The Diagnostic Performance of Transvaginal Ultrasound for Posterior Compartment Endometriosis Compared to...

Background: Deep infiltrating endometriosis (DIE) frequently affects the posterior pelvic compartment, where accurate non-invasive imaging is essential for diagnosis and surgical planning. Aim: This systematic review evaluates the diagnostic performance of transvaginal ultrasound (TVUS) in detecting posterior compartment DIE, specifically rectosigmoid lesions, uterosacral ligament involvement, and pouch of Douglas obliteration. Material and Methods: A comprehensive literature search of PubMed, Scopus, and Web of Science was performed for studies published between 2015 and 2025. Eligible studies assessed the accuracy of TVUS for posterior compartment DIE using laparoscopy and histology as reference standards. Data on sensitivity, specificity, and overall diagnostic accuracy were extracted or derived. The study's quality was evaluated using the QUADAS-2 tool. Results: Thirty eligible studies were included. The mean sensitivities and specificities reported in the included studies reached 83.05% and 90.53% for rectosigmoid disease, 78.07% and 90.49% for uterosacral ligament involvement, and 79.58% and 89.75% for pouch of Douglas obliteration, respectively. Adjunctive techniques such as gel sonovaginography, rectal water contrast, or saline instillation into the pouch of Douglas were described, but their use was inconsistent. Marked heterogeneity in patient preparation, scanning protocols, and reporting limited comparability across studies. Despite this, TVUS demonstrated diagnostic performance within a similar range to that reported for MRI in prior systematic reviews, with the advantages of lower cost, accessibility, and integration into routine gynecological practice. Conclusions: TVUS is consistently reported as a reliable and cost-effective imaging modality and, in line with international guidelines, should be considered the first-line option for posterior compartment DIE, though further standardization of scanning and reporting protocols is needed to optimize reproducibility and clinical utility.