发作间期PET和MR海马像在难治性颞叶癫癎术前定侧中的应用

目的探讨发作间期18FDG-PET和MR海马像在难治性颞叶癫癎(TLE)致癎源术前定侧中的价值.方法对17例药物难治性TLE患者术前定侧资料及术后随诊情况进行分析.结果本组患者中,有12例(71%)患者MR显示海马硬化(HS),海马萎缩与信号改变常共存,T2加权像和FLAIR序列有利于显示信号的改变.HS侧多提示为致癎源侧.PET检查均显示有至少一侧颞叶低代谢改变,并常多发或范围弥散.PET与MR的定侧准确率分别是100%(13/13)、77%(10/13),经x2检验两者间无差异(P＞0.05).结论18FDG-PET和MR海马像在致癎源定侧中的作用是互补的,当颞叶低代谢侧与海马硬化侧相一致时手术效果较好.     

发作期录像脑电监测在15例难治性颞叶癫痫患者术前定位中的价值

目的 探讨发作期录像脑电监测（IVEEG）在难治性非病变性颞叶癫痫（TLE）致痫源术前定位中的价值。方法 对15例药物难治性TLE患者术前定位资料及术后随诊情况进行分析。结果 所有患者在行长时间IVEEG监测中均捕获到临床发作。在15例患者中，有13例IVEEG显示出一侧起源的局灶爆发性节律性电活动，该放电侧均与最终切除侧相一致，且有11例患者术后效果较好。结论 IVEEG监测不仅有助于明确诊断及发作类型，更为重要的是对于大多数难治性非病变性TLE患者可提供较可靠的致痫源定侧信息。     

颞叶癫痫与杏仁核硬化

难治性颞叶癫痫约65％—70％存在一侧海马硬化,但大多数伴有杏仁核硬化现象。颞叶癫痫包括海马——杏仁核硬化型和单纯杏仁核硬化型,单纯杏仁硬化的患者临床缺乏小儿期脑损伤史,记忆损害程度轻,其预后良好。MR是检测海马硬化和杏仁核硬化敏感可靠的方法,海马加杏仁核测量可达到93％的术前定位定侧准确率。     

颞叶癫痫的影像诊断

结合文献从计算机体层摄影（CT）、磁共振检查（MRI）和磁共振波谱分析（MRS），以及SPECT、PET、FMRI，介绍了近年来诊断颞叶癫痫（TLE）的进展。CT扫描对颅内较大病变和梗塞灶的发现具有高度敏感性，尤为钙化灶的发现优于MRI。MRI常能最精细地发现颞叶癫痫病人的脑结构灶病变．尤其是能准确地诊断出海马硬化，在他像或行FLAIR系列像上信号增强，阳性率可达60％～100％。MRS能测定出活体脑内代谢产物的分布，     

弥散张量成像在颞叶癫痫中的研究进展

颞叶癫痫(temporal lobe epilepsy,TLE)是临床最常见的难治性癫痫类型,海马硬化(hippocampus sclerosis,HS)是其最常见的病理改变.目前有多种新兴的多模态神经影像技术已用于TLE的临床定位、定侧及基础病理生理机制研究.弥散张量成像(diffusion tensor imaging,DTI)是近年来兴起的一项无创的可重复的MRI新技术,它能敏感地显示微观组织特征,并能够描述出脑各个部位结构的功能联系.本文就DTI技术在TLE中的研究进展综述如下.     

颞叶癫痫MR海马容积测量

目的：测量正常成人及颞叶癫痫病人海马体积，讨论其在颞叶癫痫（ＴＬＥ）致痫灶定侧中价值。方法：本组包括５２例正常成人和２６例颞叶癫痫病人，后者有２２例为顽固性癫痫。均作垂直于海马轴的冠状位ＳＥ序列Ｔ１加权像、ＴｕｒｂｏＳＥＴ２加权像，测量颞叶、海马体积和颞角、环池宽度，肉眼观察Ｔ２加权像海马信号强度改变。采用海马体积绝对值对ＴＬＥ定侧。结果：获取了正常成人海马体积。２２例ＴＬＥ海马体积缩小，其中３例为双侧性；６例海马硬化经手术、病理证实，１例体积正常且致痫灶位于海马周围者海马硬化轻。３例ＴＬＥ病人同侧前颞叶萎缩；部分ＴＬＥ病侧颞角、环池宽度增加；萎缩明显的海马Ｔ２加权像信号弥漫性增高。结论：海马体积缩小、Ｔ２加权像信号弥漫性增高是海马硬化萎缩的直接征象，与病变严重程度、致痫灶在颞叶的部位有关。前颞叶萎缩和颞角、环池增宽是海马硬化的辅助征象     

