2026 Poster Presentations
P223: THE MORPHOLOGY OF THE POSTERIOR PITUITARY GLAND ON INTRAOPERATIVE ULTRASOUND MAY PREDICT ITS POSTOPERATIVE MRI CHARACTERISTICS AFTER ENDOSCOPIC ENDONASAL RESECTION OF PITUITARY ADENOMAS
Ryan B Juncker1; Guilherme Finger, MD2; Mark A Damante, MD3; Kara A Parikh, MD3; Luciano M Prevedello, MD3; Daniel M Prevedello, MD3; Kyle C Wu, MD3; 1The Ohio State University College of Medicine; 2Indiana University School of Medicine; 3The Ohio State University Wexner Medical Center
Background: Pituitary adenomas are amongst the most common benign central nervous system tumors. Despite their benign nature, these lesions often require resection via an endoscopic endonasal approach (EEA) for symptomatic relief. Two of the most common associated complications are arginine vasopressin deficiency (AVPD) and syndrome of inappropriate antidiuretic hormone secretion (SIADH). Both are thought to be caused by intraoperative manipulation of, or injury to, the posterior pituitary gland (PPG), making visualization and preservation of this structure critical. Our group previously characterized the appearance of the PPG on intraoperative endoscopic endonasal ultrasound (IEUS), classifying its most common morphologies into two distinct categories: ellipse vs. crescent shaped (Figure 1). Other groups have demonstrated that the PPG bright spot on magnetic resonance imaging (MRI) is visible postoperatively in 53-60% of patients after EEA for pituitary adenoma, and that its presence/absence may correlate with postoperative AVPD/SIADH. This study aimed to determine if the morphology of the PPG on IEUS correlated with the presence/absence of the PPG bright spot on MRI after endoscopic endonasal pituitary adenoma resection.
Methods: This descriptive retrospective study included consecutive pituitary adenoma surgeries during which IEUS was utilized, the PPG was visualized, and postoperative MRI was available between 1/1/2022 – 12/31/2023. Demographic, clinical, radiological, and outcomes data were collected. The PPG was described as either hypoechoic, isoechoic, or hyperechoic as compared to the anterior pituitary gland and adenoma on each IEUS image, and its morphology was classified as ellipse or crescent-shaped. Postoperative, pre-contrast T1 MRI images were reviewed to evaluate for the presence/absence of the PPG bright spot.
Results: Twenty-eight patients were included, the majority of which were female (71.4%) and averaged 48.3 years (±15.1) years of age. On IEUS imaging, the PPG was hypoechoic compared to the anterior pituitary gland and adenoma in all 28 cases. Morphologically, the PPG appeared elliptical in 15 cases (53.6%), and crescent shaped in 13 cases (46.4%). The PPG bright spot was identified on postoperative MRI in 23 cases (82.1%). Of the 5 cases in which the PPG bright spot was not visualized, it appeared crescent-shaped on IEUS in 4 of the cases (80.0%) and ellipse-shaped only once (20.0%). New postoperative AVPD/SIADH was seen in 5/23 cases (21.7%) in which the PPG was identified on postoperative MRI, and 1/5 cases (20.0%) where it was not.
Conclusion: When identified, the morphology of the PPG on IEUS appears to correlate with the presence of the PPG bright spot on postoperative MRI, with an intraoperative ellipse-shape more often leading to the PPG being visualized postoperatively. Moreover, in this series of patients where the PPG was confirmed to be identified on IEUS, the PPG bright spot was then identified on postoperative MRI in 82% of cases, substantially more than the 53-60% previously reported. Intraoperative identification of the PPG with IEUS resulted in radiographic indications of PPG preservation postoperatively, but did not correlate with clinical outcomes in this limited population. Currently, the authors are including more patients to confirm these correlations and their clinical relevance in a larger population.
