Intraoperative magnetic resonance imaging for assessment of chiasmatic decompression and tumor resection during transsphenoidal pituitary surgery

The transsphenoidal approach is the standard technique for removal of pituitary macroadenomas, but limitations in visualization of all portions of the tumor and surrounding structures can preclude complete removal of all lesions. Described here is a technique of intraoperative magnetic resonance imaging that uses standard surgical instruments and a commercially available open magnet to identify residual tumor and document decompression of the optic apparatus. This technique can increase the safety and efficacy of transsphenoidal removal of selected macroadenomas with suprasellar extension without a significant increase in operative time or cost.