Combined Utility of Functional MRI, Cortical Mapping, and Frameless Stereotaxy in the Resection of Lesions in Eloquent Areas of Brain in Children

1997 ◽  
Vol 26 (2) ◽  
pp. 68-82 ◽  
Author(s):  
Simon R. Stapleton ◽  
Elaine Kiriakopoulos ◽  
David Mikulis ◽  
James M. Drake ◽  
Harold J. Hoffman ◽  
...  
Keyword(s):  
Functional Mri ◽  
Cortical Mapping ◽  
Frameless Stereotaxy ◽  
Eloquent Areas

Transcranial brain stimulation and structural MRI

2021 ◽  
Author(s):  
Raffaele Dubbioso ◽  
Axel Thielscher
Keyword(s):  
Brain Stimulation ◽  
Structural Mri ◽  
Cortical Mapping ◽  
Functional Markers ◽  
Frameless Stereotaxy ◽  
Brain Scans ◽  
Interindividual Variations ◽  
Age Related ◽  
Transcranial Brain Stimulation ◽  
The Individual

Non-invasive transcranial brain stimulation (NTBS) benefits in multiple ways from structural magnetic resonance imaging (sMRI). Individual structural brain scans can be used to guide spatial targeting with frameless stereotaxy. For instance, sMRI informed transcranial magnetic stimulation (TMS) enables personalized cortical mapping aligned to the individual gyral anatomy. Segmented sMRI scans increase the accuracy and robustness of computational dosimetry approaches which are key to standardize the individual dose across individuals, mapping the NTBS induced electrical fields onto the individual brain. Several sMRI modalities can be used to identify macro and microstructural features that are related to the physiological and behavioral effects of NTBS. Structural MRI before NTBS can identify interindividual variations in brain structure that influence NTBS outcomes, including disease or age related anatomical changes. Repeated structural MRI measurements can trace NTBS induced changes in regional macro and microstructure. NTBS based functional markers can be combined with MRI based structural markers to predict disease progression or recovery in individual patients.

Intraoperative seizures occurrence in cortical mapping of eloquent areas

2021 ◽  
Vol 23 (2) ◽  
pp. 39-44
Author(s):  
Olga A. Toporkova ◽  
Mikhail V. Aleksandrov ◽  
Malik M. Tastanbekov
Keyword(s):  
Cerebral Cortex ◽  
General Anesthesia ◽  
Cortical Mapping ◽  
Motor Mapping ◽  
Eloquent Areas ◽  
Auditory Speech ◽  
Neurophysiological Studies ◽  
Eloquent Cortex ◽  
Structural Epilepsy ◽  
Convulsive Seizures

The effect of structural epilepsy on the frequency of intraoperative convulsive seizures is assessed when mapping functionally significant areas of the cerebral cortex during resection of intracerebral neoplasms. The work is based on the analysis of the results of intraoperative neurophysiological studies at the Polenov Neurosurgical Institute. For the period 20192020 87 intraoperative mappings of eloquent cortex were carried out during resections of intracerebral neoplasms: 79 mappings of the motor cortex and 16 mappings of auditory-speech areas during operations with awakening. When mapping the motor zones of the cortex, the frequency of seizures was 5.1%, while mapping the auditory-speech zones with awakening 18.75%. The division of cases of intraoperative convulsive seizures into two groups: seizures arising from motor mapping and seizures associated with the mapping of auditory zones reflects differences in factors that affect the excitability of the cerebral cortex. In motor mapping, stimulation occurs against the background of general anesthesia, unlike waking operations. The intensity of stimulation in auditory mapping is higher than in motor mapping in motor mapping. Formally, the current used in motor mapping is significantly higher than in mapping auditory zones. In general, with the development of intraoperative convulsive seizures, the current intensity of cortical stimulation does not exceed the average values required to stimulate functionally significant cortical zones. The presence of epileptic syndrome in patients with intracerebral tumors cannot be considered as a predictor of intraoperative seizure development when performing motor mapping under general anesthesia as well as during surgery with awakening for mapping of motor or auditory verbal zones.

