Efficacy and safety of intraoperative MRI in glioma surgery: a systematic review and meta-analysis of prospective randomized controlled trials

OBJECTIVE Maximum extent of resection in glioma yields enhanced survival outcomes. The contemporary literature presents contradictory results regarding the benefit of intraoperative MRI (iMRI). This meta-analysis aimed to investigate the efficacy and safety of iMRI-guided surgery. METHODS The authors searched the PubMed, Embase, and Cochrane Reviews databases for eligible prospective randomized controlled trials through the end of February 2024. Endpoints were extent of resection, progression-free survival (PFS), overall survival, neurological functioning, and surgical complications. Individual patient data regarding PFS were reconstructed using the R package IPDfromKM. RESULTS From 1923 identified results, 3 randomized controlled trials with 384 patients met the inclusion criteria. Extended resections after iMRI were performed in 29.2% of the iMRI cases. Intraoperative MRI–guided glioma surgery (OR 5.40, 95% CI 3.25–8.98; p < 0.00001) outperformed conventional navigation-guided surgery in attaining gross-total resection (GTR). In patients in whom a GTR was achieved, the median time to progression was 16.0 months (95% CI 12.3–19.7 months), while the median PFS in patients with a subtotal resection was 9.7 months (95% CI 6.9–12.5 months) (p < 0.001). Despite increased GTR rates, postoperative neurological deterioration was equal among the iMRI and control groups (OR 1.0, 95% CI 0.6–1.7; p = 0.91, I 2 = 0%). Intraoperative MRI use prolongs surgery by 42 minutes on average (95% CI 3.3–80.7 minutes; p = 0.03, I 2 = 56%). The risk of postoperative intracranial hemorrhage (OR 1.9, 95% CI 0.2–16.9; p = 0.55, I 2 = 0%) was not increased, while in one study significantly increased infections were observed in the iMRI arm. CONCLUSIONS Intraoperative MRI outperforms conventional surgery in achieving complete glioma resections of all contrast-enhancing tumor portions, enhancing PFS without added risk. Intraoperative MRI is a tool that facilitates these aims without reducing safety in terms of neurological deficits and surgical complications.