1/229. Surgical management of pediatric tumor-associated epilepsy.Brain tumors are a common cause of seizures in children. Early surgical treatment can improve seizure outcome, but controversy exists regarding the most appropriate type of surgical intervention. Some studies suggest tumor resection alone is sufficient, while others recommend mapping and resection of the surrounding epileptogenic foci to optimize seizure outcome. To address this issue, we reviewed the charts of 34 pediatric patients aged 18 months to 20 years with medically intractable epilepsy and primary brain tumors. The average age at operation was 12.6 years, and patients had seizures for an average of 6.4 years. The majority of tumors were located in the temporal lobe. Seventeen patients, because of tumor location near an eloquent area, underwent extraoperative mapping using subdural electrode grids prior to definitive tumor resection. Fourteen of these patients had a gross total tumor resection, yet only two had a distinct zone of ictal onset identified and resected. The remaining 17 patients had tumors either in the nondominant hemisphere or far removed from speech-sensitive areas, and therefore did not undergo extraoperative subdural electroencephalograph mapping. Fourteen of these patients also had a gross total tumor resection, while none had intraoperative electrocorticography to guide the resection of additional nontumoral tissue. overall, of the 28 patients treated with a gross total tumor resection, 24 (86%) are seizure free, while the other four are significantly improved. Of the six patients who had a subtotal tumor removal, five have persistent seizures. The mean follow-up was 3.6 years. We conclude that in children and adolescents, completeness of tumor resection is the most important factor in determining seizure outcome. The routine mapping and resection of epileptogenic foci might not be necessary in the majority of patients. As a corollary, the use of subdural electrode grids in pediatric patients with tumor-associated epilepsy should be limited to cases requiring extraoperative cortical stimulation for localization of nearby eloquent cortex.- - - - - - - - - - ranking = 1keywords = cortex (Clic here for more details about this article) |
2/229. Integration of preoperative and intraoperative functional brain mapping in a frameless stereotactic environment for lesions near eloquent cortex. Technical note.The authors present a method of incorporating preoperative noninvasive functional brain mapping data into the frameless stereotactic magnetic resonance (MR) imaging dataset used for image-guided resection of brain lesions located near eloquent cortex. They report the use of functional (f)MR imaging and magnetic source (MS) imaging for preoperative mapping of eloquent cortex in difficult cases of brain tumor resection such as those in which there are large expansive masses or in which reoperations are required and the anatomy is distorted from prior treatments. To correlate methods of preoperative and intraoperative mapping localization directly, the authors have developed techniques of importing preoperative MS and fMR imaging data into an image-guided frameless stereotactic computer workstation. The data appear as a seamless overlay on the same preoperative volumetric MR imaging dataset used for stereotactic guidance during the operation. Intraoperatively identified functional locations mapped by cortical stimulation are recorded as digitally registered points. This approach should prove useful in assessing the accuracy and reliability of various preoperative functional brain mapping techniques.- - - - - - - - - - ranking = 6keywords = cortex (Clic here for more details about this article) |
3/229. Minimally invasive stereotactically-guided extirpation of brain stem cavernoma with the aid of electrophysiological methods.The surgical extirpation of brain stem cavernomas always includes a risk of neurological deficits. To minimize the risk of deficits and control the motor and sensory function intraoperative monitoring of SEP and MEP seems to be helpful. The high density of motor and sensory fibers within the brain stem makes bilateral intraoperative monitoring necessary. The following case demonstrates a stereotactically-guided supratentorial, transventricular approach for extirpation of a brain stem cavernoma. Sensory and motoric functions were observed by transcranial recording of SEP's and by transcranial stimulation of motor cortex.- - - - - - - - - - ranking = 1keywords = cortex (Clic here for more details about this article) |
4/229. Surgical treatment of intractable epilepsy originating from the primary sensory area of the hand--case report.A 14-year-old right-handed girl presented with intractable epilepsy originating from the primary sensory area of the hand, manifesting as sensory partial seizures in the left hand with secondary generalization. Neurological examination showed no abnormal findings. magnetic resonance imaging, magnetoencephalography, and cortical stimulation using chronic subdural electrodes demonstrated a lesion located in the primary sensory cortex of the hand, in which the ictal onset zone was identified by 24-hour intracranial electroencephalographic recording. Surgical resection of the lesion and multiple subpial transections of the adjacent cortices were performed. The histological diagnosis was dysembryoplastic neuroepithelial tumor (DNT). She was completely free of seizures without permanent sensory deficits postoperatively. DNT located in the primary sensory hand area may be resectable without causing postoperative sensory deficits, if accurate functional mapping and surgical resection are performed.- - - - - - - - - - ranking = 1keywords = cortex (Clic here for more details about this article) |
