• Journal of Korean Neurosurgical Society
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• v.29 no.7
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• pp.954-958
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• 2000

In the removal of small subcortical lesion in the eloquent area like sensory-motor cortex, the prevention of neurologic deficit is important. We present our technique of identification of M-1, S-1 cortex in a case of subcortical granuloma located in sensorymotor cortex. To accurately localize mass, stereotactic craniotomy was planned. At the beginning of procedure, functional MRI of motor cortex was done with stereotactic headframe in place. Next, the stereotactic craniotomy about 4 cm was done under propofol anesthesia for cortical mapping. After reflection of dura, central sulcus was identified with phase-reversal response of intraoperative SEP(somatosensory evoked potential) of contralateral median nerve. Then the patient was awakened, and direct cortical stimulation was done. We observed the muscle contractions of elbow, hand and fingers and the paresthesia over forearm, hand, fingers on the M-1 and S-1 cortex. Through cortical mapping and stereotactic guidance, we concluded that the mass lie immediately posterior to central sulcus, then the mass was carefully removed through small transsulcal approach, opening about 1 cm of rolandic sulcus.

• Journal of Korean Neurosurgical Society
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• v.29 no.6
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• pp.815-821
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• 2000

Parasplenial arteriovenous malformations(AVMs) are rare vascular malformations which have distinct clinical and anatomical features. They are situated at the confluence of the hippocampus, isthmus of the cingulate gyrus and the gyrus occipitotemporalis medialis. These lesions are anterior to the calcarine sulcus and their apex extends towards the medial surface of the trigonum. Posterolaterally, these lesions are in close proximity to the visual cortex and optic radiation. The objectives in the surgery of parasplenial AVMs are complete resection of the lesions and preservation of vision. These objectives must be achieved with comprehensive understanding of the following anatomical features :1) the deep central location of the lesions within eloquent brain tissue ; 2) the lack of cortical representation of the AVMs that requires retraction of visual cortex ; 3) deep arterial supply ; 4) deep venous drainage ; 5) juxtaposition to the choroid plexus with which arterial supply and venous drainage are shared. A 16-year-old female student presented with intraventricular hemorrhage from a right parasplenial-subtrigonal AVM. The lesion, fed by posterior cerebral artery and drained into the vein of Galen, was successfully treated by the inter-hemispheric parietooccipital approach. To avoid visual field defect a small incision was made on precuneus anterior to the calcarine sulcus. In this report, the authors describe a surgical approach with special consideration on preservation of visual field.

• 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.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.2
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• pp.123-128
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• 2005

Magnetoencephalography (MEG) is the measurement of the magnetic fields produced by electrical activity in the brain, usually conducted externally, using extremely sensitive devices such as Superconducting Quantum Interference Device (SQUID). MEG needs complex and expensive measurement settings. Because the magnetic signals emitted by the brain are on the order of a few femtoteslas (1 fT = 10-15T), shielding from external magnetic signals, including the Earth's magnetic field, is necessary. An appropriate magnetically shielded room is very expensive, and constitutes the bulk of the expense of an MEG system. MEG is a relatively new technique that promises good spatial resolution and extremely high temporal resolution, thus complementing other brain activity measurement techniques such as electroencephalography (EEG), positron emission tomography (PET), single-photon emission computed tomography (SPECT) and functional magnetic resonance imaging (fMRI). MEG combines functional information from magnetic field recordings with structural information from MRI. The clinical uses of MEG are in detecting and localizing epileptic form spiking activity in patients with epilepsy, and in localizing eloquent cortex for surgical planning in patients with brain tumors. Magnetoencephalography may be used alone or together with electroencephalography, for the measurement of spontaneous or evoked activity, and for research or clinical purposes.

• Clinical and Experimental Pediatrics
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• v.63 no.3
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• pp.88-95
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• 2020

Accurate localization of the seizure onset zone is important for better seizure outcomes and preventing deficits following epilepsy surgery. Recent advances in neuroimaging techniques have increased our understanding of the underlying etiology and improved our ability to noninvasively identify the seizure onset zone. Using epilepsy-specific magnetic resonance imaging (MRI) protocols, structural MRI allows better detection of the seizure onset zone, particularly when it is interpreted by experienced neuroradiologists. Ultra-high-field imaging and postprocessing analysis with automated machine learning algorithms can detect subtle structural abnormalities in MRI-negative patients. Tractography derived from diffusion tensor imaging can delineate white matter connections associated with epilepsy or eloquent function, thus, preventing deficits after epilepsy surgery. Arterial spin-labeling perfusion MRI, simultaneous electroencephalography (EEG)-functional MRI (fMRI), and magnetoencephalography (MEG) are noinvasive imaging modalities that can be used to localize the epileptogenic foci and assist in planning epilepsy surgery with positron emission tomography, ictal single-photon emission computed tomography, and intracranial EEG monitoring. MEG and fMRI can localize and lateralize the area of the cortex that is essential for language, motor, and memory function and identify its relationship with planned surgical resection sites to reduce the risk of neurological impairments. These advanced structural and functional imaging modalities can be combined with postprocessing methods to better understand the epileptic network and obtain valuable clinical information for predicting long-term outcomes in pediatric epilepsy.

