Surgical treatment for intractable epilepsy: update and future]

For successful surgical treatment of intractable epilepsy, identification of the epileptogenic area and functional cortex, by using the intracranial electrodes such as subdural and depth electrodes, is important. Since 1994, via chronic subdural electrodes recording, we performed anterior temporal lobectomy with hippocampectomy for 18 patients with temporal lobe epilepsy. For 10 patients with extratemporal lobe epilepsy, cortical resection of the epileptogenic cortex was performed. For the epileptogenic cortex overlapping with functional area, we added the multiple subpial transection. Favorable postoperative seizure outcome was obtained in most of the patients. Although non-invasive presurgical evaluation modalities such as MRI, video-EEG monitoring, MEG, and FDG-PET are useful in the diagnosis of epilepsy, it is impossible to localize precisely the exact epileptogenic zone and functional cortex.     

Comparison of various imaging modalities in localization of epileptogenic lesion using epilepsy surgery outcome in pediatric patients

PurposeWe employed the results of imaging modalities from pediatric patients who received successful epilepsy surgery to determine the accuracy of each imaging tool in identifying epileptic zones in youngsters.MethodsAll Engel class I pediatric patients who received epilepsy surgery between October 2003 and April 2008 were selected. Their pathology, EEG, MRI, PET, and subtraction ictal SPECT coregistered to MRI (SISCOM) results were compared for accuracy in locating the epileptic foci, defined as “area that resulted in seizure ablation after resection”.ResultsForty-two patients were enrolled (23 temporal lobectomy, 19 extratemporal resections). MRI showed concordance in 84.2% of extratemporal cases, all of which had precise localization of lesions. In temporal cases, lateralization was 91.3% and localization was 82.6%. PET showed a concordance rate of 95.5% and localization was 72.7% for temporal lesions. For extratemporal lesions, concordance was only 68.4%. SISCOM showed concordance in 100% of temporal and 92.3% of extratemporal cases, with localization in 66.7% of temporal and 84.6% of extratemporal cases. Most temporal lobe cases had hippocampal sclerosis, and cortical dysplasia was observed in extratemporal cases.DiscussionMRI was invariably reliable in all cases. PET results were as reliable in lateralizing the temporal epileptic area, while its efficacy was lower for extratemporal cases. SISCOM effectively localized lesions in extratemporal cases, but its efficacy was lower in temporal lesions. In cases of conflicting pre-surgical results, MRI, with supplementary data from PET, helped to establish correct decisions in temporal epilepsies, while utilization of SISCOM and MRI data is advised for extratemporal cases.     

Association of ictal aphasia with hypoperfusion in language areas in temporal lobe epilepsy patients

Ictal clinical phenomenology, including aphasia, is usually associated with increased regional cerebral perfusion. We present an unusual pattern of ictal cerebral perfusion in three patients with pharmacoresistant, lesional temporal lobe epilepsy and ictal/postictal aphasia studied with prolonged video-EEG, ictal, and interictal SPECT and MRI for pre-surgical evaluation. Subtraction of ictal-interictal SPECT images co-registered with MRI (SISCOM) showed ictal hyperperfusion in the temporal epileptogenic area in all patients. In addition, hypoperfusion of Broca's area in one case, Wernicke's area in other patient, and both areas in the remaining one were observed. Ictal aphasia in these patients may be explained by functional inhibition of a primary language area, driven by the epileptogenic network. This pattern can contribute to understand the pathophysiology of some ictal signs, with an impact on the evaluation of individual surgical risks.     

