FDG-PET/MRI coregistration and diffusion-tensor imaging distinguish epileptogenic tubers and cortex in patients with tuberous sclerosis complex: a preliminary report

PURPOSE: Patients with tuberous sclerosis complex (TSC) are potential surgical candidates if the epileptogenic region(s) can be accurately identified. This retrospective study determined whether FDG-PET/MRI coregistration and diffusion-tensor imaging (DTI) showed better accuracy in the localization of epileptogenic cortex than structural MRI in TSC patients. METHODS: FDG-PET/MRI coregistration and/or DTI for apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were utilized in 15 TSC patients. Presurgery scalp EEG and postsurgery seizure control identified epileptogenic tubers (n = 27) and these were compared with nonepileptogenic tubers (n = 204) for MRI tuber volume, volume of FDG-PET hypometabolism on MRI coregistration, DTI, ADC, and FA values. RESULTS: Compared with nonepileptogenic tubers, epileptogenic regions had increased volume of FDG-PET hypometabolism (p < 0.0001), and increased ADC values in subtuber white matter (p < 0.0001). In contrast, the largest MRI identified tuber (p = 0.046) and decreased FA values (p = 0.58) were less accurate in identifying epileptogenic regions. Larger volumes of FDG-PET hypometabolism correlated positively with increased ADC values (p = 0.029), and localized to areas of cortical dysplasia adjacent to the tuber in four cases. CONCLUSIONS: Larger volumes of FDG-PET hypometabolism relative to MRI tuber size and higher ADC values identified epileptogenic tubers and adjoining cortex containing cortical dysplasia in TSC patients with improved accuracy compared with largest tuber by MRI or lowest FA values. Used in conjunction with ictal scalp EEG and interictal magnetoencephalography, these newer neuroimaging techniques should improve the noninvasive evaluation of TSC patients with intractable epilepsy in distinguishing epileptogenic sites for surgical resection.     

部分性癫(癎)二例发作间期同步应用脑电图-功能磁共振成像定位致(癎)灶

目的 探讨部分性癫(癎)(癎)性放电相关血氧水平依赖(BOLD)信号的分布规律,为进一步研究该病的发病机制、脑功能变化奠定基础.方法 采用同步脑电图一功能磁共振成像(EEG-fMRI)技术,对2例部分性癫(癎)患者进行发作问期(癎)性放电相关BOLD变化的研究,探讨该病发作间期(癎)性放电相关BOLD信号与临床脑电图定位脑区的相互关系.结果 2例患者的临床脑电图定位脑区均出现了最大激活信号,其中1例在该区域有2处显著激活;在该区对侧相应脑区也有较弱的激活信号出现.结论 部分性癫(癎)(癎)性放电相关BOLD反应以(癎)性放电脑区为主,但其对侧同源脑区也有较弱的激活信号,fMRI激活信号与脑电活动之间有着很好的对应关系.     

Hippocampal and thalamic diffusion abnormalities in children with temporal lobe epilepsy

PURPOSE: Previous studies using diffusion MRI in patients with temporal lobe epilepsy have shown abnormal water diffusion in the hippocampus. Because thalamus and lentiform nuclei are considered important for the regulation of cortical excitability and seizure propagation, we analyzed diffusion tensor imaging (DTI) abnormalities in these subcortical structures and in hippocampus of children with partial epilepsy with and without secondary generalization. METHODS: Fourteen children with partial epilepsy involving the temporal lobe underwent MRI including a DTI sequence. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were obtained in the hippocampus, thalamus, and lentiform nucleus, and compared with DTI data of 14 control children with no epilepsy, as well as glucose positron emission tomography (PET) findings. RESULTS: Decreased FA (p < 0.001) and increased ADC (p = 0.003) values were found in the hippocampi ipsilateral to the seizure focus. Significant FA decreases (p = 0.002) also were seen in the contralateral hippocampi, despite unilateral seizure onset and excellent surgical outcome in patients who underwent surgery. ADC values showed a trend for increase in the thalami ipsilateral to the epileptic focus in the seven children with secondarily generalized seizures (p = 0.09). No group differences of ADC or FA were found in the lentiform nuclei. The DTI variables did not correlate with regional glucose metabolism in any of the structures analyzed. CONCLUSIONS: Increased ADC values in hippocampus can assist in lateralizing the seizure focus, but decreased FA in the contralateral hippocampus suggests that it too may be dysfunctional despite unilateral seizure onset. Less-robust thalamic abnormalities of water diffusion in patients with secondarily generalized seizures suggest secondary involvement of the thalamus, perhaps due to recruitment of this structure into the epileptic network; however, this must be confirmed in a larger population. DTI appears to be a sensitive method for detection abnormalities in children with partial epilepsy, even in structures without apparent changes on conventional MRI.     

