Gadolinium-Based Contrast Agents in the Follow-up of Pituitary Adenomas Following Transsphenoidal Surgery: Are...

Patients with pituitary adenomas frequently undergo repeated contrast-enhanced MRIs after transsphenoidal surgery. However, the incremental diagnostic value of contrast-enhanced sequences beyond the immediate postoperative period and outside of their established role in radiation planning remains uncertain. This study evaluates whether contrast-enhanced MRI provides additional diagnostic information compared with non-contrast MRI in patients undergoing surveillance or requiring secondary intervention beyond the immediate postoperative period.

This retrospective single-center study included adult patients who underwent transsphenoidal surgery for pituitary adenomas between 2008 and 2023 and had at least two postoperative MRIs. The immediate postoperative scan was defined as the baseline scan, and the most recent available scan or the last scan before secondary intervention (repeat surgery or delayed radiation) was defined as the follow-up scan. Three readers independently reviewed each examination using non-contrast sequences alone and, at a separate session, using combined non-contrast and contrast-enhanced sequences. Tumor volume, optic pathway mass effect (3-point scale: no contact, contact without displacement, displacement), and cavernous sinus invasion (Knosp grade: 0-4) were assessed. Inter-reader reliability was evaluated using intraclass correlation coefficients (ICC) for tumor volume and weighted kappa statistics for categorical variables. Analyses were performed for the full cohort and for the subgroup undergoing secondary intervention.

91 patients were included and 42 (46%) underwent secondary intervention. Tumor volume measurements demonstrated excellent inter-reader reliability for both non-contrast and contrast-enhanced MRIs (ICC = 0.90-0.97), with no differences in measured tumor volumes for two of three readers. At baseline, agreement for optic pathway assessment was lower with contrast imaging, whereas agreement at follow-up was similar between imaging approaches. Agreement for Knosp grading was comparable between non-contrast and contrast-enhanced MRI at both baseline and follow-up. In the secondary-intervention subgroup, agreement for optic pathway assessment and Knosp grading was similar between imaging approaches at baseline and follow-up.

In the studied patient group who underwent postoperative surveillance after transsphenoidal surgery for pituitary adenomas, non-contrast MRI provided assessment of tumor volume, optic pathway mass effect and cavernous sinus invasion which was broadly similar to that obtained with contrast-enhanced MRI.