局灶性难治性颞叶癫痫全脑葡萄糖代谢特点

目的 探讨局灶性难治性颞叶癫痫全脑葡萄糖代谢特点。方法 回顾性分析2017年1~12月行发作间期18FDG-PET/CT检查的23例局灶性难治性颞叶癫痫的影像学资料。将PET图像导入MIM neuro软件,软件自动分析癫痫病人葡萄糖代谢水平与正常人群葡萄糖代谢的差异,各脑区差异结果以Z-Score值显示,分析颞叶癫痫病人全脑葡萄糖代谢特点。结果 术后病理为脑皮质发育不良22例,节细胞胶质瘤1例;病灶位于左侧颞叶16例,右侧颞叶7例。除颞叶呈葡萄糖低代谢改变外,还存在同侧海马、海马旁回、岛叶、杏仁核、颞叶岛盖以及双侧小脑半球葡萄糖代谢不同程度减低;对侧颞叶、额叶、顶叶、顶上小叶以及角回葡萄糖代谢不同程度增高。结论 颞叶癫痫具有一定葡萄糖代谢特点,其特定的葡萄糖代谢特点有助于更加精准的癫痫术前定位及其病理特征的分析。     

MRI与PET在颞叶癫痫中定位价值的比较

目的比较MRI及FDG-PET在颞叶癫致灶定位中的价值,探讨癫外科术前定位的方法以及手术预后的判断.方法以手术后癫控制状况为标准,对30例颞叶癫患者的术前MRI和FDG-PET的结果进行比较,分析MRI及PET各自在癫致灶定位中的价值.结果MRI有良好的脑结构分辨能力,对于症状性癫 的定位价值高,当MRI显示海马硬化时,对致灶定位的意义大,术后癫发作完全控制的可能性大.发作间期PET对于颞叶癫定位的敏感性高于MRI,但PET低代谢的范围往往超过致灶.与PET的目测方法比较,PET半定量分析并不能提高致灶定位的准确性及对手术效果的预测.结论MRI与PET检查结合可以提高致灶定位的准确性及对手术效果的预测,减少颅内记录的应用.     

颞叶癫(癎)的影像诊断

结合文献从计算机体层摄影(CT)、磁共振检查(MRI)和磁共振波谱分析(MRS),以及SPECT、PET、FMRI,介绍了近年来诊断颞叶癫(癎)(TLE)的进展.CT扫描对颅内较大病变和梗塞灶的发现具有高度敏感性,尤为钙化灶的发现优于MRI.MRI常能最精细地发现颞叶癫(癎)病人的脑结构灶病变,尤其是能准确地诊断出海马硬化,在T2像或行FLAIR系列像上信号增强,阳性率可达60%～100%.MRS能测定出活体脑内代谢产物的分布,是与癫(癎)灶生物化学改变密切相关的.在TLE病人采用MRS技术,可测出NAA峰值的降低和/或Cr,Cho峰值的升高,临床上常以NAA/Cr,Cho的比值来作为TLE的定侧指标.还简述了SPECT、PET和fMRI对诊断的价值.     

