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Shigeya Tanaka, Koichi Uetsuhara, Tetsuzou Tomosugi, Kouichi Moroki, Masahiko Yamada, Hideshi Toujou, Hideo Kawakami, and Munetoshi Sameshima

R ecise preoperative localization of brain lesions can assist the neurosurgeon in determining the best operative approach. We have developed a marking device that can be used with magnetic resonance (MR) imaging—guided localization of brain lesions. Description and Use of the Device The marking device was created from a circular acrylic plate 10 cm in diameter and 1.5-cm thick. Seventeen holes, × mm in diameter, were drilled in the shape of a cross at 1-cm intervals, filled with oil, and covered with acrylic lids. A sponge board 1-cm thick was attached

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Srikantan Nagarajan, Heidi Kirsch, Peter Lin, Anne Findlay, Susanne Honma, and Mitchel S. Berger

grasping can also be observed in MEG and can be localized to the precentral sulcus corresponding to hand motor cortex using adaptive spatial filtering methods. 13 , 39 , 40 , 50 , 51 Localization of movement-related magnetic fields using β-band ERD has been shown to be consistent with single ECD localization of motor cortex using the motor field. 50 , 51 However, few reports have examined the relative location of hand motor cortex with respect to hand somatosensory cortex and the overall sensitivity of using β-band ERD localization for preoperative localization of

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Helmut Buchner, Ludwig Adams, Achim Knepper, Rainer Rüger, Gabriel Laborde, Joachim M. Gilsbach, Irene Ludwig, Jürgen Reul, and Michael Scherg

improved, if functional localization is performed intraoperatively either by direct stimulation of the motor areas or by recording SSEP's from the cortical surface. 6, 11, 13, 29 However, these methods can only be applied intraoperatively and the information they yield is unavailable when the decision regarding an operation must be made or when the operation is being planned. Hence, the principal aim of our study was to test the feasibility of a new noninvasive method for the preoperative localization of the central sulcus and the functional hand area. Our results

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Peter T. Lin, Mitchel S. Berger, and Srikantan S. Nagarajan

T he preoperative localization of functionally viable brain tissue helps to guide neurosurgical planning in optimizing the region of resection while allowing for improved postsurgical neurological function. Various neuroimaging techniques, including MS and fMR imaging, are now available to preoperatively map functional brain organization. Coregistering structural MR imaging data to functional data acquired via MS or fMR imaging allows for the intraoperative creation of a neuronavigation system. 9 , 15 , 17 Magnetic source imaging has been shown to be

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Assaf Berger, Noa Cohen, Firas Fahoum, Mordekhay Medvedovsky, Aaron Meller, Dana Ekstein, Mony Benifla, Orna Aizenstein, Itzhak Fried, Tomer Gazit, and Ido Strauss

OBJECTIVE

Preoperative localization of seizure onset zones (SOZs) is an evolving field in the treatment of refractory epilepsy. Both magnetic source imaging (MSI), and the more recent EEG-correlated functional MRI (EEG-fMRI), have shown applicability in assisting surgical planning. The purpose of this study was to evaluate the capability of each method and their combination in localizing the seizure onset lobe (SL).

METHODS

The study included 14 patients who underwent both MSI and EEG-fMRI before undergoing implantation of intracranial EEG (icEEG) as part of the presurgical planning of the resection of an epileptogenic zone (EZ) during the years 2012–2018. The estimated location of the SL by each method was compared with the location determined by icEEG. Identification rates of the SL were compared between the different methods.

RESULTS

MSI and EEG-fMRI showed similar identification rates of SL locations in relation to icEEG results (88% ± 31% and 73% ± 42%, respectively; p = 0.281). The additive use of the coverage lobes of both methods correctly identified 100% of the SL, significantly higher than EEG-fMRI alone (p = 0.039) and nonsignificantly higher than MSI (p = 0.180). False-identification rates of the additive coverage lobes were significantly higher than MSI (p = 0.026) and EEG-fMRI (p = 0.027). The intersecting lobes of both methods showed the lowest false identification rate (13% ± 6%, p = 0.01).

CONCLUSIONS

Both MSI and EEG-fMRI can assist in the presurgical evaluation of patients with refractory epilepsy. The additive use of both tests confers a high identification rate in finding the SL. This combination can help in focusing implantation of icEEG electrodes targeting the SOZ.

