Identifying proximity to white matter language tracts with gradient-based intraoperative electrical mapping

Area of Science:

• Neurosurgery
• Neuroimaging
• Neurophysiology

Background:

• Intraoperative identification of language white matter tracts (WMTs) is crucial for preserving speech function during brain surgery.
• WMTs are visually imperceptible, posing a significant challenge for surgeons.
• Diffusion tensor imaging (DTI)-based tractography provides preoperative anatomical information but lacks real-time intraoperative guidance.

Purpose of the Study:

• To assess the feasibility of intraoperatively determining proximity to language WMTs.
• To correlate direct electrical stimulation (DES) intensity with the distance to language tracts.
• To support maximal tumor resection while minimizing language deficits.

Main Methods:

• Twenty-eight patients undergoing awake craniotomy for glioma resection were included.
• Preoperative language assessments and DTI-based language tract reconstruction were performed.
• Subcortical DES was applied along the tumor cavity border, with stimulation locations registered.

Main Results:

• A significant positive linear correlation (r = 0.57) was found between distance to language WMTs and DES electrical threshold.
• Stimulation evoking language interference required significantly lower intensity compared to non-interfering stimulation.
• Tumor characteristics did not significantly impact the distance-intensity correlation or language interference likelihood.

Conclusions:

• Intraoperative threshold-based electrical mapping is a feasible method for assessing language tract proximity.
• This technique can guide surgeons to balance maximal tumor resection with the preservation of language function.
• Bipolar stimulation demonstrated a significant correlation, suggesting its utility in intraoperative mapping.