{"paper_id":"824f321a-c254-48e1-aa3e-3586d5727b7d","body_text":"Abstract\nPurpose\nPelvic MRI is increasingly performed as a second-line investigation in suspected complex cases of endometriosis, to precisely localize lesions and to optimise surgical planning. To facilitate MRI evaluation and inter-disciplinary communication, several standardized structured image analysis and radiologic reporting classification systems have been proposed, including the mr#ENZIAN classification, whose applicability needs further proving.\nMaterials and methods\nIn an attempt to further validate the #ENZIAN classification applicability to MRI, we retrospectively evaluated the results of structured and unstructured MRI analysis by #ENZIAN compartment, considering both sole lesion-detection and #ENZIAN grading, using the corresponding op#ENZIAN score as a reference and evaluating inter-rater agreement of structured mr#ENZIAN results. In total, 83 patients with surgically/histopathologically confirmed endometriosis who received a pelvic MRI within 8 months prior to surgery between 2018 and 2022 were included.\nResults\nConcordance of mr#ENZIAN and op#ENZIAN results proved to be highly dependent on #ENZIAN-compartment: almost perfect agreement in locations FU, FI and others (FO); substantial agreement for lesion detection and grading in O, C and P; moderate to substantial agreement in T; moderate agreement in FB; moderate to fair agreement in A and only fair to poor agreement in B and FA. Inter-rater agreement between expert radiologists proved to be almost perfect to substantial for lesion detection and grading in most compartments, with exception of A, B and FA. There were no significant differences between results of structured and unstructured MRI evaluation.\nConclusion\nWe recommend a simplification of the mr#ENZIAN classification regarding DE, with clearer rules to differentiate and measure lesions affecting the A and B compartments.\nSimilar content being viewed by others\nData availability\nAll data supporting the findings of this study are available within the paper.\nAbbreviations\n- AC1:\n-\nGwet’s AC1 coefficient\n- CI:\n-\nConfidence intervals\n- DE:\n-\nDeep endometriosis\n- ESUR:\n-\nEuropean society of urogenital radiology\n- NPA:\n-\nNegative percent agreement\n- PPA:\n-\nPositive percent agreement\n- R1:\n-\nRater 1\n- R2:\n-\nRater 2\n- SOP:\n-\nStandard operating procedure\n- TVUS:\n-\nTransvaginal ultrasound\nReferences\nGiudice LC, Kao LC (2004) Endometriosis. 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Insights Imaging 14:120. https://doi.org/10.1186/s13244-023-01466-x\nAuthor information\nAuthors and Affiliations\nContributions\nD.MH.: Conceptualisation, Methodology, Investigation, Writing - Original Draft & Editing, Visualisation; C.K.: Formal analysis, Writing - Review & Editing; E. JC.: Investigation; M.P.: Investigation; P.S.: Investigation; B.S.: Conceptualisation, Writing - Review & Editing; B.H.: Conceptualisation, Methodology, Investigation, Writing - Review & Editing, Supervision.\nCorresponding author\nEthics declarations\nCompeting interests\nThe authors declare no competing interests.\nEthical approval\nThis retrospective study was approved by the local institutional review board (Medical University of Innsbruck, protocol-number: EK1298/2024) waiving the need for patient informed consent.\nAdditional information\nPublisher’s note\nSpringer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.\nRights and permissions\nSpringer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.\nAbout this article\nCite this article\nMorell-Hofert, D., Kremser, C., Josip-Caleta, E. et al. Retrospective evaluation of the mr#ENZIAN classification’s applicability in the pre-operative assessment of complex endometriosis: a compartment-dependent challenge. Abdom Radiol (2026). https://doi.org/10.1007/s00261-026-05445-w\nReceived:\nRevised:\nAccepted:\nPublished:\nVersion of record:\nDOI: https://doi.org/10.1007/s00261-026-05445-w","source_license":"public-domain-us","license_restricted":false}