Gadolinium Is Not Necessary for Most Postoperative Pituitary Adenoma Imaging Surveillance

Introduction: The postoperative surveillance protocol for pituitary adenomas is highly physician dependent but often involves yearly magnetic resonance imaging (MRI) with gadolinium-based contrast agents (GBCAs) for the first several years, and gradually increasing intervals thereafter. In 2017, the FDA issued a warning that gadolinium, a heavy metal, is retained in patients tissues, including the brain, for years after the administration of GBCAs. Recent studies have demonstrated long-term retention of linear gadolinium agents in the dentate nucleus and globus pallidus. While the toxic effect of nephrogenic systemic fibrosis has been well documented, the relationship between gadolinium exposure and clinical neurotoxicity is currently under investigation. Patients at greatest risk are those requiring multiple lifetime doses, such as those with pituitary adenomas. We hypothesize that non-contrast MRI is adequate for postoperative surveillance of nonsecretory adenomas, and that contrast imaging may be reserved for secretory adenomas to minimize patient exposure.

Methods: A retrospective chart review was completed to evaluate the rate of recurrence for secretory and non-secretory pituitary adenomas. For those with recurrence, imaging was analyzed by two independent reviewers to determine whether contrast impacted the decision to intervene.

Results: A total of 154 patients underwent transsphenoidal resection of pituitary adenomas from 2005 to 2016. One hundred twenty-five (81.1%) were nonsecretory, of which 15 (12%) recurred at a mean of 34.1 months following initial resection. For secretory adenomas, recurrence was noted in 3 (10.3%) cases at a mean of 41.3 months postoperatively. There was no significant difference between rate of or time to recurrence for non-secretory versus secretory tumors (p = 0.549; p = 0.549). Similarly, extent of resection at initial operation did not significantly impact rate of recurrence (p = 0.194). MRI with contrast was necessary to make the clinical decision to offer additional treatments due to progression in none of the non-secretory and 1 of the secretory adenomas (p = 0.07).

Conclusion: The present study suggests that GBCAs are not necessary for postoperative imaging surveillance of non-secretory pituitary adenomas. This study is limited by its size and limited follow-up. Although clinical consequences of GBCA retention in patients with normal renal function have not yet been demonstrated, the observation is troubling and minimization of its use is likely prudent. We believe surveillance MRIs following the initial postoperative scan can be completed without contrast in patients with non-secretory adenomas and perhaps many secretory adenomas to minimize patient exposure to repeated doses of gadolinium.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
12 February 2021