Transsphenoidal Resection of Pituitary Adenomas in an Intraoperative MRI Unit

Background: Transsphenoidal resection is a well known surgical procedure used in the treatment of sellar and parasellar lesions. In certain cases, operative identification of the lesion and achieving a complete resection can be problematic. We describe a surgical image guidance method using an intraoperative MRI which provides definitive identification of a lesion and verification of a complete resection. Material and Methods: Five patients with pituitary macroadenomas underwent transsphenoidal resection of their tumors in the intraoperative MRI unit at the Brigham and Women's Hospital. This unit was developed as a collaboration between General Electric and BWH and is an open configuration o.5 Tesla MR imager in which surgery can be performed with real time, intraoperative MR guidance. Results: The transsphenoidal resections were performed in a standard fashion in this unit. Intraoperative imaging allowed accurate localization of the lesions, identification of pertinent surrounding structures, and the evaluation of the extent of each resection. In two patients, the resection would have been considered complete based on the surgical field of view alone but MR imaging allowed remaining tissue to be identified. Developing clot was seen in one patient after a fat graft had been placed. Conclusion: The intraoperative MR is a surgical modality by which transsphenoidal resection of pituitary macroadenomas can be performed using real-time image guidance. It allows definitive identification of the tumor and an immediate evaluation of whether resection is complete. It also can monitor the occurrence of intraoperative complications such as hemorrhage. This revolutionary device can be an important tool for the surgical management of pituitary tumors.