Planning Brain Tumor Resection Using a Probabilistic Atlas of Cortical and Subcortical Structures Critical for Functional Processing: A Proof of Concept

Abstract

BACKGROUND Functional preoperative planning for resection of intrinsic brain tumors in eloquent areas is still a challenge. Predicting subcortical functional framework is especially difficult. Direct electrical stimulation (DES) is the recommended technique for resection of these lesions. A reliable probabilistic atlas of the critical cortical epicenters and subcortical framework based on DES data was recently published. OBJECTIVE To propose a pipeline for the automated alignment of the corticosubcortical maps of this atlas with T1-weighted MRI. METHODS To test the alignment, we selected 10 patients who underwent resection of brain lesions by using DES. We aligned different cortical and subcortical functional maps to preoperative volumetric T1 MRIs (with/without gadolinium). For each patient we quantified the quality of the alignment, and we calculated the match between the location of the functional sites found at DES and the functional maps of the atlas. RESULTS We found an accurate brain extraction and alignment of the functional maps with both the T1 MRIs of each patient. The matching analysis between functional maps and functional responses collected during surgeries was 88% at cortical and, importantly, 100% at subcortical level, providing a further proof of the correct alignment. CONCLUSION We demonstrated quantitatively and qualitatively the reliability of this tool that may be used for presurgical planning, providing further functional information at the cortical level and a unique probabilistic prevision of distribution of the critical subcortical structures. Finally, this tool offers the chance for multimodal planning through integrating this functional information with other neuroradiological and neurophysiological techniques.

Understanding Variable Motor Responses to Direct Electrical Stimulation of the Human Motor Cortex During Brain Surgery

“…While traditional DES implies cortical surface stimulation, the advent of subcortical mapping in the late 20 th century has also proven quite useful (26,27,30,33,48,62,70,71). Subcortical mapping evaluates for white matter involvement throughout the duration of the surgery, and allows the surgeon to safely resect tissue deep to the cortex without violating irreparable tracts.…”

Neural Connectivity: How to Reinforce the Bidirectional Synapse Between Basic Neuroscience and Routine Neurosurgical Practice?

“…This can be helpful for neurosurgeons to predict whether the patient will recover or not according to the extent of resection, especially by highlighting the structures with a low potential of reorganization, such as the subcortical connectivity-the socalled "minimal common brain" mentioned above (27). To facilitate presurgical planning by predicting the distribution of essential neural connections to be preserved, a tool has recently been proposed for a practical use: it allows automated alignment of the cortico-subcortical maps of this probabilistic atlas with T1weighted MRI of a given patient (57). These data can also be used to estimate before surgery the extent of resection thanks to a probabilistic map of tumor resectability, computed on the basis of postoperative residual glioma voluntarily left because of invading critical structures identified by intraoperative ESM (58).…”

Surgical management of Glioma Grade 4: technical update from the neuro-oncology section of the Italian Society of Neurosurgery (SINch®): a systematic review

“…Contemporary technological and conceptual innovations have thus improved the safety of surgical resection, while expanding the surgical options and indications for GG4 surgical treatment [ 20 , 21 ]. Several techniques currently used during surgery, such as intraoperative ultrasound (iUS), cortical mapping, sodium fluorescein [ 22 ] and 5-ALA fluorescence (5-aminolevulinic acid), tend to favor higher rates of total resection, with apparent increased survival [ 17 , 18 , 23 ].…”