AWAKE CRANIOTOMY FOR BRAIN TUMORS NEAR ELOQUENT CORTEX

Neurosurgery ◽  
2009 ◽  
Vol 64 (5) ◽  
pp. 836-846 ◽  
Author(s):  
Stefan S. Kim ◽  
Ian E. McCutcheon ◽  
Dima Suki ◽  
Jeffrey S. Weinberg ◽  
Raymond Sawaya ◽  
...  
Keyword(s):  
Surgical Resection ◽  
Neurological Status ◽  
Extent Of Resection ◽  
Sensory Function ◽  
Neurological Deficits ◽  
Cortical Mapping ◽  
Eloquent Areas ◽  
Eloquent Cortex ◽  
Low Incidence ◽  
Intraoperative Localization

Abstract OBJECTIVE Intraoperative localization of cortical areas for motor and language function has been advocated to minimize postoperative neurological deficits. We report herein the results of a retrospective study of cortical mapping and subsequent clinical outcomes in a large series of patients. METHODS Patients with intracerebral tumors near and/or within eloquent cortices (n = 309) were clinically evaluated before surgery, immediately after, and 1 month and 3 months after surgery. Craniotomy was tailored to encompass tumor plus adjacent areas presumed to contain eloquent cortex. Intraoperative cortical stimulation for language, motor, and/or sensory function was performed in all patients to safely maximize surgical resection. RESULTS A gross total resection (≥95%) was obtained in 64%, and a resection of 85% or more was obtained in 77% of the procedures. Eloquent areas were identified in 65% of cases, and in that group, worsened neurological deficits were observed in 21% of patients, whereas only 9% with negative mapping sustained such deficits (P < 0.01). Intraoperative neurological deficits occurred in 64 patients (21%); of these, 25 (39%) experienced worsened neurological outcome at 1 month, whereas only 27 of 245 patients (11%) without intraoperative changes had such outcomes (P < 0.001). At 1 month, 83% overall showed improved or stable neurological status, whereas 17% had new or worse deficits; however, at 3 months, 7% of patients had a persistent neurological deficit. Extent of resection less than 95% also predicted worsening of neurological status (P < 0.025). CONCLUSION Negative mapping of eloquent areas provides a safe margin for surgical resection with a low incidence of neurological deficits. However, identification of eloquent areas not only failed to eliminate but rather increased the risk of postoperative deficits, likely indicating close proximity of functional cortex to tumor.

The 3-Dimensional Grid

2015 ◽  
Vol 11 (1) ◽  
pp. 127-134 ◽  
Author(s):  
Charles Munyon ◽  
Jennifer Sweet ◽  
Hans Luders ◽  
Samden Lhatoo ◽  
Jonathan Miller
Keyword(s):  
Intractable Epilepsy ◽  
Infectious Complications ◽  
Electrode Placement ◽  
Frameless Stereotaxy ◽  
Seizure Onset ◽  
3 Dimensional ◽  
Eloquent Areas ◽  
Depth Electrodes ◽  
Rectangular Pattern ◽  
Permanent Neurological Deficit

Abstract BACKGROUND Successful surgical treatment of epilepsy requires accurate definition of areas of ictal onset and eloquent brain. Although invasive monitoring can help, subdural grids cannot sample sulci or subcortical tissue; traditional stereoelectroencephalography depth electrodes are usually placed too far apart to provide sufficient resolution for mapping. OBJECTIVE To report a strategy of depth electrode placement in a dense array to allow precise anatomic localization of epileptic and eloquent cortex. METHODS Twenty patients with medically intractable epilepsy either poorly localized or found to arise adjacent to eloquent areas underwent placement of arrays of depth electrodes into and around the putative area of seizure onset with the use of framed stereotaxy. Each array consisted of a “grid” of parallel electrodes in a rectangular pattern with 1 cm between entry sites. In a subset of patients, a few electrodes were placed initially, with additional electrodes placed in a second stage. Trajectories were modified to avoid cortical vessels defined on magnetic resonance imaging. Patients were monitored for 4 to 21 days to establish the precise location of seizure onset. Stimulation was performed to map cortical and subcortical eloquent regions. Electrode locations were coregistered for frameless stereotaxy during subsequent resection of seizure focus. RESULTS Two hundred fifty-four electrodes were implanted. Discrete regions of seizure onset and functional cortex were identified, which were used during resection to remove epileptogenic tissue while preserving eloquent areas. There were no hemorrhagic or infectious complications; no patient suffered permanent neurological deficit. CONCLUSION The 3-dimensional intraparenchymal grid is useful for identifying the location and extent of epileptic and eloquent brain.