High-resolution diffusion tensor imaging of the hippocampus in temporal lobe epilepsy

PURPOSE: To assess the quantitative diffusion characteristics of the hippocampus with high-resolution diffusion tensor imaging (DTI) in temporal lobe epilepsy (TLE). METHODS: Thirteen controls and seven unilateral TLE patients (six with hippocampal sclerosis, one with normal magnetic resonance imaging (MRI)) were scanned with DTI using a zonally magnified oblique multislice echo planar imaging (ZOOM-EPI) acquisition. Fractional anisotropy (FA) and mean diffusivity (MD) were measured in the hippocampi. RESULTS: The mean hippocampal MD ipsilateral to the seizure focus was higher than the contralateral MD in patients (p<0.05) and the mean MD in controls (p<0.001). Hippocampal FA ipsilateral to the seizure focus was lower than the mean FA in controls (p<0.05). MD asymmetry indexes were significantly different between the patient and control groups (p<0.01). All six individual HS patients had ipsilateral hippocampal MD >or=2 standard deviations (S.D.) above the control mean. The patient with normal structural MRI had bilaterally low hippocampal FA and high MD. DISCUSSION: High-resolution DTI identifies lateralizing abnormalities of MD and FA in TLE patients. This quantitative data on hippocampal integrity may assist in evaluating TLE patients with normal MRI, and in longitudinal studies.     

Neuroimaging in epilepsy: diagnostic strategies in partial epilepsy

The diagnostic evaluation of the patient with partial or localization-related epilepsy is designed to identify treatment strategies that will permit the individual to be seizure-free. The use of magnetic resonance imaging (MRI) has been pivotal in elucidating the presence of an epileptogenic pathological alteration that may coexist with the site of seizure onset. There are compelling data that MRI is of significant diagnostic and prognostic importance in patients with partial epilepsy. Patients with MRI-negative partial epilepsy may be candidates for additional neuroimaging techniques including positron emission tomography, MR spectroscopy, and single photon emission tomography. Contemporary innovations with peri-ictal imaging may allow identification of the epileptogenic zone in patients with normal MRI scans. This discussion will focus on the management of the adult patient with seizures and epilepsy, emphasizing the neuroimaging evaluation and treatment of patients with medically refractory seizure disorders.     

Parahippocampal epilepsy with subtle dysplasia: A cause of “imaging negative” partial epilepsy

Purpose: Lesion‐negative refractory partial epilepsy is a major challenge in the assessment of patients for potential surgery. Finding a potential epileptogenic lesion simplifies assessment and is associated with good outcome. Here we describe imaging features of subtle parahippocampal dysplasia in five cases that were initially assessed as having imaging‐negative frontal or temporal lobe epilepsy. Methods: We analyzed the clinical and imaging features of five patients with seizures from the parahippocampal region. Results: Five patients had subtle but distinctive magnetic resonance imaging (MRI) abnormalities in the parahippocampal gyrus. This was a unilateral signal abnormality in the parahippocampal white matter extending into gray matter on heavily T₁‐ and T₂‐weighted images with relative preservation of the gray–white matter boundary on T₁‐weighted volume sequences. Only one of these patients had typical electroclinical unilateral temporal lobe epilepsy (TLE); one mimicked frontal lobe epilepsy, two showed bitemporal seizures, and one had unlocalized partial seizures. All have had surgery; four are seizure‐free (one has occasional auras only, follow‐up 6 months to 10 years), and one has a >50% seizure reduction. Histopathologic evaluation suggested dysplastic features in the surgical specimens in all. Discussion: In patients with lesion‐negative partial epilepsy with frontal or temporal semiology, or in cases with apparent bitemporal seizures, subtle parahippocampal abnormalities should be carefully excluded. Recognizing the MRI findings of an abnormal parahippocampal gyrus can lead to successful surgery without invasive monitoring, despite apparently incongruent electroclinical features.     