Thursday July 6, 2006Thursday July 6, 20067:30–9:00Hall 5ATeaching SessionEpilepsy surgery in infancy and childhood

¹ I. Tuxhorn (   ¹ Epilepsy Center Bethel, Germany )
Epilepsy surgery is no longer a treatment of last resort for children with drug resistant focal epilepsy. It should be considered early to reduce the negative impact of epilepsy on developmental and social outcome.
The spectrum of surgically remediable epilepsy syndromes of childhood has expanded in recent years to include 1) patients with tuberous sclerosis who have a leading resectable focus, 2) infantile spasms or Lennox-Gastaut syndrome (or other age specific epileptic encephalopathies) secondary to a resectable epileptogenic zone and 3) formerly "cryptogenic" cases with very subtle cortical dysplasias.
The goal of the presurgical evaluation is to identify patients who have surgically treatable epilepsy by assessing the risk benefit scenario of surgical intervention.
The accepted standards of evaluation include seizure analysis with video monitoring and scalp recording of the interictal and ictal EEG, high resolution MRI, neuropsychology, WADA test for assessing laterality of mnestic and language functions. Functional imaging including PET, ictal SPECT, postprocessing MRI techniques and fMRI are important techniques to evaluate difficult extratemporal cases.
The role of invasive neurophysiology with subdural, epidural and intracerebral recordings is changing since the advent of functional imaging of the epileptogenic region e.g., EEG triggered MRI and methods outlined above.
Patients with a focal electroclinical syndrome and a congruent MRI lesion are excellent candidates for selection and the seizure outcome prognosis may be considered high if the epileptogenic zone is completely resectable.
In pediatric epilepsy early patient referral for presurgical evaluation should be considered in specific syndromes—catastrophic focal epilepsy, hemispheric syndromes, Sturge Weber syndrome, and well localized symptomatic epilepsies.     

Coregistration of multimodal imaging is associated with favourable two‐year seizure outcome after paediatric epilepsy surgery

Aims. Multimodal coregistration uses multiple image datasets coregistered to an anatomical reference (i.e. MRI), allowing multiple studies to be viewed together. Commonly used in intractable epilepsy evaluation and generally accepted to improve localization of the epileptogenic zone, data showing that coregistration improves outcome is lacking. We compared seizure freedom following epilepsy surgery in paediatric patients, evaluated before and after the use of coregistration protocols at our centre, to determine whether this correlated with a change in outcome. Methods. We included paediatric epilepsy surgery patients with at least one anatomical and one functional neuroimaging study as part of their presurgical evaluation. Preoperatively designated palliative procedures and repeat surgeries were excluded. Multiple pre‐, peri‐, and postoperative variables were compared between groups with the primary outcome of seizure freedom. Results. In total, 115 were included with an average age of 10.63 years (0.12–20.7). All evaluations included video‐EEG (VEEG) and MRI. Seven (6%) had subtraction single‐photon emission CT (SPECT), 46 (40%) had positron emission tomography (PET), and 62 (54%) had both as part of their evaluation. Sixty (52%) had extratemporal epilepsy and 25 (22%) were MRI‐negative. Sixty‐eight (59%) had coregistration. Coregistered patients were less likely to undergo invasive EEG monitoring (p=0.045) and were more likely to have seizure freedom at one (p=0.034) and two years (p<0.001) post‐operatively. A logistic regression accounting for multiple covariates supported an association between the use of coregistration and favourable post‐surgical outcome. Conclusions. Coregistered imaging contributes to favourable postoperative seizure reduction compared to visual analysis of individual modalities. Imaging coregistration is associated with improved outcome, independent of other variables after surgery. Coregistered imaging may reduce the need for invasive EEG monitoring, likely due to improved confidence in presurgical localization. These findings support the use of multimodal coregistered imaging as part of the presurgical assessment in patients evaluated for surgical treatment of intractable epilepsy.     

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.     

Individually tailored extratemporal epilepsy surgery in children: Anatomo-electro-clinical features and outcome predictors in a population of 53 cases

