磁共振影像中海马头部浅沟消失对海马区结构硬化的评估

背景：MRI是目前发现检查癫痫患海马硬化的最重要方法，主要表现为海马部位的信号异常，除此以外，MRI其他的征象对海马硬化也有提示作用。目的：通过对颞叶癫痫患的MRI信号分析，探讨海马头部浅沟消失对癫痫患海马硬化评估的价值。设计：非随机，盲法(数据收集、结果评价)，空白对照临床实验。单位：两所大学医院的放射科。对象：1996-09／2002-12在上海第二医科大学附属新华医院放射科确诊为颢叶癫痫患18例。同期选择以头痛症状来本院进行MRI检查，排除脑部存在异常的18例年龄相匹配的检查作对照组。方法：有16例癫痫患和18例对照组MRI检查机型为GE1．5T Horizon LX全身MR机，另2例癫痫患采用GEl．5T Signa全身MR机。由2位熟悉海马解剖，但不知具体临床和手术情况的放射科医生分析记录两组36例的72个海马头部浅沟有无消失，并将其分为3个级别：消失、几乎消失和存在，同时分析记录海马有无萎缩性改变和信号异常。主要观察指标：头部浅沟的显示情况，海马头部大小和信号改变情况。结果：18例海马硬化患中，16例硬化侧海马头部浅沟消失，1例硬化侧海马头部浅沟明显变浅，几乎消失，1例硬化侧海马头部浅沟存在。硬化侧海马头部均有萎缩，并在T2WI和液体衰减恢复(FLAlR)成像呈高信号。海马头部浅沟消失对海马硬化诊断的敏感性为89％，(16／18)，特异性为100％。结论：海马头部浅沟消失是诊断海马硬化的一个可靠征象，结合患侧海马有萎缩性改变和T2加权成像信号增高，可肯定诊断海马硬化。     

MRI对海马硬化所致颞叶癫痫的诊断价值

对19例癫痫患者行垂直于海马长轴的斜冠状液体衰减反转恢复序列（FLAIR）和T1WI、T2WI成像。结果19例手术病理证实均为海马硬化。其中左侧海马硬化11例，右侧海马硬化8例。19例患侧海马均有萎缩性改变，并且在T2WI和FLAIR成像呈高信号，17例患侧海马头部浅沟明显消失。认为海马体积缩小、信号增高及海马头部浅沟消失是海马硬化的特征性MRI表现，可为临床医生提供精确的定位和定性诊断。     

MRI对儿童癫痫患者海马硬化的应用价值分析

目的探讨磁共振成像(MRI)对儿童癫痫患者海马硬化的应用价值分析。方法选取2013年11月至2014年11月经手术治疗确诊的癫痫海马硬化患者23例。通过对23例儿童癫痫海马硬化患者进行磁共振成像常规MRI扫描、液体衰减反转恢复序列(FLAIR)薄层扫描、辅助T2W-FLAIR序列、横断位GM-only、三维T1加权成像(3DT1W)与海马单体素磁共振波谱成像(1H-MRS),分析MRI检查对癫痫患者海马硬化的应用价值。结果 MRI检查显示海马结构特征清晰,23例患者在FSET1WI序列图像中海马面积均有萎缩性改变;20例患者出现单侧海马体积缩小(左侧11例,右侧9例);3例患者出现海马体积双侧缩小;FLAIR序列中23例患者海马病变处信号均增高,FSET2WI序列19例患者病变侧海马信号增高,4例无明显变化;海马病变侧头部浅沟明显消失20个,病变侧白质萎缩3个,病变侧颞角增大1个,病变侧颞叶萎缩2个;海马硬化在MRI图像中以表面硬化、颞角增大、T2WI序列中海马信号异常升高、海马体积缩小、病变侧NAA峰下降等为主要特征。结论 MRI各序列的扫描图像对海马硬化区域显示直观,可定量分析脑组织内生化代谢的异常变化,可为深入地了解癫痫灶的病理生理改变及临床手术定位提供丰富的影像学资料。     

儿童颞叶中内侧硬化所致颞叶癫痫的MRI研究

目的 对儿童颢叶癫痫进行前瞻性MRI研究分析。探讨儿童颢叶癫痫的MRI表现特征。方法 对127例临床和脑电图检查诊断为颢叶癫痫的儿童进行MRI多序列成像．分析研究颞叶的形态结构、信号并判断海马有无萎缩性改变。结果 127例颢叶癫痫患儿中，9例(7．1％)海马有萎缩性改变，且在T2加权成像和液体率减恢复(F1AIR)成像上呈高信号。9例中，6例伴有海马受累同侧颞叶信号异常；3例伴有同侧颞叶皮层结构不良；1例伴有同侧颞叶萎缩。结论 颞叶中内侧硬化是儿童颢叶癫痫的一个相对少见原因，受累侧海马MRI表现为萎缩和信号异常，同时常伴海马外颞叶结构受累。     

