Advances in non-invasive diagnosis of uterine adenomyosis: a narrative review

Background and Objective: Adenomyosis is a benign gynaecological condition marked by the presence of endometrial tissue within the myometrium, frequently associated with dysmenorrhoea, menorrhagia, chronic pelvic pain, and infertility. While histological examination remains the diagnostic gold standard, its invasive nature underscores the importance of identifying accurate non-invasive alternatives. Timely and reliable preoperative diagnostics are essential to avoid unnecessary hysterectomies and to consider conservative treatments. Imaging modalities such as transvaginal ultrasound (TVUS) and magnetic resonance imaging (MRI) have shown potential in diagnosing adenomyosis, assessing myometrial involvement, and monitoring patients under conservative management. This narrative review aims to evaluate the diagnostic accuracy and feasibility of TVUS and MRI as non-invasive diagnostic tools for adenomyosis. Methods: A literature search was conducted on PubMed for studies published between January 2014 and September 2024. Only clinical trials comparing imaging techniques-specifically TVUS and MRI-with histological diagnosis were included. All studies were in English to ensure consistency in terminology. The focus on English-language sources may have limited the inclusion of potentially relevant research in other languages, introducing a minor risk of language bias. Given the heterogeneity of the selected studies, a formal risk of bias assessment was not performed. Key Content and Findings: Twelve eligible studies were identified. TVUS demonstrated an average sensitivity of 78.5% and specificity of 70.7%, while MRI showed a sensitivity of 64.8% and specificity of 87.5%. Specific ultrasound markers such as junctional zone (JZ) thickness (JZmax ≥8 mm), fan-shaped striations, and the "question mark" sign were associated with high specificity. In contrast, myometrial heterogeneity showed high sensitivity. Conclusions: The findings confirm TVUS as a reliable first-line diagnostic tool, particularly where histology or MRI is not readily accessible. A standardized classification system would improve diagnostic consistency, especially as emerging studies suggest correlations between imaging features and symptom severity. Younger women often present with milder, focal disease, while older patients typically exhibit diffuse forms. The integration of advanced imaging technologies with biomarkers may further enhance diagnostic precision, reduce the reliance on invasive procedures, and support fertility-preserving, patient-centred therapeutic strategies.