Seizure outcome after anterior temporal lobectomy and its predictors in patients with apparent temporal lobe epilepsy and normal MRI

PURPOSE: Very little reliable information is available regarding the role of anterior temporal lobectomy (ATL), optimal presurgical evaluation strategy, post-ATL seizure outcome, and the factors that predict the outcome in patients with medically refractory temporal lobe epilepsy (TLE) and normal high-resolution magnetic resonance imaging (MRI). To be cost-effective, epilepsy surgery centers in developing countries will have to select candidates for epilepsy surgery by using the locally available technology and expertise. METHODS: We reviewed the electroclinical and pathological characteristics and seizure outcome of 17 patients who underwent ATL for medically refractory TLE after being selected for ATL based on a noninvasive selection protocol without the aid of positron emission tomography (PET) or single-photon emission computed tomography (SPECT), despite a normal preoperative high-resolution MRI. RESULTS: Seven (41%) patients achieved an excellent seizure outcome; five of them were totally seizure free. An additional five (29%) patients had >75% reduction in seizure frequency. The following pre-ATL factors predicted an excellent outcome: antecedent history of febrile seizures, strictly unilateral anterior temporal interictal epileptiform discharges (IEDs), and concordant type 1 ictal EEG pattern. All the five patients with pathologically verified hippocampal formation neuronal loss were seizure free. The presence of posterior temporal, bilateral temporal, and generalized IEDs portended unfavorable post-ATL seizure outcome. CONCLUSIONS: A subgroup of patients destined to have an excellent post-ATL outcome can be selected from MRI-negative TLE patients by using history and scalp-recorded interictal and ictal EEG data. The attributes of these patients are antecedent history of febrile seizures, strictly unilateral anterior IEDs, and concordant type 1 ictal EEG pattern.     

脑磁图对难治性癫痫致痫区定位价值

目的探讨脑磁图癫痫定位技术对难治性癫痫致痫区定位的价值。方法回顾性分析难治性癫痫病人58例,术前行视频头皮脑电图、磁共振、脑磁图、颅内埋藏电极皮层脑电图等检查,综合评估确定致痫灶的位置。根据综合评估致痫区制定手术方案并实施,随访并判定疗效。根据脑磁图癫痫定位和综合评估致痫区吻合度分为3组,Ⅰa组：完全吻合一两区域中心位置在1cm以内,Ⅰb组：基本吻合一两区域中心位置在1～3cm;Ⅱ组：不吻合一两区域中心位置在3cm以外或其他。统计分析各组间疗效的差异。结果本组总有效率为77．6％（45／58）,其中癫痫完全消失18例;Ⅰa、Ⅰb组手术疗效无明显差异,但Ⅰ组手术疗效明显优于Ⅱ组。结论脑磁图癫痫定位是难治性癫痫术前评估的重要方法之一,当脑磁图癫痫定位和术前综合评估致痫区基本一致时,手术疗效相对较好。     

Diffusion tensor imaging in late posttraumatic epilepsy

PURPOSE: The main objective of this study was to use diffusion tensor imaging (DTI) to search and quantify the extent of abnormality beyond the obvious lesions seen on the T2 and fluid-attenuation inversion recovery (FLAIR) magnetic resonance images in patients with chronic traumatic brain injury (TBI) with and without epilepsy. METHODS: DTI was performed on 23 chronic TBI patients (with late posttraumatic epilepsy, n=14; without epilepsy, n=9) and 11 age-matched controls. The ratios of fractional anisotropy (FA) and mean diffusivity (MD) between the regions of interest beyond the T2/FLAIR-visualized abnormality and the corresponding contralateral normal-appearing region were calculated. FA and MD ratios were compared for relative changes in these parameters among the TBI subjects with and without epilepsy and controls. Tissue volumes exhibiting abnormalities on DTI also were measured in these patients. RESULTS: The mean regional FA ratio was significantly lower, whereas the mean regional MD value was higher in patients with TBI compared with controls. The mean regional FA ratio was significantly lower in TBI patients with epilepsy (0.57+/-0.059) than in those without epilepsy (0.68+/-0.039). Although the regional MD ratio was higher in TBI patients with epilepsy (1.15+/-0.140) relative to those without epilepsy (1.09+/-0.141), the difference did not reach statistical significance. The tissue volume with low FA value also was found to be higher in TBI patients with epilepsy than without. CONCLUSIONS: Severity of injury as predicted by the DTI-derived increased volume of microstructure damage is associated with delayed posttraumatic epilepsy in TBI patients. These findings could be valuable in predicting epileptogenesis in patients with chronic TBI.     