Surgery for refractory extratemporal lobe epilepsy (ETLE) in the pediatric age group has been reported to be associated with a high percentage of failure and relapse. We performed a retrospective study of 53 consecutive patients with epilepsy onset before 12years of age, who underwent, mostly at a pediatric age, an individually tailored ETLE surgery (32 in frontal and 21 in posterior cerebral areas) for pharmacoresistant seizures; these patients were selected and followed by a single national tertiary care pediatric center. Mean age at seizure onset was 3.14years, and mean age at surgery was 11.23years. Complete seizure freedom was achieved in 75% of the subjects. Short duration of illness before surgery, MRI features, no invasive pre-surgical evaluation, a localized interictal and ictal pattern as well as the presence of ictal fast activity on scalp EEG, localized interictal fast rhythms and absence of a diffuse initial ictal modification during SEEG, a complete resection of the epileptogenic zone, a type II FCD, and the absence of acute postoperative seizures correlated in a statistically significant way with a seizure-free outcome. We conclude that the seizure outcome of ETLE surgery in a carefully selected pediatric population can be excellent.     

Preoperative evaluation for temporal lobe surgery.

Temporal lobe epilepsy (TLE), the most common form of partial epilepsy in adults is often refractory to medical treatment and in these patients epilepsy surgery is considered. Successful surgery is dependent on accurate localisation and lateralisation of the epileptogenic zone. The preoperative evaluation involves a series of assessments and investigations including detailed clinical history, interictal EEG, video-EEG monitoring, MRI, PET, SPECT, and neuropsychology and neuropsychiatric assessment. The role of each of these investigations and assessments in the preoperative evaluation is discussed. Advanced MR techniques including magnetic resonance spectroscopy, MR diffusion and MR perfusion have recently been assessed and are likely to enhance the pre-surgical evaluation of patients with TLE.The surgical outcome and preoperative investigations performed of 80 consecutive patients who underwent temporal lobe surgery between 1993 and 2002 at Royal Melbourne Hospital were reviewed. All patients had MRI, video-EEG monitoring and neuropsychology assessment and 56% a PET scan. During a mean follow-up of 5.9 years 75% had Class 1 outcome, 22% non-Class 1 outcome and 3% were lost to follow-up. The results of preoperative investigations were correlated with outcome. For interictal EEG, seizure semiology, ictal EEG, PET and neuropsychology assessment the surgical outcome of patients in whom results were concordant to side of surgery was compared with those discordant or non-lateralising. There was no significant difference. In 78 of 80 patients MRI revealed mesial temporal sclerosis or a foreign tissue lesion. The outcome was no different between these two groups. Results suggest that in patients with unilateral temporal lobe lesion on MRI and where ictal EEG is either concordant or non-lateralising, other investigations including PET, provide little additional prognostic information.     

Intracranial EEG versus flumazenil and glucose PET in children with extratemporal lobe epilepsy

OBJECTIVE: To compare abnormalities determined in 2-deoxy-2-[18F]fluoro-D-glucose (FDG) and [11C]flumazenil (FMZ) PET images with intracranial EEG data in patients with extratemporal lobe epilepsy. BACKGROUND: Although PET studies with FDG and FMZ are being used clinically to localize epileptogenic regions in patients with refractory epilepsy, the electrophysiologic significance of the identified PET abnormalities remains poorly understood. METHODS: We studied 10 patients, mostly children (4 boys, 6 girls, aged 2 to 19 years; mean age, 11 years), who underwent FDG and FMZ PET scans, intracranial EEG monitoring, and cortical resection for intractable epilepsy. EEG electrode positions relative to the brain surface were determined from MRI image volumes. Cortical areas of abnormal glucose metabolism or FMZ binding were determined objectively based on asymmetry measures derived from homotopic cortical areas at three asymmetry thresholds. PET data were then coregistered with the MRI and overlaid on the MRI surface. A receiver operating characteristics (ROC) analysis was performed to determine the specificity and sensitivity of PET-defined abnormalities against the gold standard of intracranial EEG data. RESULTS: FMZ PET detected at least part of the seizure onset zone in all subjects, whereas FDG PET failed to detect the seizure onset region in two of 10 patients. The area under the ROC curves was higher for FMZ than FDG PET for both seizure onset (p = 0.01) and frequent interictal spiking (p = 0.04). Both FMZ and FDG PET showed poor performance for detection of rapid seizure spread (area under the ROC curve not significantly different from 0.5). CONCLUSIONS: [11C]flumazenil (FMZ) PET is significantly more sensitive than 2-deoxy-2-[18F]fluoro-D-glucose (FDG) PET for the detection of cortical regions of seizure onset and frequent spiking in patients with extratemporal lobe epilepsy, whereas both FDG and FMZ PET show low sensitivity in the detection of cortical areas of rapid seizure spread. The application of PET, in particular FMZ PET, in guiding subdural electrode placement in refractory extratemporal lobe epilepsy will enhance coverage of the epileptogenic zone.     

