• Nuclear Medicine and Molecular Imaging
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• v.41 no.2
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• pp.97-101
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• 2007

Correct localization of epileptogenic zone is important for the successful epilepsy surgery. Both ictal perfusion single photon emission computed tomography (SPECT) and interictal F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) can provide useful information in the presurgical localization of intractable partial epilepsy. These imaging modalities have excellent diagnostic sensitivity in medial temporal lobe epilepsy and provide good presurgical information in neocortical epilepsy. Also provide functional information about cellular functions to better understand the neurobiology of epilepsy and to better define the ictal onset zone, symptomatogenic zone, propagation pathways, functional deficit zone and surround inhibition zones. Multimodality imaging and developments in analysis methods of ictal perfusion SPECT and new PET ligand other than FDG help to better define the localization.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.172-176
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• 2008

FDG PET has been used as a diagnostic tool for localization of seizure focus for last 2-3 decades. In this article, the clinical usefulness of FDG PET in the management of patients with epilepsy has been reviewed, which provided the evidences to justify the medicare reimbursement for FDG PET in management of patients with epilepsy. Literature review demonstrated that FDG PET provides an important information in localization of seizure focus and determination whether a patients is a surgical candidate or not. FDG PET has been reported to have high diagnostic performance in localization of seizure focus in neocortical epilepsy as well as temporal lobe epilepsy regardless of the presence of structural lesion on MRI. Particularly, FDG PET can provide the additional information when the results from standard diagnositic modality such as interictal or video-monitored EEG, and MRI are inconclusive or discordant, and make to avoid invasive study. Furthermore, the presence of hypometabolism and extent of metabolic extent has been reported as an important predictor for seizure free outcome. However, studies suggested that more accurate localization and better surgical outcome could be expected with multimodal approach by combination of EEG, MRI, and functional studies using FDG PET or perfusion SPECT rather than using a single diagnostic modality in management of patients with epilepsy. Complementary use of FDG PET in management of epilepsy is worth for good surgical outcome in epilepsy patients.

• Clinical and Experimental Pediatrics
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• v.53 no.8
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• pp.779-785
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• 2010

In pre-surgical evaluation of pediatric epilepsy, the combined use of multiple imaging modalities for precise localization of the epileptogenic focus is a worthwhile endeavor. Advanced neuroimaging by high field Magnetic resonance imaging (MRI), diffusion tensor images, and MR spectroscopy have the potential to identify subtle lesions. $^{18}F$-FDG positron emission tomography and single photon emission tomography provide visualization of metabolic alterations of the brain in the ictal and interictal states. These techniques may have localizing value for patients which exhibit normal MRI scans. Functional MRI is helpful for non-invasively identifying areas of eloquent cortex. These advances are improving our ability to noninvasively detect epileptogenic foci which have gone undetected in the past and whose accurate localization is crucial for a favorable outcome following surgical resection.

• Annals of Clinical Neurophysiology
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• v.1 no.2
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• pp.154-159
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• 1999

Magnetoencephalography (MEG), the measurement of magnetic fields produced by neuronal current associated with normal and pathologic brain activities, is a totally noninvasive method for localizing functional regions of the brain. During the past several years, many clinical research centers are working to expand various fundamental functional brain regions, which can be easily localized, as well as to characterize magnetic abnormalities which accompany a wide variety of cerebral disease. At present, MEG is used in a number of clinical centers throughout the world for the presurgical functional localization of eloquent cortex, and for the non-invasive localization of epileptiform activity. And also, non-invasiveness means that it can be used for screening and repetitive follow-up measurement without concern for adverse effects. As procedures for activating various functional brain regions are standardized, and as the effects of specific cerebral diseases on the MEG are carefully documented in controlled studies, the number of routine neurological applications for MEG will increase significantly. In this paper, the basic principles of MEG are reviewed briefly with its clinical application to neurologic disease.