阿尔茨海默病~(18)F-FDG PET显像诊断的研究

目的 探讨阿尔茨海默病（AD）脑葡萄糖代谢及其18F-脱氧葡萄糖正电子发射计算机断层扫描（18F-FDG PET）显像的影像学特征和PET诊断标准。方法 静脉注射18F-FDG后行脑断层显像,检查13例 AD、13例非AD痴呆及13例正常人。获得纹状体、丘脑、黑质、顶叶、颞叶、额叶、枕叶、海马单位面积放射性计数与小脑计数的比值（Rcl/cb）,进行半定量分析,并与MR进行对照。结果AD患者PET异常率为100％,MR异常者占10/13。PET显像特征:①对称性双侧颞顶叶及海马伴额叶或枕叶代谢减低占9例（9/13）;②双侧颞叶对称性代谢减低伴海马或额叶代谢下降占3例（3/13）;③双顶叶对称性代谢降低1例（1/13）。12例（12/13）非AD痴呆表现为不对称、多发性代谢降低,降低区位于黑质、纹状体、丘脑及脑皮质区,MR异常率为11/13。结论 在除外脑内结构特异性损害基础上,PET发现对称性双颞顶叶、海马或颞叶、顶叶,伴或不伴枕叶、额叶代谢下降,可诊断AD。PET对AD早期诊断及鉴别诊断具有临床意义。     

Comparison of the intracarotid amobarbital procedure and interictal cerebral 18-fluorodeoxyglucose positron emission tomography scans in refractory temporal lobe epilepsy.

The relationship between interictal focal hypometabolism determined by 18-fluorodeoxyglucose positron emission tomography (FDG-PET) scans and memory function with the intracarotid amobarbital procedure (IAP) was evaluated in 23 patients with temporal lobe epilepsy. All patients underwent prolonged EEG/video monitoring. The epileptogenic focus was defined by interictal epileptiform discharges and ictal onsets. All 23 patients had recorded seizures arising exclusively from one temporal lobe. PET showed temporal lobe hypometabolism ipsilateral to the epileptogenic focus in 86% (20 of 23) of patients; IAP showed impaired memory of the hemisphere of seizure onset in 65% (15 of 23). Sixty-five percent (13 of 20) of patients with focal hypometabolism had ipsilateral memory impairment. Memory impairment contralateral to the hypometabolic zone was not observed. Ninety-five percent (22 of 23) of patients demonstrated functional impairment by either PET or IAP (or both) on the epileptogenic side.     

Is 11C-flumazenil PET superior to 18FDG PET and 123I-iomazenil SPECT in presurgical evaluation of temporal lobe epilepsy?

OBJECTIVE: To determine the contribution of 18FDG PET, 11C-flumazenil PET, and 123I-iomazenil SPECT to the presurgical evaluation of patients with medically intractable complex partial seizures. METHODS: Presurgical evaluation was performed in 23 patients, who were considered candidates for temporal lobe resective surgery (14 females and nine males with a median age of 34 (range 13 to 50) years). The presurgical diagnosis was based on seizure semiology as demonstrated with ictal video recording, ictal and interictal scalp EEG recordings, and MRI. RESULTS: Eighteen patients had convergent findings in clinical semiology, interictal and ictal EEG with scalp and sphenoidal electrodes, and MRI that warranted surgery without depth EEG (DEEG). In five patients with insufficient precision of localisation, DEEG with intracerebral and subdural electrodes was performed. MRI showed abnormalities in 22 out of 23 patients. Of these 22, 18 had mesial temporal sclerosis. This was limited to the mesial temporal lobe in four and more widespread in the temporal lobe in 14 patients. In one patient only enlargement of the temporal horn was found and in three others only white matter lesions were detected. 18FDG PET showed a large area of glucose hypometabolism in the epileptogenic temporal lobe, with an extension outside the temporal lobe in 10 of 23 patients. Only in one of these patients DEEG showed extratemporal abnormalities that were concordant with a significant extratemporal extension of hypometabolism in 18FDG PET. 18FDG PET was compared with the results of scalp EEG: in none of the patients was an anterior temporal ictal onset in scalp EEG related to a maximum hypometabolism in the mesial temporal area. By contrast, the region of abnormality indicated by 11C-flumazenil PET was much more restricted, also when compared with DEEG findings. Extension of abnormality outside the lobe of surgery was seen in only two patients with 11C-flumazenil and was less pronounced compared with the intratemporal abnormality. Both 18FDG PET and 11C-flumazenil PET reliably indicated the epileptogenic temporal lobe. Thus these techniques provide valuable support for the presurgical diagnosis, especially in patients with non-lesional MRI or non-lateralising or localising scalp EEG recordings. In those patients in whom phase 1 presurgical evaluation on the basis of classic methods does not allow a localisation of the epileptogenic area, PET studies may provide valuable information for the strategy of the implantation of intracranial electrodes for DEEG. Previous studies have suggested that 11C-flumazenil binding has a closer spatial relationship with the zone of ictal onset than the area of glucose hypometabolism, but this study suggests rather that the decrease in the 11C-flumazenil binding simply reflects a loss of neurons expressing the benzodiazepine-GABA receptor. 11C-flumazenil PET did not prove to be superior to 18FDG PET. CONCLUSION: In 21 patients sufficient material was obtained at surgery for a pathological examination. In 17 mesial temporal sclerosis, in one an oligodendroglioma grade B, in another a vascular malformation and in two patients no abnormalities were found. Although all 21 patients with pathological abnormality showed hypometabolic zones with 18FDG PET and a decreased uptake in 11C-flumazenil binding, there was no strong correlation between pathological diagnosis and functional abnormal areas in PET. Grading of medial temporal sclerosis according to the Wyler criteria showed no correlation with the degree of hypometabolism in either 18FDG or 11C-flumazenil PET. The interictal 123I-iomazenil SPECT technique was highly inaccurate in localising the lobe of surgery.     