EEG-fMRI study of the interictal epileptic activity in patients with partial epilepsy

PURPOSE: To investigate Blood Oxygen Level Dependent (BOLD) responses to interictal epileptic discharges (IEDs) during EEG-correlated functional MRI (EEG-fMRI) in patients with partial epilepsy. METHODS: We studied eight patients who had a diagnosis of partial epilepsy and active spiking on routine scalp EEG recording. Sessions of continuous EEG-fMRI were recorded, and spikes (identified after online artifact removal) were used as events in the fMRI analysis. Regions of BOLD signal change in response to interictal epileptic discharge were assessed and epileptogenic zone localization was electroclinically identified. RESULTS: Eight patients with partial epilepsy were recruited (6 males, 2 females, mean age 18.5, mean onset age range 0.5-29). Two who underwent EEG-fMRI were excluded from further analysis: one due to absence of epileptic discharges, the other due to excessive head motion. Eight sessions of EEG-fMRI scanning in 6 patients were obtained: 6 with activation and deactivation, one with activation only, and one with deactivation only. Focal activations corresponding to electroclinical localization occurred in 7 sessions, 5 of which were maximal. CONCLUSIONS: Maximally activated areas detected by EEG-fMRI in patients with partial epilepsy appear to be concordant with epileptogenic areas as defined by electroclinical localization data. In most patients with focal epilepsy, positive BOLD responses seem to be mainly in epileptogenic zones and the corresponding contralateral areas. Responses to deactivation seem less associated with IEDs. So EEG-fMRI is a useful tool to study the pathophysiological mechanisms of epilepsy and may assist in presurgical evaluation of epilepsy.     

Diffusion tensor imaging findings and their correlation with neuropsychological deficits in patients with temporal lobe epilepsy and interictal psychosis

PURPOSE: To examine frontotemporal white-matter integrity in patients with temporal lobe epilepsy (TLE) and interictal psychosis. METHOD: Patients with TLE and interictal psychosis (IP; n = 20) were compared with age-matched TLE patients without psychosis (NIP; n = 20). Patients had either no focal lesions or hippocampal sclerosis on conventional MRI. Complete diffusion tensor imaging (DTI) data were available in 18 IP and 20 NIP patients. A region-of-interest (ROI) approach was used to determine the DTI measures, fractional anisotropy (FA) and mean diffusivity (MD), in the middle frontal and middle temporal gyri. The relation between the DTI measures and neuropsychological tests previously identified as impaired in the IP group was examined. RESULTS: The IP group had significantly lower FA values in both frontal and temporal regions and significantly higher MD in bilateral frontal regions. We found that performance on some neuropsychological tests was significantly related to frontotemporal FA reductions. CONCLUSIONS: Our findings suggest that subtle abnormalities in the frontotemporal white matter of patients with interictal psychosis may be undetectable on conventional MRI. These abnormalities may contribute to the cognitive deficits detected in these patients.     

Localizing value of alpha-methyl-L-tryptophan PET in intractable epilepsy of neocortical origin.

