SURG-13THE IMPACT OF MULTIMODAL FUNCTIONAL AND METABOLIC IMAGING OF HIGHLY-ELOQUENT BRAIN TUMORS ON FUNCTIONAL OUTCOME AND EXTENT OF RESECTION

Abstract

INTRODUCTION: Since functional outcome and extent of resection are of crucial importance for the adjuvant treatment and quality of life of patients with eloquently located gliomas, preoperative metabolic and functional imaging helps to delineate metabolically active and functionally relevant tumor parts. Here, the impact of multimodal preoperative imaging on functional outcome and extent of resection was prospectively investigated. METHODS: 54 patients with high grade gliomas (IV8: N = 46; IIIdegree: N = 8) adjacent to the primary motor cortex or the pyramidal tract were allocated to three groups for matched pair analysis. Group M("multimodal")was investigated by navigated transcranial magnetic stimulation (nTMS), functional MRI, DTI tractography and O-(2-[18F]Fluoroethyl)-L-tyrosine positron emission tomography (FET-PET) prior to surgery. Group T ("nTMS") received preoperative nTMS and FET-PET while patients of group S ("standard") were operated based on contrast-enhanced MRI. Intraoperatively, fluorescence-guidance (5-aminolevolinic acid), neuronavigation and direct cortical stimulation were applied in all groups. Motor function was assessed before surgery and at discharge. Any residual contrast enhancement in the postoperative MRI scan (0-48 hrs. after surgery) was regarded as tumor residual. RESULTS: 52% of the patients had preoperative motor deficits. At discharge, the paresis had improved in 26%, worsened in 7% and remained unchanged in 63%. Tumor size, localization and hemispheric dominance were even in all groups. Distance of tumor to the primary motor cortex/ pyramidal tract was significantly shorter in groups M/T compared to group S. Functional outcome was not significantly different between groups. The rate of complete resections was higher in groupsM/T. Moreover, the predictability of the resection extent by the surgeons was significantly higher in those groups. CONCLUSION: Preoperative metabolic and functional imaging of motor-eloquent gliomas improves the resection rates and enables a significantly higher predictability of the resection extent. Moreover, good functional outcome can be achieved whilst operating closer to primary motor areas