Temporal lobe epilepsy with bilateral seizure origin studied by [18F]FDG-positron emission tomography

Nine patients who underwent presurgical evaluation because of medically refractory temporal lobe epilepsy (TLE) showed either unilateral, although alternating in side, or bilateral simultaneous seizure onsets in both temporal lobes (TL). EEG recordings with semi-invasive foramen ovale electrodes revealed in seven patients a predominance of seizure onset in one TL of between 50% and 88%. In two patients the majority of seizures originated simultaneously in both TL. In four patients a unilateral selective amygdalohippocampectomy resulted in a good to excellent seizure outcome without noteworthy memory deficits and confirmed the preoperative lateralization of the primary epileptogenic focus by interictal ¹⁸F-fluorodeoxyglucose positron emission tomography (PET). Five patients were rejected from surgery due to strong bilaterality of their epilepsy and/or divergent presurgical findings. PET contributed to the decision of whether surgery should be performed: all patients who underwent surgery had a unilateral TL hypometabolism which was concordant with the findings of other tests. Patients in whom surgery was denied had either bilateral temporal hypometabolism or the PET findings were discordant with other results obtained during the presurgical evaluation.     

Correlation of severity of FDG-PET hypometabolism and interictal regional delta slowing in temporal lobe epilepsy

PURPOSE: We investigated the association of severity of hypometabolism detected by positron emission tomography (PET) with [(18)F]fluorodeoxyglucose (FDG) and persistence of interictal EEG focal slowing in patients with refractory temporal lobe epilepsy. METHODS: Eighty temporal lobes of 40 consecutive patients with intractable temporal lobe epilepsy (mean age, 43.5 years) were studied. All patients underwent video-EEG monitoring, magnetic resonance imaging (MRI), and FDG-PET. Patients with either normal MRI or with unilateral mesial temporal sclerosis, but no other structural abnormality, were included. Interictal EEG delta slowing was graded as none, infrequent (one episode or less/hour), intermediate (more than one episode/hour), or continuous. PET hypometabolism was graded as none, mild, moderate, or severe. RESULTS: The severity of temporal lobe hypometabolism with PET was significantly correlated with the amount of delta activity in the interictal EEG, independent of MRI findings (Spearman r = 0.46; p < 0.0005). CONCLUSIONS: This observation suggests related underlying pathophysiologic mechanisms for metabolic and electrical dysfunction in temporal lobe epilepsy.     

Identification of Frontal Lobe Epileptic Foci in Children Using Positron Emission Tomography