3.0TMR质子波谱成像诊断难治性颞叶癫痫海马硬化的价值

目的探讨3.0T MR质子波谱成像（proton magnetic resonance spectroscopy,1 H-MRS）在难治性颞叶癫痫海马硬化早期诊断中的应用价值。方法 64例难治性颞叶癫痫海马硬化患者（观察组）,行1 H-MRS检查,分析海马N-乙酰基天门冬氨酸（N-acetylaspartate,NAA）、胆碱复合物（choline,Cho）与肌酸复合物（creatine-phosphocreatine,Cr）波峰特点及NAA/（Cho＋Cr）比值,与21例体检健康者（对照组）进行比较。结果观察组1 H-MRS检查发现左侧海马异常10例,右侧异常7例,双侧异常47例;与对照组比较,观察组海马异常侧1 H-MRS图像主要表现为NAA波峰降低,Cr和Cho波峰增高;观察组海马单侧异常者患侧NAA/（Cho＋Cr）值（0.484±0.145）低于健侧（0.846±0.120）（P〈0.05）,双侧异常者主要异常侧NAA/（Cho＋Cr）值（0.382±0.115）低于对侧（0.563±0.167）（P〈0.05）;对照组双侧NAA/（Cho＋Cr）均值为0.843±0.122,高于观察组海马单侧异常者患侧、双侧异常者双侧（P〈0.05）。结论 1 H-MRS可反映神经元的丢失和/或胶质细胞增生,在难治性颞叶癫痫海马硬化早期诊断中有重要价值。     

40例颞叶癫痫与海马硬化的MRI研究

目的探讨原发性颞叶癫痫与海马硬化-MRI之间的关系。方法40例颞叶癫痫患者的海马面积计算采用电子计算机,用BIOCOM2000软件分析MRI图像,并计算出海马体积,用AI(不对称指数)表示海马萎缩程度。结果有海马萎缩者占70%,无海马萎缩者占30%,与脑电图检查非常符合,其敏感性达93%,特异性为86%。结论原发性颞叶癫痫与海马硬化有关。MRI是检测海马硬化的首选方法。     

3.0T磁共振波谱对颞叶癫痫的定侧诊断价值

目的：通过对颞叶癫痫的磁共振波谱研究,探讨3.0T超高场强MRS在颞叶癫痫的定侧诊断价值。方法对40例临床诊断颞叶癫痫患者及20例正常志愿者进行研究,所有实验对象行双侧海马的常规MRI和1H-MRS扫描,MR成像序列为轴位SE T1WI、T2WI,对双侧海马体部进行多体素波谱成像,将正常对照组MRS结果作为标准,评价颞叶癫痫患者MRS代谢物比值特点,分析MRS对颞叶癫痫定侧诊断价值。结果常规MRI诊断海马硬化共21例。癫痫组患侧、健侧与对照组间NAA/（Cho＋ Cr）、NAA/ Cho比值差异均有统计学意义（F分别=12.89、15.73,P均＜0.05）。癫痫组患侧与健侧、患侧与对照组NAA/（Cho＋Cr）、NAA/Cho差异均有统计学意义（q分别=7.32、8.47、7.33、8.47,P均＜0.05）;而癫痫组健侧与对照组差异无统计学意义（q分别=1.13、1.13,P均＞0.05）。结论常规MRI检查对颞叶癫痫的定侧具有一定的价值;3.0T超高场强MRS与常规MRI联合应用可以提高颞叶癫痫定侧的准确性。     

常规MRI图像纹理分析对颞叶癫痫海马硬化的诊断价值

目的探讨常规MRI图像纹理分析对颞叶癫痫海马硬化的诊断价值。材料与方法应用Mazda软件分析22例病理证实为颞叶癫痫海马硬化患者的术前斜冠状位海马T2 FLAIR图像纹理。采用3种特征选择方法[Fisher系数(fisher coefficient,Fisher)、分类错误概率联合平均相关系数(classification error probability combined with average correlation coefficients,POE+ACC)、交互信息(mutual information,MI),3种方法联合简称为FPM]提取患者双侧海马的纹理特征;4种统计方法[线性判别分析(linear discriminant analysis,LDA)、非线性判别分析(nonlinear discriminant analysis,NDA)、原始数据分析(raw data analysis,RDA)、主要成分分析(principal component analysis,PCA)]判别患者海马硬化侧与正常侧,结果以错判率表示。同时由2名影像医师对22例患者的MR图像进行诊断。比较两种判断结果的差异。结果采用FPM选择方法及NDA统计学方法误判率最小(2/44,4.55%),较影像医师的错判率(11/44,25%)低,差异有统计学意义(P0.05)。结论常规MRI纹理分析可为颞叶癫痫海马硬化的诊断提供可靠的客观依据。     