• Journal of Korean Neurosurgical Society
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• v.45 no.4
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• pp.219-223
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• 2009

Objective : Functional magnetic resonance imaging (fMRI) is frequently used to localize language areas in a non-invasive manner. Various paradigms for presurgical localization of language areas have been developed, but a systematic quantitative evaluation of the efficiency of those paradigms has not been performed. In the present study, the authors analyzed different language paradigms to see which paradigm is most efficient in localizing frontal language areas. Methods : Five men and five women with no neurological deficits participated (mean age, 24 years) in this study. All volunteers were right-handed. Each subject performed 4 tasks, including fixation (Fix), sentence reading (SRI. pseudoword reading (PR), and word generation (WG). Fixation and pseudoword reading were used as contrasts. The functional area was defined as the area(s) with a t-value of more than 3.92 in fMRI with different tasks. To apply an anatomical constraint, we used a brain atlas mapping system, which is available in AFNI, to define the anatomical frontal language area. The numbers of voxels in overlapped area between anatomical and functional area were individually counted in the frontal expressive language area. Results : Of the various combinations, the word generation task was most effective in delineating the frontal expressive language area when fixation was used as a contrast (p<0.05). The sensitivity of this test for localizing Broca's area was 81 % and specificity was 70%. Conclusion : Word generation versus fixation could effectively and reliably delineate the frontal language area. A customized effective paradigm should be analyzed in order to evaluate various language functions.

• The Korean Journal of Nuclear Medicine
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• v.26 no.2
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• pp.244-250
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• 1992

Both interictal and ictal $^{99m}Tc-HMPAO$ brain SPECT were performed in 22 patients with medically intractable epilepsy. Localization of epileptic foci in our patients was made by combined results of EEG and other tests, including Wada test, magnetic resonance imaging, and neuropsychometric test. Among them, ictal $^{99m}Tc-HMPAO$ SPECT, localized epilptic foci in 20 of 22 patients and provided evidence of epileptic focus in 12 patients by demonstrating maximally increased regional cerebral perfusion (rCP) in epileptic foci during the ictal study with decreased rCP in interictal study. Ictal $^{99m}Tc-HMPAO$ SPECT was particularly useful for investigating epileptic foci, and when correlated with simultaneously recorded ictal EEG, provided further insight for localizing epileptic foci. Conclusively, $^{99m}Tc-HMPAO$ SPECT is. a useful, noninvasive method of localizing epileptic activity which may be particularly important for presurgical investigations, especially in those patients without large morphological lesions.

• Korean Journal of Radiology
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• v.20 no.1
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• pp.171-179
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• 2019

Objective: For localization of the motor cortex, seed-based resting-state functional MRI (rsfMRI) uses the contralateral motor cortex as a seed. However, research has shown that the location of the motor cortex could differ according to anatomical variations. The purpose of this study was to compare the results of rsfMRI using two seeds: a template seed (the anatomically expected location of the contralateral motor cortex) and a functional seed (the actual location of the contralateral motor cortex determined by task-based functional MRI [tbfMRI]). Materials and Methods: Eight patients (4 with glioma, 3 with meningioma, and 1 with arteriovenous malformation) and 9 healthy volunteers participated. For the patients, tbfMRI was performed unilaterally to activate the healthy contralateral motor cortex. The affected ipsilateral motor cortices were mapped with rsfMRI using seed-based and independent component analysis (ICA). In the healthy volunteer group, both motor cortices were mapped with both-hands tbfMRI and rsfMRI. We compared the results between template and functional seeds, and between the seed-based analysis and ICA with visual and quantitative analysis. Results: For the visual analysis, the functional seed showed significantly higher scores compared to the template seed in both the patients (p = 0.002) and healthy volunteers (p < 0.001). Although no significant difference was observed between the functional seed and ICA, the ICA results showed significantly higher scores than the template seed in both the patients (p = 0.01) and healthy volunteers (p = 0.005). In the quantitative analysis, the functional seed exhibited greater similarity to tbfMRI than the template seed and ICA. Conclusion: Using the contralateral motor cortex determined by tbfMRI as a seed could enhance visual delineation of the motor cortex in seed-based rsfMRI.