The Relative Contributions of MRI, SPECT, and PET Imaging in Epilepsy

Summary: Functional and structural neuroimaging techniques are increasingly indispensable in the evaluation of epileptic patients for localization of the epileptic area as well as for understanding pathophysiology, propagation, and neurochemical correlates of chronic epilepsy. Although interictal single photon emission computed tomography (SPECT) imaging of cerebral blood flow is only moderately sensitive, ictal SPECT markedly improves yield. Positron emission tomography (PET) imaging of interictal cerebral metabolism is more sensitive than measurement of blood flow in temporal lobe epilepsy. Furthermore, PET has greater spatial resolution and versatility in that multiple tracers can image various aspects of cerebral function. Interpretation of all types of functional imaging studies is difficult and requires knowledge of time of most recent seizure activity and structural correlates. Only magnetic resonance imaging (MRI) can image the structural changes associated with the underlying epileptic process, and quantitative evidence of hippocampal volume loss has been highly correlated with seizure onset in medial temporal structures. Improved resolution and interpretation have made quantitative MRI more sensitive in temporal lobe epilepsy, as judged by pathology. When judged by electroencephalography (EEG), ictal SPECT and interictal PET have the highest sensitivity and specificity for temporal lobe epilepsy; these neuroimaging techniques have lower sensitivity and higher specificity for extratemporal EEG abnormalities. Regardless of the presence of structural abnormalities, functional imaging by PET or SPECT provides complementary information. Ideally these techniques should be used and interpreted together to improve the localization and understanding of epileptic brain.     

Pre-surgical evaluation and surgical treatment in children with extratemporal epilepsy

Introduction This review summarizes some patterns of pre-surgical evaluation and surgical treatment of extratemporal epilepsy in pediatric patients with medically refractory seizures, whose ictal behavior is variable. The most effective treatment for intractable partial epilepsy is a focal cortical resection with excision of the epileptogenic zone (the area of ictal onset and initial seizure propagation). This might be risky, though, in the case of a widespread lesion, sometimes encroaching one or more lobes, given the risk to the functional cerebral cortex. An anterior temporal lobectomy might prove more effective then in preventing seizures with fewer potential complications. If partial extratemporal epilepsy is associated with pharmaco-resistant seizures, the preoperative evaluation and operative strategy are determined according to the epileptogenic zone and to the relationship between a substrate-directed disorder and eloquent areas. The pediatric treatment of extratemporal epilepsy is aimed at controlling the seizures, avoiding morbidity, and improving the patient’s quality of life through psychosocial integration. Since the immature brain is more plastic than when mature, the recovery of functions after surgery is greater in children than in adults.Recommendation Early surgery is recommended for children with intractable epilepsy, and is now accepted as an important therapeutic modality also for children with chronic epilepsy.Conclusion Technological advances in the last two decades, mainly in neuroimaging, have led many medical centers to consider surgical treatment of epilepsy, accuracy being granted by MRI-based neuronavigation systems—an interface between the lesion seen in the preoperative magnetic resonance imaging (MRI) and the operative field, often invisible to the surgeon.     

