Objectives:To evaluate the diagnostic value of individual noninvasive presurgical modalities and to study their role in surgical management of nonlesional pediatric epilepsy patients. Methods:We retrospectively studied 14 children (3-18 years) Concordance of localization between each test and iEEG was scored as follows: 2 ϭ lobar concordance; 1 ϭ hemispheric concordance; 0 ϭ discordance or nonlocalization. Total concordance score in each patient was measured by the summation of concordance scores for all 3 tests.Results: Seven (50%) of 14 patients were seizure-free for at least 12 months after surgery. One (7%) had only rare seizures and 6 (43%) had persistent seizures. MEG (79%, 11/14) and SISCOM (79%, 11/14) showed greater lobar concordance with iEEG than SPM-PET (13%, 3/14) (p Ͻ 0.05). SPM-PET provided hemispheric lateralization (71%, 10/14) more often than lobar localization. Total concordance score tended to be greater for seizure-free patients (4.7) than for non-seizure-free patients (3.9). Children with medically intractable epilepsy have been considered for epilepsy surgery if the epileptogenic zone is reasonably localized with noninvasive presurgical evaluation. Conclusions:1-3 Among available noninvasive tests, the most accurate and reliable tool for identification of seizure focus remains MRI. Presence of visible MRI lesion not only warrants surgical candidacy, but also predicts a favorable surgical outcome.4-7 Recent advances with high-resolution MRI may reveal the presence of brain lesions not previously detected. However, some patients continue to have no detectable lesions on MRI, despite the suggestion of a focal epileptogenic zone on seizure semiology and scalp EEG.When no lesion is seen on MRI, other noninvasive functional imaging modalities have been employed: peri-ictal SPECT and subsequent subtraction image coregistered to MRI (SISCOM) may visualize increased blood flow at the time of seizure 8,9 ; 2-deoxy-2-( 18 F)fluoro-D-glucose PET (FDG-PET) and subsequent voxel-based analysis using statistical parametric mapping (SPM) may visualize the areas of decreased metabolism 10 ; and magnetoencephalography (MEG)/magnetic source localization (MSI) may reveal the source of interictal/ictal epileptic discharges.

Summary Purpose Intracranial electroencephalography (EEG) is performed as part of an epilepsy surgery evaluation when noninvasive tests are incongruent or the putative seizure-onset zone is near eloquent cortex. Determining the seizure-onset zone using intracranial EEG has been conventionally based on identification of specific ictal patterns with visual inspection. High-frequency oscillations (HFOs, >80 Hz) have been recognized recently as highly correlated with the epileptogenic zone. However, HFOs can be difficult to detect because of their low amplitude. Therefore, the prevalence of ictal HFOs and their role in localization of epileptogenic zone on intracranial EEG are unknown. Methods We identified 48 patients who underwent surgical treatment after the surgical evaluation with intracranial EEG, and 44 patients met criteria for this retrospective study. Results were not used in surgical decision making. Intracranial EEG recordings were collected with a sampling rate of 2,000 Hz. Recordings were first inspected visually to determine ictal onset and then analyzed further with time-frequency analysis. Forty-one (93%) of 44 patients had ictal HFOs determined with time-frequency analysis of intracranial EEG. Key Findings Twenty-two (54%) of the 41 patients with ictal HFOs had complete resection of HFO regions, regardless of frequency bands. Complete resection of HFOs (n = 22) resulted in a seizure-free outcome in 18 (82%) of 22 patients, significantly higher than the seizure-free outcome with incomplete HFO resection (4/19, 21%). Significance Our study shows that ictal HFOs are commonly found with intracranial EEG in our population largely of children with cortical dysplasia, and have localizing value. The use of ictal HFOs may add more promising information compared to interictal HFOs because of the evidence of ictal propagation and followed by clinical aspect of seizures. Complete resection of HFOs is a favorable prognostic indicator for surgical outcome.

Background. Irradiation, either alone or in association with other factors, is thought to play a role in the causation of intracranial meningioma. Methods. The authors report two 15‐year‐old patients with convexity meningiomas as a result of high‐dose irradiation received at a young age and review the English language literature reports of 13 pediatric patients with meningiomas after high‐dose irradiation. The clinical characteristics of the 15 patients are presented. Results. There were nine girls and six boys. The mean age at the time of irradiation was 2.5 years (2 months‐9 years), and the mean age at diagnosis of meningioma was 13 years (5–15.5 years). The mean radiation dose was 4154 cGy (1500–8000 cGy). In 11 of the 15 patients, the meningioma was located in the calvarial area. Only 1 of 15 had multiple tumors, and only two of the tumors were clearly malignant at diagnosis. In ten patients, gross total resection was recorded, and two patients underwent subtotal resection. Three died of recurrent/disseminated meningiomas. Conclusions. This study suggests that meningiomas after high‐dose radiation in children are mostly calvarial in location, rarely multiple, mostly benign in histologic type, and that complete removal is possible in most patients. The age at the time of radiation is young (mean age, 2.5 years) and the latent period is short (mean, 10.8 years). Although the clinical course of radiation‐induced meningiomas in childhood generally is benign, high doses of radiation at a young age are to be avoided, and other means of therapy should be used if possible.

Summary:  Purpose: The ketogenic diet (KD) has been considered a highly potent antiepileptic treatment for intractable childhood epilepsy. In this study, we compared the antiepileptic efficacy and diet tolerability of two different diets with lipid:nonlipid ratios of 3:1 and 4:1. Methods: Seventy‐six patients with refractory childhood epilepsy were randomly placed into two groups and were started on KD diets with nonlipid:lipid ratios of either 3:1 or 4:1. Antiepileptic efficacy and diet tolerability were evaluated 3 months after initiating the diet. Patients showing seizure‐free outcome with the 4:1 diet were changed to the 3:1 diet, and those without a seizure‐free outcome on the 3:1 diet were changed to the 4:1 diet, for three more months, after which time their progress was monitored. Results: (1) Antiepileptic efficacy was higher for the 4:1 than the 3:1 diet (p < 0.05). Twenty‐two (55.0%) of 40 patients on the 4:1 diet and 11 (30.5%) of 36 patients on the 3:1 diet became seizure free. Seizure reduction of over 90% was observed in 2 (5.0%) patients on the 4:1 diet, and 2 (5.6%) on the 3:1 diet. (2) Dietary tolerability was better for the 3:1 than the 4:1 diet. Gastrointestinal symptoms were observed in 5 (13.9%) patients with the 3:1 diet and 14 (35.0%) patients with the 4:1 diet (p < 0.05). (3) For seizure‐free patients who started on the 4:1 diet, antiepileptic efficacy was maintained after changing to the 3:1 diet, while 10 (83.3%) of 12 patients who were not seizure free with the 3:1 diet showed increased seizure reduction after changing to the 4:1 diet. (4) Complications from the KD and laboratory data were not significantly different between the two groups. Conclusions: The 4:1 KD showed greater antiepileptic efficacy than the 3:1 diet with higher seizure‐free outcome. In most cases, seizure free outcome was maintained even after changing the ratio to 3:1. Dietary tolerability was better in the 3:1 diet than the 4:1 with less frequent gastrointestinal symptoms.