BACKGROUND: [(11)C] alpha-methyl-L-tryptophan (alpha-MTrp) has been developed as a tracer for the study of the synthesis of serotonin in the brain with PET. However, it has been shown that in pathologic conditions the tracer may reflect the activation of kynurenine metabolism. Increased levels of serotonin and quinolinic acid have been described in resected epileptogenic cortex, raising the possibility that alpha-MTrp can localize seizure foci in patients with intractable partial epilepsy. The authors assessed the uptake of alpha-MTrp in 18 patients (11 men, mean +/- SD age 27.1 +/- 10.1 years, range 13 to 54) with intractable partial epilepsy to correlate the PET findings with the epileptogenic area defined by electroclinical and neuroimaging data. METHOD: Seven patients with cortical dysplasia (CD) and 11 with partial epilepsy in which conventional MRI and fluorine-18-deoxyglucose ((18)FDG)-PET studies failed to detect any abnormality were studied. All underwent scalp EEG monitoring during the PET scan to exclude ictal events and estimate the interictal epileptic activity. RESULTS: In seven patients (39%; CD four and cryptogenic partial epilepsy three), PET showed focal increased uptake of alpha-MTrp corresponding to the epileptogenic area. alpha-MTrp uptake in the epileptic focus correlated with the frequency of interictal spikes (r = 0.7, p < 0.05). CONCLUSIONS: alpha-MTrp-PET may be of value in the localization of the epileptogenic area not only in patients with visible dysplastic lesions, but also in those with cryptogenic partial epilepsy.     

Correlation between language organization and diffusion tensor abnormalities in refractory partial epilepsy

PURPOSE: Atypical language organization is more frequently found in patients with refractory partial epilepsy than in healthy controls; however, the reasons for this are not well known. Here we assess the relation between language laterality index (LI) and white-matter tract changes. METHODS: Nine patients with refractory partial epilepsy were assessed with a 3-T GE scanner. Functional magnetic resonance imaging (fMRI) of language and diffusion tensor imaging (DTI) were acquired. For the fMRI, a noun-verb generation task was performed, all images were motion corrected, and activated pixels in classic language areas were counted. The DTI images were acquired in six standard directions with an initial non-diffusion-weighted scan. The "average anisotropy" was determined in a region of interest in the frontal lobe, temporal lobe, and parietal lobe white matter. An asymmetry index (AI) was calculated for language and DTI. Atypical language lateralization was diagnosed if the lateralization index (LI)-language was smaller than 0.4. RESULTS: Two of the nine patients had atypical language localization (LI-language, -0.6, and 0.3); both had left temporal DTI asymmetry (LI-DTI, -0.3 and -0.2). The remaining seven patients had typical language localization, and no marked DTI abnormalities. Asymmetry in temporal lobe DTI correlated with LI-language (r= 0.8; p = 0.006). CONCLUSIONS: Atypical language lateralization in patients with partial epilepsy may be associated with white-matter tract abnormalities.     

Surgical treatment for epilepsy

Nearly one-third of patients with newly diagnosed epilepsy will develop medically refractory seizure disorders. The initial response to antiepileptic drug therapy is highly predictive of long-term outcome. Patients with intractable epilepsy may have a progressive disorder that is medically, physically, and socially disabling. Surgical resection of the epileptogenic zone or lesional pathology, or both, may significantly reduce seizure tendency in selected patients. The present review supports the position that early and effective epilepsy surgery may not only render the patient with intractable partial epilepsy seizure-free, but also allow the individual to become a participating and productive member of society. Patients with surgically remediable epileptic syndromes should be identified early in the evaluation and treatment of their seizure disorders. Favorable candidates for focal cortical resection include individuals with medial temporal lobe epilepsy and partial seizures related to selected lesional pathology, e.g. primary brain tumor or vascular anomalies. In conclusion, surgical treatment of intractable partial epilepsy has been shown to compare favorably to antiepileptic drug therapy. Individuals rendered seizure-free may experience a significant improvement in quality of life. Patients who fail to respond to initial antiepileptic drug therapy should be “triaged” to a presurgical evaluation. Ictal semiology combined with structural magnetic resonance imaging and the electroclinical correlation may permit identification of candidates for early and effective surgical treatment.     

