NS-11: LOW-FIELD POLESTAR N20 MOBILE iMR SYSTEM AS AN ADJUNCT FOR PEDIATRIC BRAIN TUMOR RESECTION: FEASIBILITY, USEFULNESS AND SAFETY

INTRODUCTION: The value of extensive tumor resection in pediatric brain tumours is well known. Image-guided surgery can help to achieve maximal safe resections. We analyze our experience with low-field PoleStar N20 iMR system in 17 pediatric patients, focusing on its feasibility in this population, its usefulness, and its accordance with the early postoperative high-field MR study. MATERIAL AND METHODS: Seventeen iMR-guided procedures were performed between 2011 and 2016. Children were between 8 months and 16 years old. Patientś head was fixed in a MR-compatible head-clamp or positioned on a plastic headrest depending on the age. Prone, supine or lateral positioning was chosen depending on tumor location. After resection iMR images were acquired to detect residual tumour. Early 3-T postoperative MR scan were obtained in all cases and compared to intraoperative low-field images. RESULTS: Patient positioning resulted easier than in adults due to their smaller size. iMR surgery took extra time for setup and scanning (between 15-175 min, mean 110min). In six cases, intraoperative images showed residual tumor and surgery was continued until complete resection was verified in a new scan. Complete resection was achieved in 15 cases (88.23%). We had neither intraoperative adverse events nor craniotomy infections related to the use of this equipment. There was a good correlation between Polestar images and high field 3-T postoperative control images. CONCLUSION: The Polestar N20 iMR is feasible and safe as an adjunct for pediatric brain tumor resection. It provides enough quality images to detect residual tumor and update neuronavigation.