• Clinical and Experimental Pediatrics
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• v.56 no.10
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• pp.431-438
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• 2013

Magnetoencephalography (MEG) records the magnetic field generated by electrical activity of cortical neurons. The signal is not distorted or attenuated, and it is contactless recording that can be performed comfortably even for longer than an hour. It has excellent and decent temporal resolution, especially when it is combined with the patient's own brain magnetic resonance imaging (magnetic source imaging). Data of MEG and electroencephalography are not mutually exclusive and it is recorded simultaneously and interpreted together. MEG has been shown to be useful in detecting the irritative zone in both lesional and nonlesional epilepsy surgery. It has provided valuable and additive information regarding the lesion that should be resected in epilepsy surgery. Better outcomes in epilepsy surgery were related to the localization of the irritative zone with MEG. The value of MEG in epilepsy surgery is recruiting more patients to epilepsy surgery and providing critical information for surgical planning. MEG cortical mapping is helpful in younger pediatric patients, especially when the epileptogenic zone is close to the eloquent cortex. MEG is also used in both basic and clinical research of epilepsy other than surgery. MEG is a valuable diagnostic modality for diagnosis and treatment, as well as research in epilepsy.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• v.25 no.3
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• pp.316-321
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• 2023

Developmental venous anomalies (DVAs) are composed of mature venous vessels that lack malformed or neoplastic elements. Although the hemorrhage risk is considered negligible, some patients may have neurological symptoms attributable to acute infarction or intracranial hemorrhage secondary to thrombosis, in the absence of a coexisting cavernous malformation. We report the case of a 42-year-old patient who presented with acute left-hand paresis secondary to a subcortical hemorrhage. This bleeding originated from a DVA in the corticospinal tract area and was surgically drained through an awake craniotomy. To accomplish this, we used a trans-precentral sulcus approach. After the complete removal of the coagulum, small venous channels appeared, which were coagulated. No associated cavernoma was found. Although the main DVA trunk was left patent, no signs of ischemia or venous infarction were observed after coagulating the small venous channels found inside the hematoma cavity. Two weeks after the procedure, the patient's hand function improved, and he was able to resume desktop work. DVA-associated hemorrhage within the cortico-spinal tract could be safely removed with modern awake mapping techniques. This technique allowed the patient to rapidly improve his hand function.

• Journal of Korean Neurosurgical Society
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• v.56 no.3
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• pp.237-242
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• 2014

Objective : The purpose of this study was to investigate the clinical features and outcomes of pediatric cavernous malformation (CM) in the central nervous system. Methods : Twenty-nine pediatric patients with supratentorial CM underwent microsurgical excision. In selected cases, transparent tubular retractor system (TTRS) was used to reduce retraction injury and intraoperative neuromonitoring (IONM) was held to preserve functioning cortex. Patients' demographics and symptoms were reviewed and surgical outcomes were discussed. Results : The main initial clinical manifestations included the following : seizures (n=13, 45%), headache (n=7, 24%), focal neurological deficits (n=3, 10%), and an incidental finding (n=6, 21%). Overt hemorrhage was detected in 7 patients (24%). There were 19 children (66%) with a single CM and 10 (34%) children with multiple CMs. In 7 cases with deep-seated CM, we used a TTRS to minimize retraction. In 9 cases which location of CM was at eloquent area, IONM was taken during surgery. There was no major morbidity or mortality after surgery. In the 29 operated children, the overall long-term results were satisfactory : 25 (86%) patients had no signs or symptoms associated with CMs, 3 had controllable seizures, and 1 had mild weakness. Conclusion : With the assistance of neuronavigation systems, intraoperative neuromonitoring, and TTRS, CMs could be targeted more accurately and excised more safely. Based on the satisfactory seizure outcome achieved, complete microsurgical excision in children is recommended for CMs presenting with seizures but removal of hemosiderin-stained areas seems to be unnecessary.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.3
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• pp.971-977
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• 2015

Malignant glioblastoma multiforme (GBM) is the most malignant brain tumor and despite recent advances in diagnostics and treatment prognosis remains poor. In this retrospective study, we assessed the clinical and radiological parameters, as well as fluorescence in situ hybridization (FISH) of 1p19q deletion, in a series of cases. A total of 816 patients with GBM who received surgery and radiation between January 2010 and May 2014 were included in this study. Kaplan-Meier survival analysis and Cox regression analysis were used to find the factors independently influencing patient progression free survival (PFS) and overall survival (OS). Age at diagnosis, preoperative Karnofsky Performance Scale (KPS) score, KPS score change at 2 weeks after operation, neurological deficit symptoms, tumor resection extent, maximal tumor diameter, involvement of eloquent cortex or deep structure, involvement of brain lobe, Ki-67 and MMP9 expression level and adjuvant chemotherapy were statistically significant factors (p<0.05) for both PFS and OS in the univariate analysis. Cox proportional hazards modeling revealed that age ${\leq}50$ years, preoperative KPS score ${\geq}80$, KPS score change after operation ${\geq}0$, involvement of single frontal lobe, deep structure involvement, low Ki-67 and MMP9 expression and adjuvant chemotherapy were independent favorable factors (p<0.05) for patient clinical outcomes.