Role of Intraoperative Magnetic Resonance Imaging in Meningioma Surgery

Object: Intraoperative magnetic resonance imaging (iMRI) has gained importance in the treatment of gliomas and sellar tumors. In intracranial meningiomas, the extent of surgical tumor removal influences the risk of tumor recurrence. Complex meningiomas located at the skull base or near eloquent brain regions show higher recurrence rates, morbidity, and mortality. The aim of this study was to evaluate whether iMRI contributes to higher surgical resection extent in these tumors.

Methods: Patients undergoing meningioma resection using iMRI from January 2007 to January 2011 were included in this study. The indication for iMRI-guided tumor resection included patients presenting with meningiomas located in the skull base or compressing eloquent brain areas in which a radical resection was considered to be difficult. Intraoperative 0.15-Tesla MRI-scan (PoleStar®, Medtronic Navigation, Louisville, CO, USA) was performed before and after maximal possible resection using standard microsurgical and neuronavigation techniques. All patients underwent fluorescence-guided resection. Following data were analyzed: tumor localization, histological grade, Simpson resection grade, duration of the procedure, iMRI scan time, iMRI findings, resection extended based on postresection iMRI, hospitalization time, surgical complications and outcome, and MRI follow-up 2 to 27 months postoperative.

Results: In this study 27 consecutive patients undergoing meningioma resection using iMRI were included. In this series, only one patient (3.4%) underwent resection of tumor remnant after iMRI, though without improvement of the Simpson resection grade. Temporary neurologic deficits postoperatively were found in 8 patients (27.6%), whereas 11 patients (37.9%) had permanent postoperative neurologic deficits. In one case (3.4%) a fatal postoperative bleeding occurred, which was not detected by iMRI.

Conclusions: Our results show that iMRI has no influence on intraoperative strategy, in terms of resection grade and on detection of early postoperative complications; therefore its benefit in meningioma surgery is doubtful.