5/229. Functional neuronavigation with magnetoencephalography: outcome in 50 patients with lesions around the motor cortex.OBJECT: The authors conducted a study to evaluate the clinical outcome in 50 patients with lesions around the motor cortex who underwent surgery in which functional neuronavigation was performed. methods: The sensorimotor cortex was identified in all patients with the use of magnetoencephalography (MEG). The MEG-source localizations were superimposed onto a three-dimensional magnetic resonance image and the image data set was implemented into a neuronavigation system. Based on this setup, the surgeon chose the best surgical strategy. During surgery, the pre- and postcentral gyri were identified by neuronavigation and, in addition, the central sulcus was localized using intraoperative recording of somatosensory evoked potentials. In all cases MEG localizations of the sensory or motor cortex were correct. In 30% of the patients preoperative paresis improved, in 66% no additional deficits occurred, and in only 4% (two patients) deterioration of neurological function occurred. In one of these patients the deterioration was not related to the procedure. CONCLUSIONS: The method of incorporating functional data into neuronavigation systems is a promising tool that can be used in more radical surgery to lessen morbidity around eloquent brain areas.- - - - - - - - - - ranking = 7keywords = cortex (Clic here for more details about this article) |
6/229. Preoperative PET activation for assessment of motor cortex area in precentral chondroma.BACKGROUND: A main problem in the preoperative planning for precentral tumors is the exact assessment of the spatial relationship between the tumor and the functionally relevant brain areas, which may be difficult using only morphologically oriented imaging (CT, MRI). Therefore, we applied motor activation PET and PET/MRI overlay in a patient with a precentral tumor. DESCRIPTION: We report the case of a 21-year-old woman suffering from progressive right-sided headache and intermittent dysesthesia of the left leg. MRI showed a hypointense tumor with inhomogenous contrast enhancement in the right precentral area. For preoperative assessment of the spatial relationship between the tumor and the motor cortex area, the patient underwent two F-18-fluorodeoxyglucose positron emission tomography (PET) scans (1. resting condition and 2. motor activation of the left leg) and subsequent calculation of subtraction images of activation minus rest. Fusion of PET and MRI data (PET/MRI overlay) was performed for bimodal function and morphology presentation. PET revealed an activation pattern behind and below the tumor, indicating that the motor cortex area was shifted to the back. PET findings were confirmed by intraoperative electrophysiology. Cortical stimulation combined with intraoperative neuronavigation localized the motor area of the left foot and leg exactly at the dorsal border, below and lateral to the lesion. After complete resection of the solid tumor, histopathological examination revealed a chondroma. The postoperative course was uneventful, and the patient was discharged without neurological deficits. CONCLUSIONS: This case shows that biomodal imaging (PET/MRI) provides a noninvasive exact assessment of functionally important cortex areas for preoperative planning in patients with cerebral lesions.- - - - - - - - - - ranking = 7keywords = cortex (Clic here for more details about this article) |
7/229. Intraoperative validation of functional magnetic resonance imaging and cortical reorganization patterns in patients with brain tumors involving the primary motor cortex.OBJECT: The purpose of the present study was to compare the results of functional magnetic resonance (fMR) imaging with those of intraoperative cortical stimulation in patients who harbored tumors close to or involving the primary motor area and to assess the usefulness of fMR imaging in the objective evaluation of motor function as part of the surgical strategy in the treatment of these patients. methods: A total of 11 consecutive patients, whose tumors were close to or involving the central region, underwent presurgical blood oxygen level-dependent fMR imaging while performing a motor paradigm that required them to clench and spread their hands contra- and ipsilateral to the tumor. Statistical cross-correlation functional maps covering the primary and secondary motor cortical areas were generated and overlaid onto high-resolution anatomical MR images. Intraoperative electrical cortical stimulation was performed to validate the presurgical fMR imaging findings. In nine (82%) of 11 patients, the anatomical fMR imaging localization of motor areas could be verified by intraoperative electrical cortical stimulation. In seven patients two or more activation sites