3D visualization of subdural electrode shift as measured at craniotomy reopening

LaViolette, Peter S.; Rand, Scott D.; Ellingson, Benjamin M.; Raghavan, Manoj; Lew, Sean M.; Schmainda, Kathleen M.; Mueller, Wade

doi:10.1016/j.eplepsyres.2011.01.011

Cited by 35 publications

(37 citation statements)

References 21 publications

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“…In all patients, intraoperative pictures were taken with a digital camera before dural closure as well as after re-opening, to confirm the spatial accuracy of electrode display on the 3D brain surface reconstructed from MRI (Nagasawa et al, 2011; Wu et al, 2011). Nonetheless, a minor spatial error in coregistration of MRI and subdural electrodes (LaViolette et al, 2011) could not be ruled out in non-visualized occipital regions in some patients in the present study.…”

Section: Methodsmentioning

confidence: 63%

Independent predictors of neuronal adaptation in human primary visual cortex measured with high-gamma activity

et al. 2012

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Neuronal adaptation is defined as a reduced neural response to a repeated stimulus and can be demonstrated by reduced augmentation of event-related gamma activity. Several studies reported that variance in the degree of gamma augmentation could be explained by pre-stimulus low-frequency oscillations. Here, we measured the spatio-temporal characteristics of visually-driven amplitude modulations in human primary visual cortex using intracranial electrocorticography. We determined if interstimulus intervals or pre-stimulus oscillations independently predicted local neuronal adaptation measured with amplitude changes of high-gamma activity at 80–150 Hz. Participants were given repetitive photic stimuli with a flash duration of 20 µsec in each block; the inter-stimulus interval was set constant within each block but different (0.2, 0.5, 1.0 or 2.0 sec) across blocks. Stimuli elicited augmentation of high-gamma activity in the occipital cortex at about 30 to 90 msec, and high-gamma augmentation was most prominent in the medial occipital region. High-gamma augmentation was subsequently followed by lingering beta augmentation at 20–30 Hz and high-gamma attenuation. Neuronal adaptation was demonstrated as a gradual reduction of high-gamma augmentation over trials. Multivariate analysis demonstrated that a larger number of prior stimuli, shorter inter-stimulus interval, and pre-stimulus high-gamma attenuation independently predicted a reduced high-gamma augmentation in a given trial, while pre-stimulus beta amplitude or delta phase had no significant predictive value. Association between pre-stimulus high-gamma attenuation and a reduced neural response suggests that high-gamma attenuation represents a refractory period. The local effects of pre-stimulus beta augmentation and delta phase on neuronal adaptation may be modest in primary visual cortex.

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Section: Methodsmentioning

confidence: 63%

Independent predictors of neuronal adaptation in human primary visual cortex measured with high-gamma activity

et al. 2012

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“…Several methods have been developed to localize the implanted electrodes in relation to cortical surface structures, including those based on digital photography (Mahvash et al, 2007; Wellmer et al, 2002), X-ray radiographs (Miller et al, 2007, 2010), computerized tomography (CT) (Dykstra et al, 2011; Grzeszczuk et al, 1992; Hermes et al, 2010; Hunter et al, 2005; LaViolette et al, 2011a; Morris et al, 2004; Sebastiano et al, 2006; Tao et al, 2009; Wang et al, 2005; Winkler et al, 2000), magnetic resonance imaging (MRI) (Bootsveld et al, 1994; Kovalev et al, 2005; Morris et al, 2004; Schulze-Bonhage et al, 2002), and multiple image sets (Dalal et al, 2008). …”

Section: Introductionmentioning

confidence: 99%

Localization of dense intracranial electrode arrays using magnetic resonance imaging

