Craniotomy for tumor treatment in an intraoperative magnetic resonance imaging unit

OBJECTIVE: The complex three-dimensional anatomic features of the brain and its vulnerability to surgical intervention make the surgical treatment of intracranial tumors challenging. We evaluated the surgical treatment of sup ratentorial tumors using intraoperative magnetic resonance imaging (MRI), w hich provides real-time guidance, allows localization of intracranial tumor s and their margins, and facilitates continuous assessment of surgical prog ress. METHODS: Sixty patients underwent craniotomies for tumor treatment in the G eneral Electric intraoperative MRI unit at the Brigham and Women's Hospital (Boston, MA) during a 1-year period, The patients selected were those with intracranial tumors that were considered difficult to resect because of th eir locations or previous incomplete operations. Twenty-nine low-grade and 19 high-grade gliomas, 8 metastatic lesions, 2 meningiomas, 1 pineoblastoma , and 1 astroblastoma were resected. RESULTS: Tumors were accurately localized and targeted, and the extent of r esection, as well as any intraoperative complications, could be immediately assessed during surgery. Marked brain shifting occurred during the procedu res, and repeated intraoperative imaging allowed surgical accommodation for this shifting, In more than one-third of the cases, intraoperative imaging showed residual tumor when resection appeared complete on the basis of sur gical observation alone. CONCLUSION: Intraoperative MRI is a revolutionary tool for the surgical tre atment of brain tumors, providing observation of the procedure as it is bei ng performed. With intraoperative MRI, tumor resection is safer, the extent of resection can be directly evaluated, and intraoperative complications c an be noted if they occur. Outcomes after resection depend on minimizing in jury to normal brain tissue and achieving maximal tumor resection. The use of intraoperative MRI directly affects these factors.