were demonstrated on fMR imaging, which were considered a consequence of reorganization phenomena of the motor cortex: contralateral primary motor area (nine patients), contralateral premotor area (four patients), ipsilateral primary motor area (two patients), and ipsilateral premotor area (four patients). CONCLUSIONS: Functional MR imaging can be used to perform objective evaluation of motor function and surgical planning in patients who harbor lesions near or involving the primary motor cortex. Correlation between fMR imaging findings and the results of direct electrical brain stimulation is high, although not 100%. Based on their study, the authors believe that cortical reorganization patterns of motor areas might explain the differences in motor function and the diversity of postoperative motor function among patients with central tumors.- - - - - - - - - - ranking = 6keywords = cortex (Clic here for more details about this article) |
8/229. Intra-operative optical method using intrinsic signals for localization of sensorimotor area in patients with brain tumor.The purpose of this study is intra-operatively to localize the sensorimotor area by intrinsic optical method detecting the changes in regional cerebral blood flow (rCBF) and cortical temperature following neuronal activity during median nerve stimulation. In 18 patients with brain tumors located around the sensorimotor cortex, cortical recording of somatosensory evoked potentials (SEPs) was performed and localized changes in rCBF during median nerve stimulation were measured by a laser-Doppler flowmeter on the locations of SEPs and around the activation area obtained by functional magnetic resonance imaging (fMRI). In two patients, cortical thermomapping was also performed during median nerve stimulation. In fMRI study, the significant activation area of sensorimotor could be obtained in 17 of 18 patients. In cortical recording of SEPs, the polarity reversal of N20 and P20 was observed in 14 of the 18 patients. In 9 of the 14 patients in whom SEPs could be recorded, the localized changes in rCBF, corresponding to the stimulation, were detected in the N20 area. In 2 of the 4 patients in whom N20 could not be recorded successfully, the localized changes in rCBF could be detected. The increase in rCBF during the stimulation was 18.3% /- 5.3% (mean /- SD, n = 11). Thermomapping could demonstrate the localized area, where the increase in rCBF was also detected, by observation of the changes in cortical temperature during the stimulation. The intra-operative intrinsic optical method detecting rCBF and cortical temperature in combination with recording of SEPs may be considered useful for brain functional localization related to neurosurgical disorders.- - - - - - - - - - ranking = 1keywords = cortex (Clic here for more details about this article) |
9/229. Impairment of social and moral behavior related to early damage in human prefrontal cortex.The long-term consequences of early prefrontal cortex lesions occurring before 16 months were investigated in two adults. As is the case when such damage occurs in adulthood, the two early-onset patients had severely impaired social behavior despite normal basic cognitive abilities, and showed insensitivity to future consequences of decisions, defective autonomic responses to punishment contingencies and failure to respond to behavioral interventions. Unlike adult-onset patients, however, the two patients had defective social and moral reasoning, suggesting that the acquisition of complex social conventions and moral rules had been impaired. Thus early-onset prefrontal damage resulted in a syndrome resembling psychopathy.- - - - - - - - - - ranking = 5keywords = cortex (Clic here for more details about this article) |
10/229. Dysembryoplastic neuroepithelial tumor. A case report.Dysembryoplastic neuroepithelial tumor (DNT) is a rare, benign tumor encountered in the cortex. It is characterized by the presence of cells of different histogenesis. Due to its mixed nature (glial-neuronal), WHO histological classification of brain tumors included it into the group of neuronal and glial-neuronal mixed tumors. Case of tumor in a 19-year-old woman experiencing for three years seizure of temporal lobe epilepsy is presented. A cranial magnetic resonance imaging (MRI) showed "pseudocystic" tumor in temporal lobe. Histological and immunocytochemical examinations of the tumor fragment removed during surgery revealed large numbers of neuronalglial nodules occurring in the cerebral cortex. Columns of glial-neuronal structures crossing parallely to the cortex surface, surrounded by oligodendrocyte-like cells (OLC) were a characteristic feature of the tumor texture. In the tumor interstitium, "floating" maturated, dysplastic-free ganglionic cells were visible in numerous bright spaces. In addition, numerous lobuliform--structured areas consisted of oligodendrocyte-like cells. Oligodendrocyte-like cells were characterized by positive immunoreaction to the presence of S-100 protein and synaptophysin. Basing on clinical manifestation and histopathological findings dysembryoplastic neuroepithelial tumor was diagnosed.- - - - - - - - - - ranking = 3keywords = cortex (Clic here for more details about this article) |
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