Functional imaging in the work-up of childhood epilepsy

In children with medically intractable lesional epilepsy, surgery is deemed successful if the epileptogenic focus can be removed while major neurological functions are spared. Current techniques rely on invasive intracranial recordings. The new developments in functional imaging offer the possibility of localizing the epileptogenic focus noninvasively (PET/SPECT) and mapping cognitive functions (fMRI). Ictal SPECT shows hyperperfusion in the focus and has proved to have better localizing value than interictal PET or SPECT, which show focal hypometabolism or hypoperfusion. Ictal SPECT is useful for deciding on the placement of intracranial electrodes in extratemporal epilepsies, particularly in young children. Functional MRI has proved highly accurate for localizing motor and language networks, thus offering the possibilities of replacing the Wada test (language hemispheric lateralization) and studying postlesional brain plasticity. Despite the difficulties of functional imaging in children owing to the limited cooperation that can be expected, ethical constraints, and poor normative data, SPECT/PET and fMRI provide clinically useful information for presurgical work-up of childhood epilepsies. Received: 30 March 2000     

Nichtinvasives Protokoll für die epilepsiechirurgische Behandlung fokaler Epilepsien

We present a non-invasive epilepsy surgery protocol, which includes EEG-video-monitoring, magnetic resonance imaging (MRI), interictal positron emission tomography (PET) and ictal single photon emission computerized tomography (SPECT). According to this non-invasive protocol 50 of 173 patients with medically intractable focal epilepsy underwent resective surgery. The localization of the epileptogenic zone was based on the congruence of the localizing results of EEG-video-monitoring, MRI, interictal PET and ictal SPECT. 46 (92%) of the patients had temporal and 4 (8%) had extratemporal epilepsies. 78% (n = 39) of all patients operated according to our non-invasive protocol were postoperatively completely or almost seizure free. Extramesiotemporal resections could be carried out without invasive EEG-recording if the epileptogenic zone was not adjacent to the eloquent cortex. We conclude from our results that in a considerable number of patients with medically intractable particularly temporal focal epilepsies, resective epilepsy surgery can be based on non-invasive EEG-evaluations and the risk of invasive recordings can be avoided.     

Functional neuroimaging in the preoperative evaluation of children with drug-resistant epilepsy

Functional neuroimaging Although the primary imaging modality in the management of epilepsy is magnetic resonance imaging MRI, functional neuroimaging with positron-emission tomography (PET) and single photon emission computed tomography (SPECT) often provides complementary information and, in a number of situations, provides unique information that cannot be obtained with MRI. The most commonly used PET tracers used for epilepsy evaluation are 2-deoxy-2-[¹⁸F]fluoro-d-glucose (FDG) and [¹¹C]flumazenil (FMZ). Recently, interictal PET with alpha-[¹¹C]methyl-l-tryptophan was found to be highly specific for the epileptic focus and can differentiate between epileptogenic and nonepileptogenic lesions in the same patient (e.g., in patients with tuberous sclerosis).Discussion In this review, we discuss clinical applications of these three PET tracers in drug-resistant temporal and extratemporal lobe epilepsy, selected epilepsy syndromes of childhood, lesional and nonlesional epilepsy, and the challenges of imaging secondary epileptic foci. A brief discussion of SPECT applications in epilepsy is also included. With further development of new tracers highly sensitive and specific for epileptogenic brain regions, the presurgical evaluation of refractory epilepsy will be greatly facilitated. Approximately 0.5 to 1.0% of the population suffer from epilepsy, of which 15–20% are intractable. Infants and children, whose seizures have a focal onset are refractory to anticonvulsants and are prolonged, tend to have the worst cognitive outcome [Meador KJ, Neurology 58 (Suppl 5):S21–S26, 2002]. Seizures themselves affect the developing brain and contribute to an adverse neurologic outcome (Holmes, Pediatric Neurology 33:1–110, 2005).Conclusion Therefore, in treating children with intractable epilepsy, it is important to consider seizure control and to give allowance for normal cognitive development.     

