准确性以及对手术预后的判断。     

局灶性脑皮层发育不良 MRI 表现与病理相关性分析

目的：研究局灶性脑皮层发育不良（FCD ）M RI表现与病理相关性。方法经手术病理证实FCD患者74例,根据 FCD的M RI表现,把FCD分为3种类型：放射带型、高信号型、轻微型。分析FCD的M RI分型与病理类型的相关性。结果74例患者中,放射带型12例,表现皮层和／或皮层下T2 WI／FLAIR上高信号,白质内三角形或带状异常信号从皮层向侧脑室方向延伸。高信号型32例,表现皮层和／或皮层下片状 T2 WI／FLAIR高信号,伴有皮层增厚,但是无放射带表现。轻微型30例,仅表现皮层T2 WI／FLAIR略高信号,伴有皮层增厚,但无皮层下高信号表现。放射带型FCD的病理类型多为ⅡB型,高信号型 FCD的病理多表现为ⅡA型及ⅡB型,轻微型FCD病理稍多见于ⅠA型和ⅠB型。结论了解FCD的M RI表现及分型有利于提高FCD的正确诊断,并有助于提示病理类型。     

不同病理类型局灶性皮质发育不良的MRI特征

目的 总结局灶性皮质发育不良(FCD)的MRI特征性表现,探讨不同病理类型FCD各自的特异性MRI征象.方法 回顾性分析经病理证实的44例FCD患者的MRI表现.将44例患者根据病理检查结果分为FCD Ⅰ型和Ⅱ型,观察以下MRI征象在两种类型中的出现情况:(1)局灶性皮层增厚;(2)灰、白质分界不清;(3)液体衰减反转恢复(FLAIR)序列和(或)T2WI上白质内向脑室方向延伸的锥形异常增高信号;(4)脑叶发育不全;(5)FLAIR上灰质信号强度增高;(6)T2WI上灰质信号强度增高;(7)FLAIR上皮层下白质信号强度增高;(8)T2WI上皮层下白质信号强度增高;(9)T1WI上皮层下白质信号强度减低.2组间的比较采用χ2检验及校正χ2检验.结果 44例FCD患者中FCD Ⅰ型30例,FCDⅡ型14例.共32例患者MRI表现异常,灰、白质分界不清为最常见征象(23例).其中FCD Ⅰ型患者中MRI表现异常者21例,特征性表现为脑叶发育不全11例,FCDⅡ型脑叶发育不全0例,两种类型间差异有统计学意义(连续性校正χ2=5.0286,P=0.0249).FCDⅡ型患者中MRI表现异常者11例,特征性表现为局灶性皮层增厚10例,FCD Ⅰ型为11例(χ2=4.6234,P=0.0315);FLAIR上白质信号增高9例,FCD Ⅰ型为7例(χ2=6.9180,P=0.0085);白质内向脑室方向延伸的锥形异常增高信号4例,FCD Ⅰ型为0例(连续性校正χ2=6.2883,P=0.0122);差异均有统计学意义.其他征象两种类型间差异无统计学意义.结论 不同病理类型FCD的MRI表现各有特点,了解这些特点有助于不同病理类型FCD的早期诊断和术前评估.     

局灶性脑皮质发育不良的扩散张量成像初步研究

目的 探讨DTI技术诊断局灶性脑皮质发育不良(FCD)的价值.方法 回顾性分析12例FCD患者的临床、MRI及DTI等资料.DTI经过图像后处理,获得平均扩散系数(MD)和部分各向异性分数(FA)图及彩色编码张量图,于FCD的皮质下白质区及对侧相应皮质下白质区设置椭圆形ROI,测量每个ROI的MD及FA值.病灶侧与对侧MD、FA值的比较采用配对t检验.扩散张量纤维束示踪成像(DTT)以T_2 WI图像为参照,ROI设置同DTI,以ROI中的任一点作为种子点,获得通过该ROI区域的所有白质纤维束示踪图像.结果 12例患者MR平扫均显示局灶性脑皮质增厚及灰白质界限不清,其中7例显示皮质下白质稍长T_1、稍长T_2信号,2例皮质下白质萎缩,3例皮质下白质无明显异常.DTI分析显示FCD邻近皮质下白质与对侧比较FA值明显下降(患侧0.31±0.05,对侧0.42±0.08,t=-3.995,P<0.01),MD值明显上升[患侧(1.02±0.16)×10~(-3)mm~2/s,对侧(0.86±0.13)×10~(-3) mm~2/s,t=2.655,P<0.05],差异均有统计学意义.DTT显示10例FCD患者皮质下白质纤维束较对侧明确减少,2例较对侧可能减少,主要表现为皮质下白质纤维稀疏,与深部白质纤维间联系减少.结论 FCD除了导致脑皮质结构异常外,也影响局部皮质下白质纤维的发育,DTI是常规MR检查的重要补充.     

