Cortical mapping and frameless stereotactic navigation in the high-field intraoperative magnetic resonance imaging suite

Abstract

Frameless stereotactic neuronavigation provides tracking of surgical instruments on radiographic images and orients the surgeon to tumor margins at surgery. Bipolar electrical stimulation mapping (ESM) delineates safe limits for resection of brain tumors adjacent to eloquent cortex. These standard techniques could complement the capability of intraoperative MR (iMR) imaging to evaluate for occult residual disease during surgery and promote more complete tumor removal. The use of frameless neuronavigation in the high-field iMR imaging suite requires that a few pieces of standard equipment be replaced by nonferromagnetic instruments. Specific use of ESM in a high-field iMR imaging suite has not been reported in the literature. To study whether frameless neuronavigation and electrical stimulation mapping could be successfully integrated in the high-field iMR imaging suite, the authors employed these modalities in 10 consecutive cases involving patients undergoing conscious craniotomy for primary brain tumors located in or adjacent to eloquent cortices. Equipment included a custom high-field MR imaging–compatible head holder and dynamic reference frame attachment, a standard MR imaging–compatible dynamic reference frame, a standard MR imaging machine with a table top that could be translated to a pedestal outside the 5-gauss line for the operative intervention, and standard neuronavigational and cortical stimulation equipment. Both ESM and frameless stereotactic guidance were performed outside the 5-gauss line. The presence of residual neoplasm was evaluated using iMR imaging; resection was continued until eloquent areas were encountered or iMR imaging confirmed complete removal of any residual tumor. Mapping identified essential language (5 patients), sensory (6), and motor (7) areas. The combined use of frameless stereotactic navigation, ESM, and iMR imaging resulted in complete radiographic resection in 7 cases and resection to an eloquent margin in 3 cases. Postoperative MR imaging confirmed final iMR imaging findings. No patient experienced a permanent new neurological deficit. Familiar techniques such as frameless navigation and ESM can be rapidly, inexpensively, safely, and effectively integrated into the high-field iMR imaging suite.

Contribution of combined intraoperative electrophysiological investigation with 3-T intraoperative MRI for awake cerebral glioma surgery: comprehensive review of the clinical implications and radiological outcomes

“…The rate of GTR achieved in our study is similar to the rates reported previously. 16,19,21,33,35 Although OS and PFS were different between the LGG and HGG groups, the relatively short observational period (a mean of 24.8 months) prevents us from making any definitive conclusion for the LGG group based on these results. Nonetheless, to our knowledge this is the first study to analyze the clinical outcomes, and the follow-up period is considerably longer than in the previous reports.…”

Awake craniotomy for gliomas in a high-field intraoperative magnetic resonance imaging suite: analysis of 42 cases

“…3,11,12,13,24 In the series described by Leuthardt et al 11 and the case report by Parney et al, 13 an overhead moveable magnet was used for scanning. However, in the other series, 3,12,24 including ours, the position of the magnet was fixed on the floor, and the patient was moved toward the scanner for intraoperative scans. The overall operative time in our patient population was 7.3 hours, which is longer than the times reported in the other published studies.…”

“…2,3,[11][12][13][14]18,[22][23][24] In some earlier work we showed that intraoperative multimodality electrophysiological mapping can be seamlessly incorporated into high-field iMRI for tumor resections. 15 Initially when we started the procedure of combining awake craniotomy with high-field iMRI, there were a number of challenges to overcome, including patient comfort and position as well as new draping and anesthetic techniques unique to the iMRI environment.…”

“…A few studies have described the awake craniotomy procedure in a high-field (1.5 T) iMRI suite. 3,[11][12][13]24 Our group has previously demonstrated the safety of combining multimodality electrophysiological monitoring with high-field (1.5 T) iMRI for the resection of gliomas in eloquent brain areas. 5 Here we report on a consecutive series of 42 cases (41 patients) treated with awake craniotomy in the high-field iMRI suite and discuss our experience in this patient population.…”

Simultaneous Use of Functional Tractography, Neuronavigation-Integrated Subcortical White Matter Stimulation and Intraoperative Magnetic Resonance Imaging in Glioma Surgery: Technical Note

“…The risk of permanent deficit is approximately 5%, according to the largest series in the literature using subcortical white matter stimulation for perirolandic gliomas [9] . The safety of using electrophysiological monitoring in the intraoperative magnetic environment has recently been described [10,11] . The purpose of this report is to present the feasibility and advantages of integrating functional navigation and direct cortical and subcortical stimulation using a single monopolar probe.…”