磁共振波谱分析对颞叶内侧癫痫患者脑功能定位的监测和评估作用

目的：通过对颞叶癫痫患者的磁共振波谱分析(magnetic resonance spec-troscopy，MRS)结果进行分析，探讨其在诊断颞叶内侧癫痫中的作用与意义。方法：经手术治疗的颞叶癫痫患者19例，外侧型5例，内侧型14例，经术中皮质脑电图及手术后病理结果证实；手术前行脑电图、MRI及MRS检查。结果：5例颞叶外侧型癫痫患者海马区MRS检查均无异常，14例颞叶内侧型癫痫患者中6例海马区MRI显示异常，14例MRS检查均显示异常，其中1例显示双侧异常，经硬膜下埋藏电极检查左侧明显。结论：MRS可在MRI出现改变之前发现海马硬化，MRS诊断灵敏且特异性高，是颞叶内侧癫痫诊断治疗、病变功能区域监测及评估的一个可靠方法。     

联合磁源性影像和磁共振波谱技术评估颞叶癫痫的价值

目的：探讨磁源性成像（MSI）和磁共振波谱（^1H—MRS）技术结合在颞叶癫痫诊断定位中的价值。方法：设健康对照者10例，特发颞叶癫痫患者8例，应用MEG定位痫性病灶，选取MEG异常区域、对侧相应区域和双颞叶内侧区域测量NAA／Cho值，并观察是否存在海马硬化。结果：8例患者MEG检查结果均异常，6例MEG异常相应区域MRS检查NAA／Cho值减少，符合率为62．5％；MRI显示海马硬化2例，MRI正常6例，颞叶内侧MRS扫描未见明显改变。结论：联合MSI和MRS技术可进一步提高颞叶癫痫致痫灶的定位准确性。     

T2 relaxometry can lateralize mesial temporal lobe epilepsy in patients with normal MRI

In unselected patients with intractable temporal lobe epilepsy (TLE), approximately 15% do not have detectable hippocampal atrophy on MRI. The purpose of this study was to evaluate whether T2 relaxometry can identify hippocampal pathology and lateralize the epileptic focus in patients with intractable TLE, who do not demonstrate hippocampal atrophy on volumetric MRI (MRIV). We selected 14 patients with unilateral TLE who had unilateral atrophy and 11 patients with unilateral TLE who had no evidence of atrophy on MRIV. Images were acquired on a 1.5 T MR scan using a dual echo sequence with 23 contiguous oblique coronal slices in all patients and in 14 healthy subjects. Fitting a single exponential decay equation to the imaging data generated T2 maps. Averages of six slices containing the head, body, and tail of the hippocampus were used to calculate hippocampal T2 relaxation times (HT2). The epileptic focus was defined by history, video-EEG, and surgical response. All TLE patients with hippocampal atrophy and 9/11 (82%) patients with normal MRI had abnormally high HT2 ipsilateral to the epileptic focus. Bilateral abnormal HT2 were found in 6/14 (43%) of patients with unilateral hippocampal atrophy and 2/11 (18%) of patients with normal MRI. However, this increase was always greater ipsilateral to the epileptic focus. Qualitative hippocampal pathology showed gliosis and neuronal loss in 10/14 operated patients with hippocampal atrophy on MRIV and in 5/7 operated patients with normal MRI. In conclusion, hippocampal T2 mapping provides evidence of hippocampal damage in the majority of patients with intractable TLE who have no evidence of atrophy on MRI and can correctly lateralize the epileptic focus in most patients.     

