“…4(b)). This was already a more sophisticated approach compared to the usual contact visualization on a schematic representation of the central region [16].Nevertheless, the 3D analysis was complex and time consuming (about one hour for the definition of AROIS). In spite of the anatomic knowledge, it is always difficult even impossible to determine the exact location of contacts mostly for sulcus folders which support in special areas most of the primary motor cortex.…”
Section: Discussionmentioning
confidence: 99%
“…Afterwards the position of each electric contact is projected on a schematic representation of the central region, the mean position of the sulci and fissures seen on superficial computer tomography (CT) reconstructions [16]. Another possibility is the projection to a classical brain atlas such as the Talairach atlas [21] or the normalization of the patient information to Talairach space with a subsequent data projection onto a representative Magnetic Resonance Imaging (MRI) slice [19].…”
Electric chronic stimulation of the human motor cortex (ECSM) has been reported to alleviate chronic severe pain. However the mechanism of action of ECSM is still hypothetical. This is due mainly to the poor knowledge of, 1) the electric diffusion through the multiple structures beneath the epidural contacts (i.e. dura matter, cerebrospinal fluid space, arachnoid membrane, grey and white matter layers, pie mere and vascular tree), 2) the absence of consensus concerning the stimulation parameters (mono versus bipolar stimulation, cathodic or anodic current) and 3) the detailed cortical topography of the contacts. In this study we focused on the precise identification of the cortical areas covered by the electric contacts in a series of twelve patients operated on for ECSM. We propose a new automatic tool for topographic analysis able to compute 2D maps from the 3D anatomic MRI with 2) for the electrode contacts (Resume, Medtronic, USA), on post operative computerized tomography (CT). After getting white and gray matter membership maps by automatic segmentation, we produced a cortical mask to build a triangular mesh. We defined a homeomorphism between the 3D mesh and a subset of ℝ 2 and could apply in consequence the circle packing algorithm. We built depth maps (distance to the skull), distance-to-contact maps (distance to a given electrode contact) and anatomic structure maps. Results showed that it was easier to accurately define the location of the contact projection on the cortex allowing physicians to correlate the benefit with the topography. In particular, because of the unfolding, it was easier to integrate the cytoarchitectonics (i.e. the manually identified AROIs) knowledge in the analysis. Beyond the better understanding of ECSM and 3 Favreau JM et al
“…4(b)). This was already a more sophisticated approach compared to the usual contact visualization on a schematic representation of the central region [16].Nevertheless, the 3D analysis was complex and time consuming (about one hour for the definition of AROIS). In spite of the anatomic knowledge, it is always difficult even impossible to determine the exact location of contacts mostly for sulcus folders which support in special areas most of the primary motor cortex.…”
Section: Discussionmentioning
confidence: 99%
“…Afterwards the position of each electric contact is projected on a schematic representation of the central region, the mean position of the sulci and fissures seen on superficial computer tomography (CT) reconstructions [16]. Another possibility is the projection to a classical brain atlas such as the Talairach atlas [21] or the normalization of the patient information to Talairach space with a subsequent data projection onto a representative Magnetic Resonance Imaging (MRI) slice [19].…”
Electric chronic stimulation of the human motor cortex (ECSM) has been reported to alleviate chronic severe pain. However the mechanism of action of ECSM is still hypothetical. This is due mainly to the poor knowledge of, 1) the electric diffusion through the multiple structures beneath the epidural contacts (i.e. dura matter, cerebrospinal fluid space, arachnoid membrane, grey and white matter layers, pie mere and vascular tree), 2) the absence of consensus concerning the stimulation parameters (mono versus bipolar stimulation, cathodic or anodic current) and 3) the detailed cortical topography of the contacts. In this study we focused on the precise identification of the cortical areas covered by the electric contacts in a series of twelve patients operated on for ECSM. We propose a new automatic tool for topographic analysis able to compute 2D maps from the 3D anatomic MRI with 2) for the electrode contacts (Resume, Medtronic, USA), on post operative computerized tomography (CT). After getting white and gray matter membership maps by automatic segmentation, we produced a cortical mask to build a triangular mesh. We defined a homeomorphism between the 3D mesh and a subset of ℝ 2 and could apply in consequence the circle packing algorithm. We built depth maps (distance to the skull), distance-to-contact maps (distance to a given electrode contact) and anatomic structure maps. Results showed that it was easier to accurately define the location of the contact projection on the cortex allowing physicians to correlate the benefit with the topography. In particular, because of the unfolding, it was easier to integrate the cytoarchitectonics (i.e. the manually identified AROIs) knowledge in the analysis. Beyond the better understanding of ECSM and 3 Favreau JM et al
“…Au deuxième jour postopératoire, nous avons mis en route le stimulateur, en adoptant des paramètres de stimulation proposés dans la littérature existante (Nguyen et al, 2000 ;Nguyen et al, 1999 ;De Ridder et al, 2006 ;Litre et al, 2009).…”
Section: Suivi Et Réglage Du Stimulateurunclassified
“…Considerando que essa intervenção cirúrgica é utilizada para tratamento de dor neuropática refratária e que somente 50% dos pacientes se beneficiam com essa técnica (FAGUNDES-PEREYRA et al, 2010;NGUYEN et al, 2000), um melhor entendimento dos mecanismos de inibição do estímulo nociceptivo por ela desencadeados podem, posteriormente, colaborar com o aprimoramento dessa técnica, tornando-a mais efetiva e aumentar a sua probabilidade de sucesso em casos em que, até então, ela se mostrou ineficaz.…”
Section: Discussionunclassified
“…Nesse sentido, a estimulação do córtex motor (ECM), uma técnica terapêutica não destrutiva, ajustável e reversível, tem sido aplicada no tratamento de dores centrais complexas ou síndromes periféricas neuropáticas, resistentes à outros tratamentos (FAGUNDES-PEREYRA et al, 2010). Entretanto, a ECM falha em reverter a dor neuropática em aproximadamente um terço dos pacientes (NGUYEN et al, 2000), apontando para uma necessidade de prosseguir com a pesquisa nesse campo. Anteriormente, nosso grupo demonstrou que a ECM ativa a substância cinzenta periaquedutal mesencefália (PAG) (PAGANO et al, 2012).…”
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