Deep endometriosis: evaluation of ENZIAN and #ENZIAN classification systems by MRI compared with surgery—a meta-analysis

Objective To assess the reproducibility and the diagnostic accuracy of MRI for the assessment of (#)ENZIAN classification in patients with deep endometriosis by means of a meta-analysis.

MEDLINE and EMBASE databases were searched for relevant articles from January 1, 2005, to January 1, 2025. Data on MRI reproducibility (interobserver/intraobserver kappa) were extracted for P (peritoneum), O (ovary), T (tubo-ovarian condition), A (vagina/rectovaginal space), B (utero-sacral ligaments), C (rectum/sigmoid colon), FA (F adenomyosis), FB (F bladder), FU (F ureter), FI (F intestinum), and FO (F other). Pooled sensitivity, specificity, PPV, and NPV were calculated for each compartment.

Twelve articles (1024 patients) were included, of which 7 used ENZIAN and 5 used #ENZIAN. MRI-based (#)ENZIAN showed high reliability for O, A, B, and C, with substantial or excellent agreement in most studies. MRI-based (#)ENZIAN showed high diagnostic values for O, T, A, B, and C. Sensitivity and specificity for O were 97.5% and 96.4% and for T, 94.1% and 89.1%, respectively. Sensitivity values for A, B, and C were slightly lower, but remained high at 76.1%, 83.4%, and 79.1% respectively, and specificity values were high at 92.4%, 87.8%, and 94.8%. Sensitivity values for FA, FB, and FI were low, with values of 64.6%, 56.9%, and 66.8%. Data for P, FU, and FO were insufficient and could not be pooled.

MRI-based (#)ENZIAN showed high reliability for compartments O, T, A, B, and C. Data for other compartments were either insufficient or the diagnostic accuracy was low. Key Points Question What is the diagnostic value of MRI in the assessment of (#) ENZIAN classification in patients with deep endometriosis? Findings MRI-based(#)ENZIAN showed high diagnostic values for compartments O, T, A, B, and C. Data on the remaining compartments were insufficient, or the diagnostic accuracy was low. Clinical relevance MRI-based (#) ENZIAN can be used for assessing endometriosis located at the ovaries, tubal ovarian condition, vaginal-rectovaginal space, utero-sacral ligaments, and rectosigmoid. For other compartments, more data are needed and clear definitions might also improve the role of MRI. Graphical Abstract Similar content being viewed by others Abbreviations - DE: - Deep endometriosis - MRI: - Magnetic resonance imaging - NPV: - Negative predictive value - PPV: - Positive predictive value - QUADAS-2: - Quality assessment of diagnostic accuracy studies 2

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Author information Authors and Affiliations Corresponding author Ethics declarations Guarantor The scientific guarantor of this publication is Shandra Bipat. Conflict of interest The authors of this manuscript declare no relationships with any companies, whose products or services may be related to the subject matter of the article. Statistics and biometry One of the authors has significant statistical expertise. Informed consent Not applicable. This study concerns a meta-analysis. Ethical approval Institutional Review Board approval was not required because the study concerns a meta-analysis. Methodology - This study concerns a meta-analysis and was performed according to the Cochrane Handbook for Systematic Reviews of Diagnostic Test Accuracy and is reported following the PRISMA guideline (preferred reporting items for systematic reviews and meta-analyses statement) Additional information Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Supplementary information Rights and permissions Springer 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. About this article Cite this article Mohamed, Y., Kol, S.Q., Stoker, J. et al. Deep endometriosis: evaluation of ENZIAN and #ENZIAN classification systems by MRI compared with surgery—a meta-analysis. Eur Radiol 36, 4489–4502 (2026). https://doi.org/10.1007/s00330-025-12154-3 Received: Revised: Accepted: Published: Version of record: Issue date: DOI: https://doi.org/10.1007/s00330-025-12154-3