Meta-analysis and systematic review to determine the optimal imaging modality for the detection of uterosacral ligaments/torus uterinus, rectovaginal septum and vaginal deep endometriosis.

Study Question: Is there an ideal imaging modality for the detection of uterosacral ligaments/torus uterinus (USL), rectovaginal septum (RVS) and vaginal deep endometriosis (DE) in women with a clinical history of endometriosis?

Summary Answer: The sensitivity for the detection of USL, RVS and vaginal DE using MRI seems to be better than transvaginal ultrasonography (TVS), whilst the specificity of both were excellent.

What Is Known Already: The surgical management of women with DE can be complex and requires advanced laparoscopic skills with maximal cytoreduction being vital at the first procedure to provide the greatest symptomatic benefit. Owing to a correlation of TVS findings with surgical findings, preoperative imaging has been used to adequately consent women and plan the appropriate surgery. However, until publication of the consensus statement by the International Deep Endometriosis Analysis Group in 2016, there were significant variations within the terms and definitions used to describe DE in the pelvis.

Study Design Size Duration: A systematic review and meta-analysis was conducted using Embase, Google Scholar, Medline, PubMed and Scopus to identify studies published from inception to May 2020, of which only those from 2010 were included owing to the increased proficiency of the sonographers and advancements in technology.

Participants/materials Setting Methods: All prospective studies that preoperatively assessed any imaging modality for the detection of DE in the USL, RVS and vagina and correlated with the reference standard of surgical data were considered eligible. Study eligibility was restricted to those including a minimum of 10 unaffected and 10 affected participants.

Main Results And The Role Of Chance: There were 1977 references identified from which 10 studies (n = 1188) were included in the final analysis. For the detection of USL DE, the overall pooled sensitivity and specificity for all TVS techniques were 60% (95% CI 32-82%) and 95% (95% CI 90-98%), respectively, and for all MRI techniques were 81% (95% CI 66-90%) and 83% (95% CI 62-94%), respectively. For the detection of RVS DE, the overall pooled sensitivity and specificity for all TVS techniques were 57% (95% CI 30-80%) and 100% (95% CI 92-100%), respectively. For the detection of vaginal DE, the overall pooled sensitivity and specificity for all TVS techniques were 52% (95% CI 29-74%) and 98% (95% CI 95-99%), respectively, and for all MRI techniques were 64% (95% CI 40-83%) and 98% (96% CI 93-99%). Pooled analyses were not possible for other imaging modalities.

Limitations Reasons For Caution: There was a low quality of evidence given the high risk of bias and heterogeneity in the included studies. There are also potential biases secondary to the risk of misdiagnosis at surgery owing to a lack of either histopathological findings or expertise, coupled with the surgeons not being blinded. Furthermore, the varying surgical experience and the lack of clarity regarding complete surgical clearance, thereby also contributing to the lack of histopathology, could also explain the wide range of pre-test probability of disease.

Wider Implications Of The Findings: MRI outperformed TVS for the per-operative diagnosis of USL, RVS and vaginal DE with higher sensitivities, although the specificities for both were excellent. There were improved results with other imaging modalities, such as rectal endoscopy-sonography, as well as the addition of bowel preparation or ultrasound gel to either TVS or MRI, although these are based on individual studies.

Study Funding/competing Interests: No funding was received for this study. M.L. reports personal fees from GE Healthcare, grants from the Australian Women's and Children's Foundation, outside the submitted work. B.W.M. reports grants from NHMRC, outside the submitted work. G.C. reports personal fees from GE Healthcare, outside the submitted work; and is on the Endometriosis Advisory Board for Roche Diagnostics.

Registration Number: Prospective registration with PROSPERO (CRD42017059872) was obtained.