Spatial extent of neuronal metabolic dysfunction measured by proton MR spectroscopic imaging in patients with localization-related epilepsy

SUMMARY: PURPOSE: To assess the spatial extent of the decrease in the neuronal marker N-acetyl-aspartate (NAA) relative to creatine (Cr) in patients with localization-related epilepsy, and to assess clinical differences between patients with and without widespread NAA/Cr reduction. METHODS: We studied 51 patients with localization-related epilepsy. Patients were divided into three groups according to the EEG investigation: (a) temporal lobe epilepsy (TLE, n = 21), (b) extratemporal lobe epilepsy (extra-TLE, n = 20), and (c) multilobar epilepsy (patients with a wider epileptogenic zone, n = 10). We acquired proton magnetic resonance (MR) spectrocopic imaging (1H-MRSI) of temporal and frontocentroparietal regions in separate examinations for both patients and controls. NAA/Cr values 2 standard deviations below the mean of normal controls were considered abnormal. RESULTS: Twenty-three (45%) patients including 12 with TLE had normal MR imaging including volumetric studies of the hippocampus. Forty-nine (96%) patients had low NAA/Cr, indicating neuronal dysfunction in either temporal and/or extratemporal 1H-MRSIs; 38% of patients with TLE and 50% of patients with extra-TLE also had NAA/Cr reduction outside the clinical and EEG-defined primary epileptogenic area. The NAA/Cr reduction was more often widespread in the multilobar group [six (60%) of 10] than in temporal or extratemporal groups [five (31%) of 16]. Nonparametric tests of (a) seizure duration, (b) seizure frequency, and (c) lifetime estimated seizures showed no statistically significant difference (p > 0.05) for TLE and extra-TLE patients with or without NAA/Cr reduction outside the seizure focus. CONCLUSIONS: Of patients with localization-related epilepsy, 40-50% have neuronal metabolic dysfunction that extends beyond the epileptogenic zone defined by clinical-EEG and/or the structural abnormality defined by MRI.     

Value of 3.0 T MR imaging in refractory partial epilepsy and negative 1.5 T MRI

BackgroundHigh-field 3.0 T MR scanners provide an improved signal-to-noise ratio which can be translated in higher image resolution, possibly allowing critical detection of subtle epileptogenic lesions missed on standard-field 1.0–1.5 T MRIs. In this study, the authors explore the potential value of re-imaging at 3.0 T patients with refractory partial epilepsy and negative 1.5 T MRI.MethodsWe retrospectively identified all patients with refractory partial epilepsy candidate for surgery who had undergone a 3.0 T MR study after a negative 1.5 T MR study. High-field 3.0 T MRIs were reviewed qualitatively by neuroradiologists experienced in interpreting epilepsy studies with access to clinical information. Relevance and impact on clinical management were assessed by an epileptologist.ResultsBetween November 2006 and August 2009, 36 patients with refractory partial epilepsy candidate for surgery underwent 3.0 T MR study after a 1.5 T MR study failed to disclose a relevant epileptogenic lesion. A potential lesion was found only in two patients (5.6%, 95% CI: 1.5–18.1%). Both were found to have hippocampal atrophy congruent with other presurgical localization techniques which resulted in omission of an invasive EEG study and direct passage to surgery.ConclusionsThe frequency of detection of a new lesion by re-imaging at 3.0 T patients with refractory partial epilepsy candidate for surgery was found to be low, but seems to offer the potential of a significant clinical impact for selected patients. This finding needs to be validated in a prospective controlled study.     

Comparison of modern diagnostic methods in children with intractable focal epilepsy

The basic aim of neuroimaging in children with intractable focal epilepsy is stablishing localization of epileptogenic zone. In this study 34 children (age 11-17 years) with intractable focal epilepsy were examined including: clinical history, physical examination, EEG, CT, MR, 99mTc-HMPAO SPECT. The hypoperfused region in interictal SPECT was concordant with clinical seizure characteristics in 22 children, with EEG in 13, with MR with 13 children. The localization of hyperperfused region in ictal SPECT was concordant with the clinical seizure characteristics in 9 from 10 examined children, with EEG in 7 and with MR in 8. The diagnostic value of estimation of the localization of epileptogenic zone in interictal SPECT (63 per cent) was comparable with the results of EEG (56 per cent) and MR (59 per cent), but ictal SPECT offers more information (100 per cent). In conclusion, performing both ictal and interictal SPECT studies may provide data about both seizure origin and its relationship with structurally abnormal regions of the brain.     

