Seo JH, Holland K, Rose D, et al. Multimodality imaging in the surgical treatment of children with non-lesional epilepsy. Neurology. 76: 41-48

Division of Pediatric Neurology, Department of Radiology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, 3333 Burnet Avenue, Cincinnati, OH 45229-3339, USA.
Neurology (Impact Factor: 8.29). 01/2011; 76(1):41-8. DOI: 10.1212/WNL.0b013e318204a380
Source: PubMed


To evaluate the diagnostic value of individual noninvasive presurgical modalities and to study their role in surgical management of nonlesional pediatric epilepsy patients.
We retrospectively studied 14 children (3-18 years) with nonlesional intractable focal epilepsy. Clinical characteristics, surgical outcome, localizing features on 3 presurgical diagnostic tests (subtraction peri-ictal SPECT coregistered to MRI [SISCOM], statistical parametric mapping [SPM] analysis of [18F] FDG-PET, magnetoencephalography [MEG]), and intracranial EEG (iEEG) were reviewed. The localization of each individual test was determined for lobar location by visual inspection. Concordance of localization between each test and iEEG was scored as follows: 2=lobar concordance; 1=hemispheric concordance; 0=discordance or nonlocalization. Total concordance score in each patient was measured by the summation of concordance scores for all 3 tests.
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<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).
Our data suggest that MEG and SISCOM are better tools for lobar localization than SPM analysis of FDG-PET in children with nonlesional epilepsy. A multimodality approach may improve surgical outcome as well as selection of surgical candidates in patients without MRI abnormalities.

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Available from: Francesco Mangano, Jan 14, 2014
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    • "FDG-PET plays an important role in noninvasive evaluation of adult patients with intractable partial epilepsy to localize the epiletogenic zone for possible surgical treatment [20] [21]. The evaluative role of FDG-PET would also apply to a pediatric population [22] [23]. It has been shown that cerebral glucose hypometabolism is also a common pathology of CEE and that its treatment may result in improved glucose metabolism when assessed with FDG-PET accompanied by reduced number of epilepsy episodes [24]. "
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    ABSTRACT: Childhood epileptic encephalopathies (CEE) are often characterized by abnormal brain development in which epileptic electrical discharges may contribute to cognitive deficits, behavioral disturbances, or psychomotor dysfunction. Electroencephalography (EEG) is the primary diagnostic imaging tool used by care providers in order to observe the aggressive paroxysmal activity that manifests from CEE. Though EEG is an effective diagnostic tool, it provides limited insight into the etiology and pathophysiology that can be obtained through other imaging techniques. The aim of this paper is to review current neuroimaging techniques, such as intracranial EEG, magnetoencephalography, functional magnetic resonance imaging, and positron emission tomography and discuss how they complement EEG findings and contribute to our understanding of CEE. In addition, we address the value of imaging techniques in defining and predicting cognitive changes in CEE.
    Full-text · Article · Jan 2014
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    • "The wide range of sensitivity estimates is partly due to the different methodological approaches used to determine the spatial extent of spike sources. Most studies used spatial clustering of spikes modeled with single dipole models as an estimate of the volumetric extent of spiking volumes (26, 68–70). However, the extent of spikes’ cluster remains difficult to interpret since it depends on multiple factors including: (1) the spatio-temporal heterogeneity of spike’s MEG signal; (2) their signal- to-noise ratio; and (3) the statistical stability of the solution (71). "
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    ABSTRACT: Despite major advances in neuroimaging, no lesion is visualized on MRI in up to a quarter of patients with drug-resistant focal epilepsy presenting for presurgical evaluation. These patients demonstrate poorer surgical outcomes than those with lesion seen on MRI. Accurate localization of the seizure onset zone (SOZ) is more difficult in MRI-negative patients and often requires invasive EEG recordings. Positron emission tomography (PET) and magnetoencephalography (MEG) have been proposed as clinically relevant tools to localize the SOZ prior to intracranial EEG recordings. However, there is no consensus regarding the optimal gold standard that should be used for assessing the performance of these presurgical investigations. Here, we review the current knowledge concerning the usefulness of PET and MEG for presurgical assessment of MRI-negative epilepsy. Beyond the individual diagnostic performance of MEG and of different PET tracers, including [(18)F]-fluorodeoxyglucose, [(11)C]flumazenil, and markers of 5-HT1A receptors, recent data suggest that the combination of PET and MEG might provide greater sensitivity and specificity than that of each of the two individual tests in patients with normal MRI.
    Full-text · Article · Nov 2013 · Frontiers in Neurology
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    • "Findings are usually analyzed visually, and this is considered to carry powerful detecting value, although it is highly variable according to the location (temporal/extratemporal) and type (positive/negative MRI) of epilepsy [9-11]. PET/MRI coregistration also impacts visual detection [12-14]. SPM proved to be a useful strategy for FDG-PET in adults with refractory focal epilepsy not only in temporal lobe cases [5,7,15-19], but also in extratemporal epilepsy and/or negative MRI, where sensitivity of visual analysis is lower [20]. "
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    ABSTRACT: Background Statistical parametric mapping (SPM) procedure is an objective tool to analyze 18F-fluoro-2-deoxy-d-glucose-positron-emission tomography (FDG-PET) images and a useful complement to visual analysis. However, SPM requires a comparison to control data set that cannot be obtained in healthy children for ethical reasons. Using adults as controls showed some limitations. The purpose of the present study was to generate and validate a group of pseudo-normal children as a control group for FDG-PET studies in pediatrics. Methods FDG-PET images of 47 children (mean ± SD age 10.2 ± 3.1 years) with refractory symptomatic (MRI-positive, n = 20) and cryptogenic (MRI-negative, n = 27) focal epilepsy planned for surgery were analyzed using visual and SPM analysis. Performances of SPM analysis were compared using two different control groups: (1) an adult control group consisting of healthy young adults (n = 25, 30.5 ± 5.8 years, adult PET template) and (2) a pediatric pseudo-control group consisting of patients (n = 24, 10.6 ± 3.1 years, children PET template) with refractory focal epilepsy but with negative MRI and with PET considered normal not only on visual analysis but also on SPM. Results Among the 47 children, visual analysis succeeded detecting at least one hypometabolic area in 87% of the cases (interobserver kappa = 0.81). Regarding SPM analysis, the best compromise between sensitivity and specificity was obtained with a threshold of p less than 0.001 as an extent of more than 40 voxels. There was a significant concordance to detect hypometabolic areas between both SPM analyses [kappa (K) = 0.59; p < 0.005] and between both SPM and visual analyses (K = 0.45; p < 0.005), in symptomatic (K = 0.74; p < 0.005) as in cryptogenic patients (K = 0.26; p < 0.01). The pediatric pseudo-control group dramatically improved specificity (97% vs. 89%; p < 0.0001) by increasing the positive predictive value (86% vs. 65%). Sensitivity remained acceptable although it was not better (79% vs. 87%, p = 0.039). The main impact was to reduce by 41% the number of hypometabolic cortical artifacts detected by SPM, especially in the younger epileptic patients, which is a key point in clinical practice. Conclusions This age-matched pseudo-control group is a way to optimize SPM analysis of FDG-PET in children with epilepsy. It might also be considered for other brain pathologies in pediatrics in the future.
    Full-text · Article · Jan 2013 · EJNMMI Research
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