scholarly journals Awake Craniotomy for Left Insular Low-Grade Glioma Removal on a Patient with Learning Disabilities

2017 ◽  
Vol 06 (01) ◽  
pp. 041-043 ◽  
Author(s):  
Andrej Vranic ◽  
Blaz Koritnik ◽  
Jasmina Markovic-Bozic
Keyword(s):  
Learning Disabilities ◽  
Case Report ◽  
Brain Tumors ◽  
Awake Craniotomy ◽  
Awake Surgery ◽  
Cortical Mapping ◽  
Low Grade ◽  
Low Grade Gliomas ◽  
Eloquent Areas ◽  
Slow Growing

Introduction Low-grade gliomas (LGG) are slow-growing primary brain tumors in adults, with high tropism for eloquent areas. Standard approach in treatment of LGG is awake craniotomy with intraoperative cortical mapping — a method which is usually used on adult and fully cooperative patients. Case Report We present the case of a patient with learning disabilities (PLD) who was operated for left insular LGG awake craniotomy, and intraoperative cortical mapping were performed and the tumor was gross totally removed. Conclusion Awake surgery for left insular LGG removal is challenging; however, it can be performed safely and successfully on PLD.

Usefulness of Motor Functional MRI Correlated to Cortical Mapping in Rolandic Low-Grade Astrocytomas

1999 ◽  
Vol 141 (1) ◽  
pp. 71-79 ◽  
Author(s):  
F. E. Roux ◽  
K. Boulanouar ◽  
J. P. Ranjeva ◽  
M. Tremoulet ◽  
P. Henry ◽  
...  
Keyword(s):  
Functional Mri ◽  
Cortical Mapping ◽  
Low Grade

scholarly journals Combining Gamma With Alpha and Beta Power Modulation for Enhanced Cortical Mapping in Patients With Focal Epilepsy

2020 ◽  
Vol 14 ◽  
Author(s):  
Mario E. Archila-Meléndez ◽  
Giancarlo Valente ◽  
Erik D. Gommer ◽  
João M. Correia ◽  
Sanne ten Oever ◽  
...  
Keyword(s):  
Focal Epilepsy ◽  
Cognitive Task ◽  
Cognitive Testing ◽  
Gamma Activity ◽  
Cortical Mapping ◽  
Beta Activity ◽  
Diagnostic Ability ◽  
Power Modulation ◽  
Eloquent Areas ◽  
Beta Power

About one third of patients with epilepsy have seizures refractory to the medical treatment. Electrical stimulation mapping (ESM) is the gold standard for the identification of “eloquent” areas prior to resection of epileptogenic tissue. However, it is time-consuming and may cause undesired side effects. Broadband gamma activity (55–200 Hz) recorded with extraoperative electrocorticography (ECoG) during cognitive tasks may be an alternative to ESM but until now has not proven of definitive clinical value. Considering their role in cognition, the alpha (8–12 Hz) and beta (15–25 Hz) bands could further improve the identification of eloquent cortex. We compared gamma, alpha and beta activity, and their combinations for the identification of eloquent cortical areas defined by ESM. Ten patients with intractable focal epilepsy (age: 35.9 ± 9.1 years, range: 22–48, 8 females, 9 right handed) participated in a delayed-match-to-sample task, where syllable sounds were compared to visually presented letters. We used a generalized linear model (GLM) approach to find the optimal weighting of each band for predicting ESM-defined categories and estimated the diagnostic ability by calculating the area under the receiver operating characteristic (ROC) curve. Gamma activity increased more in eloquent than in non-eloquent areas, whereas alpha and beta power decreased more in eloquent areas. Diagnostic ability of each band was close to 0.7 for all bands but depended on multiple factors including the time period of the cognitive task, the location of the electrodes and the patient’s degree of attention to the stimulus. We show that diagnostic ability can be increased by 3–5% by combining gamma and alpha and by 7.5–11% when gamma and beta were combined. We then show how ECoG power modulation from cognitive testing can be used to map the probability of eloquence in individual patients and how this probability map can be used in clinical settings to optimize ESM planning. We conclude that the combination of gamma and beta power modulation during cognitive testing can contribute to the identification of eloquent areas prior to ESM in patients with refractory focal epilepsy.

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