足月新生儿低血糖脑病的MRI表现

目的 探讨足月新生儿低血糖脑病的MRI表现.方法 回顾性分析16例低血糖脑病的MR资料,其中男10例,女6例,所有病例均在患者出生后6 d内进行,包括常规T1WI,T2WI和Flair,DWI扫描.其中4例1~3月后再次复查MR.结果 16例首次检查T1异常8例,表现为皮层下白质呈低信号,4例皮层呈高信号.T2异常6例,表现为高信号区.DWI异常12例,表现为对称性高信号区.分布部位:双侧顶枕叶10例,胼胝体压部4例,双额叶1例,双屏状核1例,侧脑室旁白质4例,小脑上脚、脑干腹侧1例.1~3月后复查4例,有2例表现为局限性脑皮层萎缩,胼胝体变细.结论 足月新生儿低血糖脑损伤最易发生顶枕叶后部脑组织,其次胼胝体,小脑亦可受累.DWI上对称性高信号具有一定的特征性.     

MR双反转恢复成像在灰质异位诊断中的初步应用

目的 初步探讨MR双反转恢复(DIR)序列在灰质异位诊断中的价值.资料与方法 回顾性分析本院9例灰质异位症患者的影像学资料,重点观察灰质异位病灶在DIR上的表现.结果 根据病灶形态和位置分型:皮层下灰质异位(SCH)5例、室管膜下灰质异位(PNH)2例、皮层下带状灰质异位(SBH)2例;在DIR上,脑内灰质结构表现为高信号,白质结构表现为低信号,灰质异位病灶均表现为边界清楚、形状不规则的高信号,与脑皮层和灰质核团的信号相一致.结论 DIR序列能够选择性抑制脑脊液和白质的信号,突出显示灰质结构,灰白质对比度高,对灰质异位的诊断具有显著价值.     

脑发育性静脉异常的MR诊断

目的:评价MRI对脑发育性静脉异常(DVA)的诊断价值。方法:收集MR诊断为DVA的患者51例,均行MR平扫及增强检查,其中11例行磁敏感加权成像(SWI),回顾性分析其MR表现。结果:51例DVA中发生于额叶白质27例,顶叶白质9例,颞叶4例,基底节区2例,小脑半球9例;合并出血2例,均位于幕下;并发海绵状血管瘤2例。MR平扫显示病灶14例,其中表现为条状流空信号者10例,表现为T2WI放射状高信号者4例;MR增强检查显示所有病灶,表现为"海蛇头"样强化特征。11例行SWI者均能清晰显示病灶,表现为"海蛇头"样低信号影。结论:DVA多发生于幕上额顶叶白质及小脑半球,合并出血少见,可并发海绵状血管瘤。MR平扫难以显示细小病灶,MR增强检查是显示DVA的有效方法,SWI对小静脉病变较敏感,能取代MR增强检查用于发育性静脉异常的诊断和随访。     

儿童结节性硬化症14例的磁共振表现

目的 探讨结节性硬化症(TSC)的磁共振影像表现。方法 收集2002年3月至2005年4月间临床证实的结节性硬化症14例,全部病例均进行MR检查,其中3例进行增强检查。不合作儿童检查前采用6.5%水合氯醛保留灌肠镇静睡眠。结果 全部病例均显示大小不等(1~5mm)的室管膜下结节。皮层或皮层下结节10例,表现为脑回核心样病灶和H型病灶。白质异常信号6例,分别呈线状、楔形、不规则形。室管膜下巨细胞星形细胞瘤2例,肾血管平滑肌脂肪瘤1例。结论 MRI对TSC诊断的敏感性高,是首选的影像学检查方法。室管膜下结节是TSC最重要的MR影像学表现之一,以T1加权成像(T1WI)及梯度回波序列显示效果最佳。T2加权成像(T2WI)及液体衰减反转恢复序列(FLAIR)对TSC大脑皮层或皮层下区结节、脑白质区病灶的显示优于T1WI。     