Summary: Purpose: Presurgical evaluation for intractable frontal lobe epilepsy (FLE) is difficult and invasive, partly because anatomic neuroimaging studies with computed tomography (CT) and magnetic resonance imaging (MRI) typically do not show a discrete lesion. In adult patients with FLE, functional neuroimaging of glucose metabolism with positron emission tomography (PET) is less sensitive in detecting focal metabolic abnormalities than in temporal lobe epilepsy (TLE). Comparable data on children with FLE are not available. Methods: We used high-resolution PET scanning of glucose metabolism to evaluate 13 children (age 17 months to 17 years; mean age 9.5 years) with intractable FLE being considered for surgical treatment. Only children with normal CT and MRI scans were included. Results: Hypometabolism including the frontal lobe was evident in 12 of the 13 children, was unilateral in 11 of 13, and was restricted to the frontal lobe in 8 of 13. One child showed bilateral frontal cortex hypometabolism and another had anictal PET scan demonstrating unilateral frontal cortex hyper-metabolism surrounded by hypometabolism. Additional hypo–metabolic areas outside the frontal cortex were observed in 5 children in parietal and/or temporal cortex. Localization of seizure onset on scalp EEG was available in 10 children and corresponded to the location of frontal lobe PET abnormality in 8. However, in 4 of the 10 children, the extent of hypometabolism exceeded the epileptogenic region indicated by ictal EEG. In 2 of the 13 children, the abnormality evident on EEG was more extensive than that evident on PET. In the remaining 3 children for whom only interictal EEG data were available, the PET foci did not correspond in location to the interictal EEG abnormalities. In 11 of the 13 children, the presumed region of seizure onset in the frontal lobe, as based on analysis of seizure semiology, corresponded to the locations of frontal lobe glucose metabolism abnormalities. Conclusions: Although high-resolution PET appears to be very sensitive in localizing frontal lobe glucose metabolic abnormalities in children with intractable FLE and normal CT/ MRI scans, the significance of extrafrontal metabolic disturbances requires further study; these may represent additional epileptogenic areas, effects of diaschisis, seizure propagation sites, or secondary epileptogenic foci.     

Contralateral temporal hypometabolism on positron emission tomography in temporal lobe epilepsy

Introduction — No detailed case studies report lateralised hypometabolism on positron emission tomography (PET) contralateral to the epileptogenic focus in temporal lobe epilepsy (TLE). Material and methods — We performed ¹⁸F fluorodeoxyglucose (FDG) PET in two intractable TLE patients. Results — One had right temporal interictal spikes on electroencephalography (EEG) and a right medial temporal lobe lesion on magnetic resonance imaging (MRI). FDG-PET showed decreased uptake in the left temporal lobe. Right temporal ictal onset, with bilateral interictal epileptiform activity, occurred on intracranial EEG. He is seizure free after right temporal lobectomy and ganglioglioma resection. The second had right temporal lobe interictal and ictal EEG activity. MRI demonstrated right anteriomedial temporal increased T2 signal. Neuropsychology revealed bilateral cognitive dysfunction. FDG-PET showed left anterior temporal and lateral frontal hypometabolism. He is seizure free after right temporal lobectomy. Conclusion — These findings suggest that regional uptake asymmetry on FDG-PET may be give misleading lateralising information in TLE.     

18F-FDG-PET在颞叶癫痫灶定位中的应用

目的 介绍发作间期 18F-FDG-PET进行颞叶癫痫灶定位的方法,探讨发作间期18F-FDG-PET在颞叶癫痫灶定位中的价值.方法 回顾性分析术前行 18F-FDG-PET检查、手术后随访效果达到 Engle Ⅰ级的82例颞叶癫痫患者的临床资料,对 18F-FDG-PET在颞叶癫痫灶中定位敏感率和特异性进行分析,并与脑电图监测和MRI进行比较.结果 发作间期 18F-FDG-PET检查中癫痫灶表现为低代谢灶,其中68例位于癫痫灶侧颞叶或以颞叶为主合并其它区域,9例位于癫痫灶侧颞叶以外,5例未见低代谢灶.18F-FDG-PET对癫痫灶定位诊断准确率为82.9%(68/82),显著优于MRI和脑电图(P＜0.05),且在MRI阴性和需要埋置电极进行脑电图检查定位的患者中分别有77.4%(41/53)和75%(15/20)可以达到准确的定位癫痫灶.病理阳性者18F-FDG-PET定位准确率显著高于病理阴性者(P＜0.05).结论 18F-FDG-PET定位颞叶癫痫灶具有高敏感性、高特异性的特点,对MRl阴性和需要埋置电极进行检查的颞叶癫痫灶也有良好的定位价值,合理的应用还可能进一步提高结果.     