特发性颞叶癫痫的MRI海马T2弛豫时间测量

[摘要] 目的：探讨海马T2弛豫时间（HCT2）在特发性颞叶癫痫（TLE）评价中的价值，并为后续的TLE病例HCT2测量与手术预后相关研究提供基础数据。方法：对36例全面性癫痫（GEP）、23例非颞叶部分性癫痫（NTPE）、26例TLE以及60例正常对照者（CL）进行HCT2测量，并分析其差异。结果：TLE组高侧平均HCT2较CL组增高7.5518ms，较GEP组及NTPE组增高4.1639ms和3.7293ms。TLE组低侧及GEP组和NTPE组低侧、高侧较CL组相应侧别分别增高2.7547ms、3.1347ms、3.2829ms、3.4669ms和3.9016ms。TLE组平均HCT2低/高比率较CL组、GEP组、NTPE组分别降低0.0482、0.0456和0.0425。结论：TLE组病灶侧HCT2明显高于CL组、GEP组及NTPE组，HCT2低/高比率降低是TLE的较特异表现。     

PET/CT和MRI术前定位神经节细胞胶质瘤相关药物难治性癫痫

目的 评价¹⁸F-FDG PET/CT脑显像和头颅MRI术前定位神经节细胞胶质瘤（GG）相关药物难治性癫痫的价值。方法 回顾性分析23例药物难治性癫痫、且术后病理证实为GG患者，术前均接受MR及PET/CT检查；定性分析MRI信号特点及PET/CT低代谢范围，与术后CT所示手术区域相对照，分析两种方法术前定位GG相关药物难治性癫痫的价值。结果 23例中，12例致痫灶为单一病理类型，11例为多重病理类型，包括5例GG和皮质发育不良（FCD）、4例GG和皮质胶质增生、1例GG累及海马及1例GG、FCD和海马硬化。23例中，18例MRI显示单一部位实性或囊实性异常信号，其中8例（单一病理类型）与手术切除致痫灶范围完全一致；5例MRI阴性。¹⁸F-FDG PET/CT示8例幕上单一部位葡萄糖代谢减低，均与手术所示GG病灶部位一致；15例幕上多部位代谢减低，其中11例与手术切除范围完全一致。MRI定位准确率34.78%，阳性率78.26%；¹⁸F-FDG PET/CT定位准确率82.61%，阳性率为100%（P均<0.05）。结论 ¹⁸F-FDG PET/CT脑显像术前定位GG相关药物难治性癫痫优于MRI；联合应用二者有助于提高定位精准度。     

Voxel-based diffusion tensor imaging in patients with mesial temporal lobe epilepsy and hippocampal sclerosis

BACKGROUND: Mesial temporal lobe epilepsy (mTLE) with hippocampus sclerosis (HS) is an important cause for focal epilepsy. In this study, we explored the integrity of connecting networks using diffusion tensor imaging (DTI) and two whole-brain voxel-based methods: statistical parametric mapping (SPM) and tract-based spatial statistics (TBSS). METHODS: Thirty-three consecutive patients with mTLE and HS undergoing presurgical evaluation were scanned at 3 T, a DTI data set was acquired and parametric maps of fractional anisotropy (FA) and mean diffusivity (MD) were calculated. Twenty-one patients had left hippocampal sclerosis (LHS) and 12 patients had right HS (RHS). These groups were compared to 37 normal control subjects using both SPM5 and TBSS. RESULTS: The ipsilateral temporal lobe showed widespread FA reduction in both groups. The limbic system was clearly abnormal in the LHS group, also involving the arcuate fasciculus. In RHS, changes were more restricted but also showed involvement of the contralateral temporal and inferior frontal lobe. Increased MD was found in the ipsilateral hippocampus by SPM that was only marginally detected by TBSS. In white matter regions, however, TBSS was more sensitive to changes than SPM. CONCLUSION: DTI detects extensive changes in mTLE with HS. The affected networks were principally in the ipsilateral temporal lobe and the limbic system but also the arcuate fasciculus. SPM and TBSS gave complementary information with higher sensitivity to FA changes using TBSS.     

热性惊厥与伴海马硬化的癫痫

目的回顾性分析伴海马硬化癫痫患者的临床资料,探讨热性惊厥与海马硬化的关系。方法 507例癫痫患者由MRI证实伴海马硬化。根据儿童期是否出现热性惊厥,将患者分为两组:即热性惊厥组(FS+组)和无热性惊厥组(FS-组),进一步将FS+组分为1岁以内亚组和1⁵岁亚组。采用卡方检验和t检验对两组和两亚组在性别、非热性发作起始年龄、热性惊厥年龄与非热性发作间的间隔时间、海马硬化出现的单双侧以及是否实施癫痫手术等参数进行统计学比较。结果 507例患者中,热性惊厥史阳性者88例,占17.4%。癫痫非热性发作平均起病年龄FS+组明显低于FS-组[(10.5±6.4)岁vs.(15.7±10.8)岁,P=0.000]。实施手术治疗的比例FS+组稍多于FS-组[37例(42.0%)vs.135例(32.2%),P=0.051]。FS+组和FS-组及FS+亚组在性别、海马硬化的单双侧等参数比较无统计学差异。FS+亚组在非热性发作平均起病年龄、FS年龄与非热性发作间的间隔时间、是否实施手术等方面无统计学差异。FS+组接受手术治疗的患者病程明显长于药物治疗者[(8.1±4.4)年vs.(7.1±6.9)年,P=0.009]。手术治疗随访者中92.3%达EngelⅠ级。结论伴海马硬化的癫痫患者中儿童期出现热性惊厥史者,出现癫痫非热性发作的平均起病年龄明显早于无热性惊厥史的海马硬化癫痫患者;这部分患者可能进行癫痫手术治疗的预后更好。     

