Using Histopathology to Assess the Reliability of Intraoperative Magnetic Resonance Imaging in Guiding Additional Brain Tumor Resection: A Multicenter Study

BACKGROUND Intraoperative magnetic resonance imaging (iMRI) is a powerful tool for guiding brain tumor resections, provided that it accurately discerns residual tumor. OBJECTIVE To use histopathology to assess how reliably iMRI may discern additional tumor for a variety of tumor types, independent of the indications for iMRI. METHODS A multicenter database was used to calculate the odds of additional resection during the same surgical session for grade I to IV gliomas and pituitary adenomas. The reliability of iMRI for identifying residual tumor was assessed using histopathology of tissue resected after iMRI. RESULTS Gliomas (904/1517 cases, 59.6%) were more likely than pituitary adenomas (176/515, 34.2%) to receive additional resection after iMRI (P