Intraoperative magnetic resonance imaging assessment of non-functioning pituitary adenomas during transsphenoidal surgery

Purpose: To review the utility of intraoperative imaging in facilitating maximal resection of non-functioning pituitary adenomas (NFAs). Methods: We performed an exhaustive MEDLINE search, which yielded 5598 articles. Upon careful review of these studies, 31 were pertinent to the issue of interest. Results: Nine studies examined whether intraoperative MRI (iMRI) findings correlated with the presence of residual tumor on MRI taken 3 months after surgical resection. All studies using iMRI of >0.15T showed a ≥90 % concordance between iMRI and 3-month post-operative MRI findings. 24 studies (22 iMRI and 2 intraoperative CT) examined whether intraoperative imaging improved the surgeon’s ability to achieve a more complete resection. The resections were carried out under microscopic magnification in 17 studies and under endoscopic visualization in 7 studies. All studies support the value of intraoperative imaging in this regard, with improved resection in 15–83 % of patients. Two studies examined whether iMRI (≥0.3T) improved visualization of residual NFA when compared to endoscopic visualization. Both studies demonstrated the value of iMRI in this regard, particularly when the tumor is located lateral of the sella, in the cavernous sinus, and in the suprasellar space. Conclusion: The currently available literature supports the utility of intraoperative imaging in facilitating increased NFA resection, without compromising safety.