A hippocampal lesion detected by high-field 3 tesla magnetic resonance imaging in a patient with temporal lobe epilepsy

Nearly 80% of patients with temporal lobe epilepsy have some types of lesion identified by conventional 1.5 tesla (T) magnetic resonance imaging (MRI). We performed high-field 3 T MRI in a 5-year-old patient with recurrent complex partial seizures who was diagnosed as having right temporal lobe epilepsy based on the results of single photon emission computed tomography and ictal video-electroencephalogram monitoring, because 1.5 T MRI failed to detect any abnormalities in the suspected region. High-field 3 T MRI revealed a small high-intensity lesion on fast spin-echo short inversion time inversion-recovery images of the hippocampus, possibly responsible for the seizures. This is the first report detecting a hippocampal lesion by 3 T MRI, which could not be found by conventional 1.5 T MRI.     

Phase-locking characteristics of limbic P3 responses in hippocampal sclerosis

Amplitudes of the P3 recorded invasively from the medial temporal lobe (MTL-P3) have been reported to be reduced on the side of a mediotemporal epileptogenic focus. This reduction has been attributed to the massive cell loss within the hippocampus associated with hippocampal sclerosis. It has remained unclear how functional connectivity between the hippocampus and rhinal cortex, as well as within the hippocampus, is altered in hippocampal sclerosis. To investigate this issue, we analyzed to what extent stimulus-related phase-locking and power changes within the low-frequency range (2-30 Hz) and within the gamma band (32-48 Hz), as well as rhinal-hippocampal phase synchronization contribute to the averaged MTL-P3 potentials. Event-related responses were recorded via bilateral depth electrodes in epilepsy patients with unilateral hippocampal sclerosis, who performed a visual oddball experiment. On the contralateral (nonsclerotic) side, successful target detection was associated with an increase of power and phase locking of hippocampal activity in both the low-frequency range and in the gamma range. Besides, there were rhinal-hippocampal synchronization enhancements in the theta and gamma range. On the ipsilateral (sclerotic) side, the event-related power increase in the low-frequency range had almost disappeared, a finding likely to be explained by the loss of principle neurons. However, low-frequency phase-locking, rhinal-hippocampal synchronization, as well as event-related power changes in the gamma range persisted ipsilaterally, although there were differences in temporal and spectral characteristics. These findings support the hypothesis that functional connectivity between hippocampus and rhinal cortex, as well as intrahippocampal connectivity, are partially preserved in hippocampal sclerosis.     

Hippocampal sclerosis: histopathology substrate and magnetic resonance imaging.

The term hippocampal sclerosis was originally used to describe a shrunken and hardened hippocampus, which histologically displayed neuronal loss and glial proliferation. These alterations are mainly located in the hilus of the dentate gyrus and in the CA1 and CA3 pyramidal cell layers but all hippocampal regions may show neuronal cell loss to varying degrees. A number of morphologic and cytochemical findings are associated with mesial temporal sclerosis, especially within the dentate gyrus. These changes include selective loss of inhibitory interneurons, abnormal sprouting of axons, reorganization of neural transmitter receptors, alterations in second messenger systems, and hyperexcitability of the granule cells. Extrahippocampal pathology is also found at other temporal lobe structures. Frequent extrahippocampal pathology affects the amygdala, first seen with neuronal cell loss and gliosis in the laterobasal complex. Surgical removal of this epileptogenic area can be curative or provide significant reduction in seizure frequency in the majority of individuals. Magnetic resonance imaging (MRI) is highly sensitive in detecting and locating mesial temporal sclerosis when a correct MRI temporal lobe protocol is used. The most important MRI findings, atrophy and abnormal T2 signal, allow us to detect mesial temporal sclerosis in the majority of the cases. Secondary MRI findings help in the diagnosis and lateralization of mesial temporal sclerosis in patients with subtle primary findings and in cases of bilateral hippocampal abnormalities. The development of advanced magnetic resonance (MR) techniques, such as functional MR, diffusion, or transference of magnetization, will lead to greater understanding of this pathology and will improve our diagnostic capacity.