Reduction of benzodiazepine receptor binding is related to the seizure onset zone in extratemporal focal cortical dysplasia

PURPOSE: Comparison of regional reduction of GABA receptor binding and seizure onset zone in patients with extratemporal epilepsy due to focal cortical dysplasia. METHODS: Two patients with frontal lobe epilepsy who remained seizure free after partial frontal lobe resection were investigated with magnetic resonance imaging, positron emission tomography (PET) with 18F-fluoro-deoxy-glucose (FDG) and 11C-flumazenil, subdural EEG-video recordings, and postoperative benzodiazepine (BDZ)-receptor autoradiography. RESULTS: The area of reduced BDZ-receptor binding as documented by preoperative flumazenil-PET and postoperative BDZ-receptor autoradiography corresponded to the seizure onset zone and was smaller than the interictal hypometabolism documented by FDG-PET. CONCLUSION: Flumazenil-PET is a useful tool for localization of the epileptogenic zone in patients with extratemporal epilepsy caused by focal cortical dysplasia. Neuronal distribution of BDZ-receptor density confirms in vivo flumazenil-PET findings. The regional reduction of BDZ-receptor binding in focal cortical dysplasia seems to be confined to the seizure onset zone and not to the extent of dysplastic cortex.     

From the American Epilepsy Society 2009 Annual Course. Non-substrate-directed epilepsy and surgery: PRO and CON

The surgical treatment of epilepsy is the most efficacious therapeutic modality for patients with a medically refractory partial seizure disorder. Epilepsy surgery has been demonstrated to be both effective and well tolerated in individuals with medial temporal lobe epilepsy associated with mesial temporal sclerosis. The identification of an MRI pathological substrate may be useful in identifying the epileptogenic zone and the appropriate operative strategy, and is predictive of the long-term seizure outcome. Patients with a non-substrate-directed partial epilepsy often require a more rigorous presurgical evaluation because of issues regarding the lateralization and localization of the epileptic brain tissue. The surgical outcome may be most disappointing in individuals with localization-related epilepsy of extratemporal origin associated with a normal MRI study. The present discussion focuses on the selection of patients with extratemporal non-substrate-directed epilepsy for a presurgical evaluation. The important factors associated with an improved quality of life subsequent to epilepsy surgery include seizure remission and avoidance of operation-induced adverse effects.     

Pre-surgical evaluation and surgical outcome of 41 patients with non-lesional neocortical epilepsy.

Pre-surgical evaluation and the surgical treatment of non-lesional neocortical epilepsy is one of the most challenging areas in epilepsy surgery. The aim of this study was to evaluate the surgical outcome and the diagnostic role of ictal scalp electroencephalography (EEG), interictal (18)F-fluorodeoxyglucose-positron emission tomography (FDG-PET), and ictal technetium-99m hexamethylpropyleneamine oxime single photon emission tomography ( (99m)Tc-HMPAO SPECT). In 41 non-lesional neocortical epilepsy patients (16 frontal lobe epilepsy, 11 neocortical temporal lobe epilepsy, seven occipital lobe epilepsy, four parietal lobe epilepsy, and three with multifocal onset) who underwent surgical treatment between December 1994 and July 1998, we evaluated the surgical outcome with a follow-up of at least 1 year. The localizing and lateralizing values of ictal scalp EEG, interictal FDG-PET, and ictal SPECT were evaluated in those patients with good surgical outcome. Ictal scalp EEG had the highest diagnostic sensitivity in the localization of epileptogenic foci (69.7% vs. 42.9% for FDG-PET and 33.3% for ictal SPECT; P= 0.027). However, no significant difference was found in the lateralization of the epileptogenic hemisphere among the three modalities (78.8% for ictal scalp EEG, 57.2% for FDG-PET, and 55.5% for ictal SPECT; P= 0.102). During a mean follow-up of 2.77 +/- 1.12 years, 33 (80.5%) showed good surgical outcome (seizure free or seizure reduction >90%), including 16 (39.0%) seizure free patients. Ictal scalp EEG was the most useful diagnostic tool in the localization of epileptogenic foci. Interictal FDG-PET and ictal SPECT were found to be useful as complementary and, sometimes, independent modalities. Many patients with non-lesional neocortical epilepsy would benefit from surgical treatment.     

