BrainTRACE (Brain Tumor Registration and Cortical Electrocorticography): A Novel Tool for Localizing Electrocorticography Electrodes in Patients with Brain Tumors.

Background: Intraoperative electrocorticography (ECoG) plays a critical role in clinical care and neuroscience research, enabling precise mapping of functional cortex. However, localizing subdural electrodes in patients with brain tumors presents unique challenges due to altered neuroanatomy and the impracticality of acquiring extraoperative computed tomography (CT). To address this gap, we developed BrainTRACE, a novel MATLAB tool that combines magnetic resonance imaging (MRI), cortical vascular reconstructions, and intraoperative photography for accurate subdural electrode grid placement.

Methods: Preoperative MRI, cortical photography, and subdural electrode array data were recorded from patients with diffuse glioma and brain metastasis. BrainTRACE generated three-dimensional cortical surfaces, integrated vascular reconstructions, and enabled precise placement of electrode grids. Each electrode was placed based on cortical anatomy and vascular landmarks informed by intraoperative photographs. Novice and expert-level proficiency were quantified.

Results: Expert users achieved high consistency and accuracy, with an intraclass correlation coefficient (ICC) of 0.934 and a mean deviation of 4.3 mm from consensus placements. Novice users demonstrated lower reliability (ICC = 0.399) and greater variability, averaging a 16.3 mm deviation from consensus. These findings highlight the non-trivial nature of intraoperative ECoG localization, which requires neuroanatomical expertise for successful grid placement.

Conclusion: BrainTRACE enables accurate localization of intraoperative ECoG electrodes in brain tumor patients. By integrating anatomical images, intraoperative photographs, and vascular mapping, the tool addresses challenges posed by tumor-induced artifacts. While requiring that users have cortical neuroanatomical expertise, BrainTRACE provides a practical tool for neurosurgical and neuroscience applications, including brain malignancy, epilepsy, and deep brain stimulation procedures. BrainTRACE is freely available to researchers (https://github.com/dbrang/BrainTRACE).