Ictal SPECT in Nonlesional Extratemporal Epilepsy

Summary:  Purpose: Ictal single-photon emission computed tomography (SPECT) may be a reliable indicator of the ictal onset zone in patients with intractable partial epilepsy who are being considered for epilepsy surgery. The rationale for the illustrated case report is to evaluate the use of an innovation in SPECT imaging in a patient with nonlesional extratemporal epilepsy.
Methods: We investigated the presurgical evaluation and operative outcome in a patient with intractable partial epilepsy. The ictal semiology indicated a "hypermotor" seizure with bipedal automatism. The electroclinical correlation and magnetic resonance imaging (MRI) did not suggest the appropriate localization of the epileptogenic zone. A subtraction periictal SPECT coregistered to MRI (SISCOM) was peformed.
Results: SISCOM revealed a region of localized hyperperfusion in the right supplementary sensorimotor area. Chronic intracranial EEG monitoring confirmed the relationship between the localized SISCOM alteration and the ictal onset zone. The patient was rendered seizure free after surgical treatment.
Conclusions: SISCOM may be used to identify potential candidates for surgical treatment of nonlesional extratemporal epilepsy. Periictal imaging may also alter the strategy for intracranial EEG recordings and focal cortical resection.     

颞叶内侧结构弥散张量成像及白质纤维束成像在颞叶癫痫诊断中的应用价值

目的 通过磁共振弥散张量成像(DTI)及白质纤维束示踪(DTT)技术定量分析颞叶癫痫患者双侧颞叶内侧结构弥散参数值及局部纤维束变化特点,评价DTI技术对颞叶癫痫的诊断价值.方法 对广州医学院第二附属医院自2010年12月至2011年2月临床诊断为颞叶癫痫的16例患者和20例健康志愿者进行常规MRI及DTI扫描,测量双侧颞叶杏仁体、海马及颞叶皮质的部分各向异性(FA)、相对各向异性(RA)、表观弥散系数(ADC)等数值并进行统计学分析,同时应用DTT技术观察癫痫患者局部纤维束与正常对照者的差异.结果 正常对照者双侧颞叶内侧各结构FA、RA、ADC值比较差异均无统计学意义(P＞0.05).颞叶癫痫患侧、对侧与正常对照者颞叶内侧各结构FA、RA、ADC值比较差异均有统计学意义(P＜0.05),其中ADC值呈颞叶癫痫患侧＞颞叶癫痫对侧＞正常对照者的变化趋势,以海马尾部变化最为显著;而FA、RA值呈颞叶癫痫患侧＜颞叶癫痫对侧＜正常对照者的变化趋势,并且杏仁体、海马体部变化较海马尾部更显著.结论 DTI技术能充分了解癫痫患者颞叶内侧结构的弥散参数值及纤维束变化特点,有助于癫痫病灶定位的准确诊断,同时加深对颞叶内侧结构整体变化的了解亦有助于术前的整体评估及提高手术疗效.     

Noninvasive continuous functional near‐infrared spectroscopy combined with electroencephalography recording of frontal lobe seizures

Purpose: To investigate spatial and metabolic changes associated with frontal lobe seizures. Methods: Functional near‐infrared spectroscopy combined with electroencephalography (EEG‐fNIRS) recordings of patients with confirmed nonlesional refractory frontal lobe epilepsy (FLE). Key Findings: Eighteen seizures from nine patients (seven male, mean age 27 years, range 13–46 years) with drug‐refractory FLE were captured during EEG‐fNIRS recordings. All seizures were coupled with significant hemodynamic variations that were greater with electroclinical than with electrical seizures. fNIRS helped in the identification of seizures in three patients with more subtle ictal EEG abnormalities. Hemodynamic changes consisted of local increases in oxygenated (HbO) and total hemoglobin (HbT) but heterogeneous deoxygenated hemoglobin (HbR) behavior. Furthermore, rapid hemodynamic alterations were observed in the homologous contralateral region, even in the absence of obvious propagated epileptic activity. The extent of HbO activation adequately lateralized the epileptogenic side in the majority of patients. Significance: EEG‐fNIRS reveals complex spatial and metabolic changes during focal frontal lobe seizures. Further characterization of these changes could improve seizure detection, localization, and understanding of the impact of focal seizures.