顽固性癫痫病人术前综合评估在致痫灶定位中的应用

目的　探讨常规脑电图 (REEG)、视频脑电图 (VEEG)、MRI、SPECT检查对癫痫病的诊断及术前综合评估在致痫灶定位中的意义。方法　对 6 8例顽固性癫痫病人行REEG、VEEG、MRI及SPECT检查 ,对 4 4例顽固性癫痫病人术中行皮层电极 (ECoG)和深部电极监测 ,同时对REEG、VEEG、MRI和SPECT用于癫痫病人的诊断和致痫灶的定位价值进行对比研究。结果　 6 8例癫痫患者中REEG局灶棘波检出 30例 (4 1.1% ) ,VEEG局灶棘波检出 5 1例 (75 % ) ,经统计学分析局灶棘波检出率在两者之间有显著性差异 (P <0 .0 1)。SPECT异常 32例(80 % ) ,MRI异常 4 7例 (6 9.1% )。在 4 4例行癫痫手术治疗的病人中 ,ECoG与VEEG定位一致 39例 (88.7% ) ,与MRI异常部位一致 33例 (75 % ) ,1例VEEG异常部位与MRI不一致的病例 ,经ECoG证实致痫灶为VEEG异常部位。结论　VEEG对于癫痫的诊断及致痫灶的定位有相当重要的临床价值 ,优于REEG和MRI。通过临床表现、影像学、功能性检查尤其是VEEG联合检查 ,对顽固性癫痫病人致痫灶的定位具有较大的应用价值     

Neuroimaging of epilepsy

It can sometimes be difficult, when examining surgical specimens, to detect underlying pathological abnormalities that may account for disordered electrical activity. For accurate diagnosis, neuropathologists and clinicians need to share common preoperative information about resected brain tissue. Our group has been able to use structural, functional, and electrophysiological neuroimaging techniques to visualize epileptogenic areas preoperatively. MRI is the most sensitive and useful examination to demonstrate structural abnormalities in patients with partial or localization‐related epilepsy. Temporal lobe epilepsy, neoplastic lesions, vascular lesions, and developmental anomaly can all be surgically corrected under favorable circumstances. Functional neuroimaging by positron emission tomography (PET) and single‐photon emission computed tomography (SPECT) are useful tools for detecting epileptic foci. PET and SPECT demonstrate subtle functional changes related to epilepsy that ultimately may enable the detection of epileptogenic areas invisible to MRI. PET/SPECT images coregistered to MRI and statistical parametric mappings are of more value for detecting than PET/SPECT images alone. Electrophysiological neuroimaging with analytical software is very useful for visually understanding epileptogenic phenomena. Computerized voltage topographic mappings overlapped on three‐dimensional MRI with multichannel electrodes visually demonstrate ictal onset areas and seizure propagation. A new method of multimodal image‐guided intervention enables the detection of epileptogenic areas by electrocorticography, PET images, and MRI during epilepsy surgery. Neuropathologists using this method can collect precise structural, functional, and electrophysiological findings on surgical specimens. Neuroimaging of epilepsy is useful for visually clarifying structural, functional, and electrophysiological information on epilepsy patients. This approach is key for diagnosing the background pathological abnormalities of resected tissue.     

Neuroimaging in epilepsy surgery: a review

In recent years there has been a shift away from invasive monitoring, with more emphasis on the role of neuroimaging, in the selection of patients for epilepsy surgery. Although video-EEG is essential to confirm the diagnosis, and to determine the ictal onset, neuroimaging, in particular magnetic resonance imaging (MRI), forms the basis for selection of most surgical candidates. MRI, using visual analysis, is able to detect hippocampal sclerosis, the most common cause of temporal lobe epilepsy, in the majority of patients with this condition, with quantitative MRI increasing the sensitivity of this imaging technique. Other lesions readily detected on MRI include dysplasia, neuronal migration disorders and cavernomas. Studies have shown that the best postoperative results are achieved in patients with a lesion visible on MRI. Functional imaging, both single photon emission computed tomography (SPECT), in particular ictal SPECT, and photon emission tomography (PET), are important ancillary investigations providing valuable corroborative evidence of a seizure focus.