Intraoperative MRI guidance and extent of resection in glioma surgery: a randomised, controlled trial

Background Intraoperative MRI is increasingly used in neurosurgery, although there is little evidence for its use. We aimed to assess efficacy of intraoperative MRI guidance on extent of resection in patients with glioma. Methods In our prospective, randomised, parallel-group trial, we enrolled adults (>= 18 years) with contrast enhancing gliomas amenable to radiologically complete resection who presented to Goethe University (Frankfurt, Germany). We randomly assigned patients (1:1) with computer-generated blocks of four and a sealed-envelope design to undergo intraoperative MRI-guided surgery or conventional microsurgery (control group). Surgeons and patients were unmasked to treatment group allocation, but an independent neuroradiologist was masked during analysis of all preoperative and postoperative imaging data. The primary endpoint was rate of complete resections as established by early postoperative high-field MRI (1.5 T or 3.0 T). Analysis was done per protocol. This study is registered with ClinicalTrials. gov, number NCT01394692. Findings We enrolled 58 patients between Oct 1, 2007, and July 1, 2010. 24 (83%) of 29 patients randomly allocated to the intraoperative MRI group and 25 (86%) of 29 controls were eligible for analysis (four patients in each group had metastasis and one patient in the intraoperative MRI group withdrew consent after randomisation). More patients in the intraoperative MRI group had complete tumour resection (23 [96%] of 24 patients) than did in the control group (17 [68%] of 25, p=0.023). Postoperative rates of new neurological deficits did not differ between patients in the intraoperative MRI group (three [13%] of 24) and controls (two [8%] of 25, p=1.0). No patient for whom use of intraoperative MRI led to continued resection of residual tumour had neurological deterioration. One patient in the control group died before 6 months. Interpretation Our study provides evidence for the use of intraoperative MRI guidance in glioma surgery: such imaging helps surgeons provide the optimum extent of resection. Funding None.