et al. 2012

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Intracranial electrode arrays are routinely used in the pre-surgical evaluation of patients with medically refractory epilepsy, and recordings from these electrodes have been increasingly employed in human cognitive neurophysiology due to their high spatial and temporal resolution. For both researchers and clinicians, it is critical to localize electrode positions relative to the subject-specific neuroanatomy. In many centers, a post-implantation MRI is utilized for electrode detection because of its higher sensitivity for surgical complications and the absence of radiation. However, magnetic susceptibility artifacts surrounding each electrode prohibit unambiguous detection of individual electrodes, especially those that are embedded within dense grid arrays. Here, we present an efficient method to accurately localize intracranial electrode arrays based on pre- and post-implantation MR images that incorporates array geometry and the individual's cortical surface. Electrodes are directly visualized relative to the underlying gyral anatomy of the reconstructed cortical surface of individual patients. Validation of this approach shows high spatial accuracy of the localized electrode positions (mean of 0.96 mm±0.81 mm for 271 electrodes across 8 patients). Minimal user input, short processing time, and utilization of radiation-free imaging are strong incentives to incorporate quantitatively accurate localization of intracranial electrode arrays with MRI for research and clinical purposes. Co-registration to a standard brain atlas further allows inter-subject comparisons and relation of intracranial EEG findings to the larger body of neuroimaging literature.

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“…Subdural grid and strip electrodes are more prone to suboptimal positioning since they are sometimes passed through a bur hole or beyond craniotomy edges. 10 Accurate placement of invasive EEG electrodes is important for correctly identifying a seizure onset zone that may be appropriate for resection.…”

mentioning

confidence: 99%

Intraoperative computed tomography for intracranial electrode implantation surgery in medically refractory epilepsy

Lee¹,

Zwienenberg-Lee²,

Seyal

et al. 2015

JNS

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A pproximAtely one-third of newly diagnosed epilepsy cases are refractory to medical management, and patients in these cases may be appropriate candidates for surgical intervention. 9,15 The patients often undergo intracranial electroencephalography (EEG) monitoring via implanted subdural and/or depth electrodes to identify a seizure onset zone. Subdural electrode strips and grids are sometimes implanted through bur holes or ObJect Accurate placement of intracranial depth and subdural electrodes is important in evaluating patients with medically refractory epilepsy for possible resection. Confirming electrode locations on postoperative CT scans does not allow for immediate replacement of malpositioned electrodes, and thus revision surgery is required in select cases. Intraoperative CT (iCT) using the Medtronic O-arm device has been performed to detect electrode locations in deep brain stimulation surgery, but its application in epilepsy surgery has not been explored. In the present study, the authors describe their institutional experience in using the O-arm to facilitate accurate placement of intracranial electrodes for epilepsy monitoring. MethODS In this retrospective study, the authors evaluated consecutive patients who had undergone subdural and/or depth electrode implantation for epilepsy monitoring between November 2010 and September 2012. The O-arm device is used to obtain iCT images, which are then merged with the preoperative planning MRI studies and reviewed by the surgical team to confirm final positioning. Minor modifications in patient positioning and operative field preparation are necessary to safely incorporate the O-arm device into routine intracranial electrode implantation surgery. The device does not obstruct surgeon access for bur hole or craniotomy surgery. Depth and subdural electrode locations are easily identified on iCT, which merge with MRI studies without difficulty, allowing the epilepsy surgical team to intraoperatively confirm lead locations. reSultS Depth and subdural electrodes were implanted in 10 consecutive patients by using routine surgical techniques together with preoperative stereotactic planning and intraoperative neuronavigation. No wound infections or other surgical complications occurred. In one patient, the hippocampal depth electrode was believed to be in a suboptimal position and was repositioned before final wound closure. Additionally, 4 strip electrodes were replaced due to suboptimal positioning. Postoperative CT scans did not differ from iCT studies in the first 3 patients in the series and thus were not obtained in the final 7 patients. Overall, operative time was extended by approximately 10-15 minutes for O-arm positioning, less than 1 minute for image acquisition, and approximately 10 minutes for image transfer, fusion, and intraoperative analysis (total time 21-26 minutes). cONcluSiONS The O-arm device can be easily incorporated into routine intracranial electrode implantation surgery in standard-sized operating rooms. The technique provides accurate 3D v...

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3D visualization of subdural electrode shift as measured at craniotomy reopening

Cited by 35 publications

References 21 publications

Independent predictors of neuronal adaptation in human primary visual cortex measured with high-gamma activity

Independent predictors of neuronal adaptation in human primary visual cortex measured with high-gamma activity

Localization of dense intracranial electrode arrays using magnetic resonance imaging

Intraoperative computed tomography for intracranial electrode implantation surgery in medically refractory epilepsy

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