Design: This is a retrospective review of patients who underwent surgical management for endometriosis staged intraoperatively with the 2021 AAGL Endometriosis Classification. Pre- operative magnetic resonance imaging (MRI) of pelvis was performed and images were independently reviewed by two academic radiology fellows specializing in abdominal imaging. Endometriosis stage calculated by each physician were assessed with kappa statistics to identify variations in inter-reader reliability and ultimately impact on surgical planning.

Setting: Single academic institution

Patients or Participants: A total of 79 charts were reviewed of patients who underwent surgical management for pre-operative concern of endometriosis by a single gynecologic surgeon between November 2021 and April 2023. Of these charts, 35 patients had both pre-operative MRIs performed and intraoperative endometriosis staging based on the 2021 AAGL Endometriosis classification.

Interventions: N/A

Measurements and Main Results: Of the 35 patients, 16 (46%) patients had unanimous classification agreement between two readers and intraoperative staging, with 15 patients having stage IV endometriosis. 11 (31%) patients had one reader classification agreement with intraoperative staging. The sensitivities of detecting endometriosis from readers 1 and 2 were 77% and 94% respectively. Discrepancies between readers and positive operative findings with significant impact on surgical planning, including obliterated cul-de-sac and deep infiltrative endometriosis in the urologic or GI tract, were noted in 9 (26%) cases. Revised inter-reader reliability data will be presented.

Conclusion: There exists some limitations in feasibility and reproducibility when applying the AAGL Endometriosis Classification system to pre operative MRI. Continued use of the AAGL Endometriosis Classification intraoperatively may help optimize standardization and accuracy of MRI reporting among radiology specialists.