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Assaf Berger, Noa Cohen, Firas Fahoum, Mordekhay Medvedovsky, Aaron Meller, Dana Ekstein, Mony Benifla, Orna Aizenstein, Itzhak Fried, Tomer Gazit, and Ido Strauss

OBJECTIVE

Preoperative localization of seizure onset zones (SOZs) is an evolving field in the treatment of refractory epilepsy. Both magnetic source imaging (MSI), and the more recent EEG-correlated functional MRI (EEG-fMRI), have shown applicability in assisting surgical planning. The purpose of this study was to evaluate the capability of each method and their combination in localizing the seizure onset lobe (SL).

METHODS

The study included 14 patients who underwent both MSI and EEG-fMRI before undergoing implantation of intracranial EEG (icEEG) as part of the presurgical planning of the resection of an epileptogenic zone (EZ) during the years 2012–2018. The estimated location of the SL by each method was compared with the location determined by icEEG. Identification rates of the SL were compared between the different methods.

RESULTS

MSI and EEG-fMRI showed similar identification rates of SL locations in relation to icEEG results (88% ± 31% and 73% ± 42%, respectively; p = 0.281). The additive use of the coverage lobes of both methods correctly identified 100% of the SL, significantly higher than EEG-fMRI alone (p = 0.039) and nonsignificantly higher than MSI (p = 0.180). False-identification rates of the additive coverage lobes were significantly higher than MSI (p = 0.026) and EEG-fMRI (p = 0.027). The intersecting lobes of both methods showed the lowest false identification rate (13% ± 6%, p = 0.01).

CONCLUSIONS

Both MSI and EEG-fMRI can assist in the presurgical evaluation of patients with refractory epilepsy. The additive use of both tests confers a high identification rate in finding the SL. This combination can help in focusing implantation of icEEG electrodes targeting the SOZ.

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Vincent C. Hinck and Guy L. Clifton

C ranial computerized tomography (CT) and skull radiography are the two neuroradiological examinations usually used for preoperative localization of brain lesions. Where lesions of the cerebral convexity are concerned, precise localization with CT has been completely dependent upon knowledge of the angle and level of cut because there are no bone or cisternal CT landmarks to provide useful anatomic points of reference during surgery. Angle and level of cut are generally estimated on CT and then transposed to a skull radiograph (and for that reason are

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Lourens Penning

the vertex (1); the rolandic fissure (2); and the outline of the field of view (3). By superimposing the OM plane (left) on the tumor plane (right) the line connecting both external auditory meatus on the OM plane has been transferred to the tumor plane. The location of the tumor with respect to the perpendicular auditory meatus plane (4: through the external auditory meatus perpendicular to the OM plane) is now known. Technique In order to prevent erroneous preoperative localization of a convexity tumor on the scalp of a patient, the exact position

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Michael J. Strong, Julianne Santarosa, Timothy P. Sullivan, Noojan Kazemi, Jacob R. Joseph, Osama N. Kashlan, Mark E. Oppenlander, Nicholas J. Szerlip, Paul Park, and Clay M. Elswick

Fiducial Metallic Marker (Screw or Gold) Placement This technique is widely used in radiation oncology to localize tumors before stereotactic radiosurgery, 11–13 and it has been utilized as a method for preoperative localization of the surgical level before a surgical intervention. 5 , 13–15 In a technical note, Marichal et al. describe their experience with this technique. 13 Briefly, the patient is brought to the interventional suite where the procedure is performed under conscious sedation. The patient is positioned prone and a helical CT obtains axial images in

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Mendel Castle-Kirszbaum, Julian Maingard, Tony Goldschlager, and Ronil V. Chandra

with dyes, K-wires, and polymethylmethacrylate injections have been used, but these have significant disadvantages that have limited their mainstream adoption. Here, we present our technique for preoperative marking of spinal pathology using CT-guided deployment of a pushable radiopaque vascular coil into the vertebral periosteum, which facilitates fast and accurate intraoperative localization. Surgical Technique The patient is selected for preoperative localization by the surgeon or radiologist. This typically occurs for patients in whom standard intraoperative