MRI of focal cortical dysplasia

We studied nine cases of focal cortical dysplasia (FCD) by MRI, with surface-rendered 3D reconstructions. One case was also examined using single-voxel proton MR spectroscopy (MRS). The histological features were reviewed and correlated with the MRI findings. The gyri affected by FCD were enlarged and the signal of the cortex was slightly increased on T1-weighted images. The gray-white junction was indistinct. Signal from the subcortical white matter was decreased on T1- and increased on T2-weighted images in most cases. Contrast enhancement was seen in two cases. Proton MRS showed a spectrum identical to that of normal brain. Received: 10 September 1997 Accepted: 6 January 1998     

Imaging and radiological-pathological correlation in histologically proven cases of focal cortical dysplasia and other glial and neuronoglial malformative lesions in adults

Focal cortical dysplasia (FCD) is a pathological entity first described in 1971. Other more subtle cortical malformations found in patients with epilepsy include microdysgenesis (MD), and glioneuronal hamartias. Although these glial and neuronoglial malformations have distinct histological features, there is terminological confusion in the radiological literature. Few cases have been reported in adults with both imaging and histology. We address these issues, giving a radiological-pathological correlation of histologically proven cortical malformations in adults. We describe clinical, radiological and histological features of 12 cases (five FCD, five MD with glioneuronal hamartias, and two hamartomas), unassociated with other conditions, and discuss them in the light of the literature. FCD is usually seen on MRI as cortical thickening, with or without signal change, which may extend into the adjacent white matter. On histology, abnormal neurons and/or glial cells, blurring of the grey-white matter interface, myelin pallor, demyelination, and gliosis may be found. Glioneuronal hamartias and hamartomas usually appear as complex masses on MRI. FCD and hamartias may be associated, and a combination of imaging findings may be seen on MRI. Atrophy of the ipsilateral hippocampus may be present on MRI in patients with hamartias, and minor cell loss on histology, but not definitive hippocampal sclerosis. Although the imaging findings of cortical malformations are protean, some characteristic MRI features, with histological correlates, may be found. The relevance of most of these observations remains unclear. Received: 14 December 1998/Accepted: 2 July 1999     

Distinctive MRI features of the epileptogenic zone in children with tuberous sclerosis

Objective

Localization of the epileptogenic zone (EZ) is challenging in children with tuberous sclerosis complex (TSC). We sought to ascertain whether brain MRI could identify the EZ in TSC patients independent of the clinical and diagnostic data.

Methods

Presurgical MRI's of 34 children with TSC who underwent epilepsy surgery at Miami Children's Hospital were retrospectively reevaluated by experts blinded to all other data. Changes typical of TSC (tubers, calcifications, cystic changes) and abnormalities of the perituberal cortex typical of focal cortical dysplasia (FCD) (increased cortical thickness, abnormal gyration, transmantle change, gray/white matter junction blurring) were identified and their localization was compared with the resection site. Sensitivity, specificity and accuracy of individual MRI features to localize the EZ were determined and statistically compared between postoperatively seizure-free and non-seizure-free patients as well as clusters of features typical of FCD and TSC.

Results

MRI alone correctly localized the resection cavity in all 19 postoperatively seizure-free patients and 12 of 15 non-seizure-free subjects. Sensitivity, specificity and accuracy of MRI features typical of FCD to localize EZ (90%, 96% and 96%, respectively) were superior to those typical of TCS (79%, 75% and 75%, p < 0.0001). Increased cortical thickness and abnormal gyral formation outside tubers occurred only in the resection site. Resection sites were better predicted by MRI in seizure-free than in non-seizure-free patients.

Conclusion

Thorough MRI evaluation identifies the EZ in a significant proportion of TSC patients. Epileptogenic regions were mostly characterized by “FCD-like” changes outside cortical tubers. The findings may have important practical consequences for surgical planning in TSC.     

