Ultrasound diagnosis of bowel endometriosis

: Background Bowel endometriosis is one of the more severe manifestations of deep endometriosis; it may cause pain and intestinal symptoms. The non-invasive diagnosis of bowel endometriosis is of crucial importance in planning the management of patients affected by this condition. Objectives This review aims to describe how transvaginal ultrasonography (TVS) is performed in patients with suspicion of rectosigmoid endometriosis, the diagnostic performance, and the strengths and limitations of this technique. Methods To identify relevant literature, a literature search was performed across the PubMed and Google Scholar databases up to July 2024. Outcome Numerous meta-analyses have demonstrated that TVS has high diagnostic accuracy in diagnosing rectosigmoid endometriosis. Rectosigmoid nodules can present with different morphological characteristics, but they are typically described as irregular, hypoechoic nodules located in the anterior wall of the rectosigmoid colon. The presence of "soft markers," such as a negative sliding sign and kissing ovaries, can further reinforce the diagnosis of this condition. Postero-lateral parametrial involvement often coexists with large rectal nodules. Introducing water contrast into the rectosigmoid does not improve the performance of TVS in diagnosing rectosigmoid endometriosis. Conclusions and Outlook TVS should be the first-line investigation in women suspected of having rectosigmoid endometriosis. The widespread use of TVS for the diagnosis of intestinal endometriosis can reduce diagnostic delays and facilitate the treatment of patients affected by this condition.