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Localization of functionally vital cortex in the individual patient: correlation between invasive and non-invasive methods

English title Localization of functionally vital cortex in the individual patient: correlation between invasive and non-invasive methods
Applicant Schaller Karl
Number 122073
Funding scheme Project funding (Div. I-III)
Research institution Service de Neurochirurgie Département des Neurosciences Cliniques Hôpitaux Universitaires de Genève
Institution of higher education University of Geneva - GE
Main discipline Neurophysiology and Brain Research
Start/End 01.12.2008 - 30.09.2012
Approved amount 375'000.00
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Keywords (10)

brain imaging; brain functions; epilepsy; brain tumors; neurosurgery; intrinsic brain tumors; presurgical diagnostics; functional imaging; electrical source imaging; cortical stimulation

Lay Summary (English)

Lead
Lay summary
An essential task in the surgical treatment of brain lesions is to be able to propose resection margins that would allow removing the lesion as complete as possible while avoiding neurological deficits. In order to achieve this goal the pre-surgical planning includes precise localization of the lesion and the precise definition of the functionally important cortical areas surrounding this lesion. Such pre-surgical planning is particularly essential in tumor resection and in resection of epileptogenic cortex. In the first case the location of the lesion is readily available, and the main task consists in attaining an adequate balance between radicality of resection and avoidance of new neurological deficits. In the second case, the epileptogenic zone has to be defined first by a presurgical workup and has to be separated from functional relevant areas.The gold standard in the presurgical planning for lesion resection is still largely based on invasive methods, either intraoperatively through direct cortical stimulation in the awake patient (in case of tumors), or extraoperatively through stimulation mapping of implanted subdural electrodes (in case of epilepsy). These invasive brain mapping techniques are rather difficult to perform and require large investments from both the patient as well as the medical staff. Several different non-invasive functional neuroimaging techniques have recently been developed and could potentially replace the invasive methods. However, studies that systematically compare these methods with electrocortical stimulation in individual patients are still largely missing, particularly with respect to localization of higher cognitive functions. Group studies are mostly performed. An important missing piece in these validation studies is the reliable co-registration of the different imaging results with the exact localization based on the implanted electrodes during electrocortical stimulation.The project aims to test advanced non-invasive brain imaging techniques for their utility to localize pathological as well as functionally relevant cortex in the individual patient and not only in group studies. Two methods will be tested, funbctional resonance imaging (fMRI) and electric source imaging (ESI). The two methods complement each other in many respect, most importantly in providing good spatial (fMRI) and good temporal (ESI) resolution. In the project we will develop recording and analysis methods for fMRI and ESI and test them with respect to localization precision against the intracranial electrocortical stimulation. The following main work-packages were defined : 1. Epileptic focus localization with fMRI and with ESI, validated by chronic intracranial recording.2. Localization of sensorimotor cortex with fMRI and with ESI, validated by electrocortical stimulation (ECS).3. Localization of language areas with fMRI and with ESI, validated by ECS 4. Multimodal image fusioning of functional maps with by intraoperative 2D- and 3D-digital photographs.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Electroencephalographic source imaging: a prospective study of 152 operated epileptic patients
Brodbeck Verena (2011), Electroencephalographic source imaging: a prospective study of 152 operated epileptic patients, in Brain, 134, 2887-2897.
With or without spikes: localization of focal epileptic activity by simultaneous electroencephalography and functional magnetic resonance imaging
Grouiller Frederic (2011), With or without spikes: localization of focal epileptic activity by simultaneous electroencephalography and functional magnetic resonance imaging, in Brain, 134, 2867-2886.

Awards

Title Year
Prix de la Société Suisse de Neurophysiologie clinique 2011
Trainee Abstract Award, HBM 2010. 2010

Associated projects

Number Title Start Funding scheme
140332 Imaging large scale neuronal networks in epilepsy 01.05.2012 SPUM
182497 Mapping the brain networks of the bodily and cognitive self for the prediction of personality deficits following brain surgery 01.01.2019 Project funding (Div. I-III)
146633 Non-invasive analysis of language network connectivity by EEG, fMRI, and DTI for the planning of brain surgery 01.10.2013 Project funding (Div. I-III)

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