MRI在新生儿缺氧缺血性脑病中的随访价值

目的评价MRI对缺氧缺血性脑病(HIE)患儿新生儿期及神经后遗症期随访的价值。方法回顾性分析81例HIE新生儿期及神经后遗症期的常规MRI表现及影像结果。对81例HIE患儿进行2次以上头部MR复查,首次在新生儿期,第2次在4月~4岁。足月儿66例,早产儿15例。结果81例中,2次复查后MRI异常79例(97.5%)。其中:髓鞘化异常59例(72.8%),外部性脑积水53例(65.4%),脑软化26例(32.1%),脑萎缩25例(30.9%),脑白质减少24例(29.6%)及胼胝体发育不良9例(11.1%)。轻度者复查常为外部性脑积水(26/35例)及局限性髓鞘化异常(16/35例),而中度患儿则伴有脑软化灶(12/29例),重度患儿常见脑萎缩(16/17例)或脑白质减少(15/17例)。结论常规MRI可准确反映HIE及神经后遗症期脑的形态学改变,为HIE早期干预和评估预后提供了客观依据。     

Focal cortical dysplasia: comparison of MRI and FDG-PET

PURPOSE: The purpose of this work was to compare the use of MRI and [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) in the diagnosis of focal cortical dysplasia (FCD). METHOD: Nineteen patients with surgically proven FCD were analyzed retrospectively. MRI was performed in all patients, and FDG-PET was performed in 17 patients. We compared the MR and FDG-PET findings of FCD according to the histologic findings that were classified into three grades. RESULTS: Four cases were classified as Grade I, 4 cases as Grade II, and 11 cases as Grade III FCD. The lesions were detected on MRI in 9 (82%) of the 11 patients with Grade III FCD and in only 1 (13%) of the 8 patients with Grade I and II FCD. Cortical hypometabolism of the lesion was revealed on FDG-PET in 6 (86%) of the 7 patients with Grade I and II FCD and in 9 (90%) of the 10 patients with Grade III FCD. The extent of the cortical abnormality was larger on FDG-PET than on MRI in 11 (65%) of the 17 patients. CONCLUSION: FDG-PET is more useful in delineating the cortical abnormality in patients with mild degrees of FCD. The extent of the lesion was larger or similar on FDG-PET compared with that of the MRI.     

线粒体脑肌病的MRI诊断价值

目的 探讨线粒体脑肌病的脑部MRI表现及其诊断价值。资料与方法 对13例线粒体脑肌病患者的临床、实验室及MRI表现进行回顾性分析。结果 13例头部MRI检查均显示异常,对病变的检出率为100％,主要MRI表现为3类：（1）大脑半球多发单侧或双侧病变（7例）,4例呈对称性,病变呈片状等长T1、长T2信号,以一侧或两侧颞顶枕时皮层和皮层下白质最常受累。（2）大脑半球皮层和深部灰质核团同时出现片状等长T1、长T2信号2例。上述两类脑内病变有5例合并脑萎缩。（3）脑实质信号正常,但有脑萎缩4例,其中桥脑、延髓及小脑萎缩3例,大脑半球、脑干、小脑萎缩1例。结论 MRI对线粒体脑肌病的脑内病变显示敏感且准确,对其早期诊断、指导治疗、判断疗效和提示预后具有重要价值。     

结节性硬化的影像学诊断

目的总结结节性硬化的影像学表现特征。方法回顾分析20例经临床、影像及病理证实的结节性硬化患者的脑部CT和MRI表现。结果20例中CT表现为沿侧脑室壁分布的多发室管膜下钙化结节16例,其中多发结节14例,单发结节2例,室管膜下等密度未钙化结节2例,结节大小介于2~12mm。未见明确异常2例。MRI显示多发室管膜下结节19例,单发结节1例,T1WI结节呈等信号或低信号,T2WI呈低信号、等信号或稍高信号。MRI显示脑皮质及皮质下病变19例,呈局限脑回样异常信号;脑白质异常信号7例,分别呈线状、楔形及不规则形。9例MRI增强扫描室管膜下结节多呈轻中度强化,脑实质内结节多不强化。结论结节性硬化的CT和MRI表现均具有特征性。