INFORMATION-GUIDED SURGERY USING INTRAOPERATIVE MRI AND FUNCTIONAL MAPPING FOR GLIOMAS.

BACKGROUND: Contemporary technological developments revolutionized surgical management of intraaxial brain tumors. The intraoperative MRI (iMRI) and updated neuronavigation permitted for neurosurgeons to perform tumor resection under precise guidance. Neurophysiological monitoring and brain mapping allows precise localization of the cerebral functions and preservation of the important function during removal of the tumor. Intraoperative histopathological diagnosis allows fast direct investigation for identification of the neoplastic cells. Incorporation of these adjuncts provides for the surgeon an opportunity to perform aggressive glioma resection with minimal risk of neurological morbidity. The present report highlights our experience with information-guided surgical management of gliomas using low magnetic field strength iMRI in the intelligent operating theater with an emphasis on tumor resection rate and outcome. METHODS: From 2000 to 2013, 1234 surgeries for intracranial lesions were performed with the use of intraoperative MRI (iMRI) with low magnetic field strength of 0.3 Tesla, updated neuronavigation, serial intraoperative histopathological investigations, and neurophysiological monitoring (1000 gliomas, 45 cavernous malformations, 34 pituitary tumors, and other tumors). Newly-diagnostic gliomas followed more than one year were 533 cases (8 biopsies, 525 craniotomy) and WHO grade-II, -III, and -IV gliomas resected were 197, 150, and 170 cases, respectively (8 not specified). Adjuvant therapy for grade-II, -III, and IV patients was radiation (RT) and/or ACNU chemotherapy if resection rate were less than 90%, RT + ACNU, and RT + TMZ, respectively. RESULTS: Mean resection rates (RR) of grade-II, -III, and -IV were 87.7%, 89.5%, and 93.7%, respectively (P = 0.0004). Five-year and 10-year- survival rates of grade-II patients were 91.7% and 78.3%, those of grade-III patients were 76.9% and 71.9%, and 5-year survival of grade-IV patients were 19% (P = 0.042). RR of all-grade patients underwent awake craniotomy with functional mapping (AC: n = 174) and general anesthesia without functional mapping (GA: n = 351) were 86% and 93% (P < 0.001), and 5-year SR of AC and GA were 81.8% and 60.2% (P < 0.0001). However, RR of grade-II and -III patients underwent AC and GA were 85% and 92%, and 5-year SR of them were not significantly different (90% vs. 83%: P > 0.05). RR of patients with iMRI and without iMRI were significantly different in grade IV (94% vs. 78%: P < 0.0001) but not in grade II and III (89% vs. 87%: P > 0.05)). Overall survival of Grade-IV patients with iMRI and without MRI were 21 months and 11 months (P = 0.037). CONCLUSIONS: Information-guided management of gliomas using functional mapping and low-field-strength iMRI provides a good opportunity for maximal possible tumor resection, and may result in survival advantage. SECONDARY CATEGORY: Imaging.