Correlation of hippocampal glucose oxidation capacity and interictal FDG-PET in temporal lobe epilepsy

PURPOSE: Interictal [18F]fluorodeoxyglucose (FDG) positron emission tomography (PET) demonstrates temporal hypometabolism in the epileptogenic zone of 60-90% of patients with temporal lobe epilepsy. The pathophysiology of this finding is still unknown. Several studies failed to show a correlation between hippocampal FDG-PET hypometabolism and neuronal cell loss. Because FDG is metabolized by hexokinase bound to the outer mitochondrial membrane, we correlated the glucose-oxidation capacity of hippocampal subfields obtained after surgical resection with the corresponding hippocampal presurgical FDG-PET activity. METHODS: In 16 patients with electrophysiologically confirmed temporal lobe epilepsy, we used high-resolution respirometry to determine the basal and maximal glucose-oxidation rates in 400-microm-thick hippocampal subfields obtained after dissection of human hippocampal slices into the CA1 and CA3 pyramidal subfields and the dentate gyrus. RESULTS: We observed a correlation of the FDG-PET activity with the maximal glucose-oxidation rate of the CA3 pyramidal subfields (rp = 0.7, p = 0.003) but not for the regions CA1 and dentate gyrus. In accordance with previous studies, no correlation of the FDG-PET to the neuronal cell density of CA1, CA3, and dentate gyrus was found. CONCLUSIONS: The interictal hippocampal FDG-PET hypometabolism in patients with temporal lobe epilepsy is correlated to the glucose-oxidation capacity of the CA3 hippocampal subfield as result of impaired oxidative metabolism.     

Metabolic changes of subcortical structures in intractable focal epilepsy

PURPOSE: Intractable focal epilepsy is commonly associated with cortical glucose hypometabolism on interictal 2-deoxy-2[18F]-fluoro-D-glucose (FDG) positron emission tomography (PET). However, subcortical brain structures also may show hypometabolism on PET and volume changes on magnetic resonance imaging (MRI) studies, and these are less well understood in terms of their pathophysiology and clinical significance. In the present study, we analyzed alterations of glucose metabolism in subcortical nuclei and hippocampus by using FDG-PET in young patients with intractable epilepsy. METHODS: Thirty-seven patients (mean age, 7.5 years; age range, 1-27 years) with intractable frontal (n = 23) and temporal (n = 14) lobe epilepsy underwent FDG-PET scanning as part of their presurgical evaluation. Normalized glucose metabolism was measured in the thalamus and caudate and lentiform nuclei, as well as in hippocampus, both ipsi- and contralateral to the epileptic focus, and correlated with duration and age at onset of epilepsy, presence or absence of secondary generalization, location of the epileptic focus, and extent of cortical glucose hypometabolism. RESULTS: Long duration of epilepsy was associated with lower glucose metabolism in the ipsilateral thalamus and hippocampus. Duration of epilepsy was a significant predictor of ipsilateral thalamic glucose metabolism in both temporal and frontal lobe epilepsy. Presence of secondarily generalized seizures also was associated with lower normalized metabolism in the ipsilateral thalamus and hippocampus. Extent of cortical hypometabolism did not correlate with subcortical metabolism, and glucose metabolism in the caudate and lentiform nuclei did not show any correlation with the clinical variables. CONCLUSIONS: The findings suggest that metabolic dysfunction of the thalamus ipsilateral to the seizure focus may become more severe with long-standing temporal and frontal lobe epilepsy, and also with secondary generalization of seizures.     

难治性癫癎MRJ颞极信号特点与癫癎的相关性分析

目的探讨难治性癫癎MRI颞极信号特点与致癎区相关性。方法回顾性分析339例难治性癫癎病人MRI颞极信号特点。根据癫癎发作起始区将研究对象分为颞叶癫癎、额叶癫癎、顶叶癫癎、枕叶癫癎、岛叶癫癎、多脑叶癫癎等6类。结果颞极信号异常187例,颞极信号异常侧别与致癎区侧别一致率达98．93％,颞极信号异常与癫癎类型或致癎区有关（χ2=311．339,P〈0．001）。与颞叶外癫癎比较,颢极信号异常更常见于颞叶癫癎。结论在各类癫癎中均可出现MR／颞极信号异常,但更常见于颞叶癫癎。颞极信号异常侧常与致癎区侧别一致．特别是颞叶癫癎。