Ultrasound Characteristics and Scanning Techniques of Uterosacral Ligaments for the Diagnosis of Endometriosis

Abstract

Endometriosis is a common and painful gynaecological condition that takes an average of 6.4years to diagnose. While laparoscopic surgery is the recommend gold standard in diagnosis of endometriosis, transvaginal ultrasound (TVS) is able to assist surgeons in the planning and management of patients, especially when there is limited visualisation in the posterior compartment. Uterosacral ligaments (USL) are located in the posterior compartment and are one of the first and most common places that endometriosis deposits, The International Deep Endometriosis Analysis (IDEA) group consensus, which are the current guidelines for DE imaging, recommends a thorough ultrasound assessment to identify endometriotic disease. This includes an assessment of anatomic structures in the posterior compartment including the USLs. However, IDEA does not explicitly articulate specifics of USL imaging and measurements on ultrasound. The primary aim of this review is to determine is to identify ultrasound techniques and characteristics of USLs in the diagnosis of deep infiltrative endometriosis (DE). The secondary aim is to describe and summarise these findings into normal and pathological findings. A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines. A population, interventions, comparator, and outcome framework was used to define a search strategy. Articles were screened using Covidence review management system, and data was extracted by two authors using a standardised and piolet‐tested form. Quality assessment was conducted using the Critical Appraisal Skills Programme (CASP). Medline, Embase and Scopus and Google Scholar were searched yielding 250 articles, with 22 being included in the review. Analysis of the data demonstrated inconsistent reporting of ultrasound techniques and characteristics of USLs. Most (20/22) papers described abnormal criteria of USLs, only 5/22 papers determined what the normal USL appearance is or what techniques (11/22) were applied. Even though reporting was heterogeneous, there was a high level of tertiary centre participation with gynaecological experienced operators, therefore was a high level of agreement. Through review of the current literature, this study has investigated ultrasound techniques and characteristics of USLs for the diagnosis of DE. All papers included in this review reported presence of pathological sonographic findings of the USLs when DE was presented therefore it is recommended that USL examination become a part of TVS exams when DE is clinically suspected. This study also demonstrated that there was lack of data and no agreement when it comes to measuring USLs with DE. Even so, the current evidence demonstrates that scanning the USLs, and locating, identifying, and describing USL thickening and endometriotic nodules in the various locations using the described techniques and characteristics in this review has clinical value in early diagnosis.

Prospective diagnostic test accuracy of transvaginal ultrasound posterior approach for uterosacral ligament and torus uterinus deep endometriosis

“…in 2020. Our findings suggest that identifying DE in its most common location, the USLs, with the TVS probe placed within the posterior vaginal fornix, may yield improved diagnostic accuracy relative to that reported in the literature 11,12 . When assessing diagnostic performance, our findings suggest variations according to anatomical site and reference test; however, these were subtle, as indicated by the large overlap in 95% CI.…”

“…There is a ubiquitous acceptance of the need for USL evaluation as part of TVS examination for endometriosis 11 . Although the USL is the most common location of DE, it remains the most difficult to diagnose due to the small size of nodules and lack of experience of clinicians in evaluating these structures using imaging [10][11][12] .…”

“…There is a ubiquitous acceptance of the need for USL evaluation as part of TVS examination for endometriosis 11 . Although the USL is the most common location of DE, it remains the most difficult to diagnose due to the small size of nodules and lack of experience of clinicians in evaluating these structures using imaging [10][11][12] . Despite recent advancements made through the development of the IDEA consensus to aid the diagnosis of endometriosis, the diagnostic test performance of TVS for DE in these anatomical areas has not improved 9,11 .…”

“…Although the USL is the most common location of DE, it remains the most difficult to diagnose due to the small size of nodules and lack of experience of clinicians in evaluating these structures using imaging [10][11][12] . Despite recent advancements made through the development of the IDEA consensus to aid the diagnosis of endometriosis, the diagnostic test performance of TVS for DE in these anatomical areas has not improved 9,11 . A recent study evaluating the diagnostic performance of TVS using the IDEA consensus among all anatomical sites suggested that the accuracy was lowest for the right and left USLs and TU, with accuracy ranging between 65.2% to 74.4%, sensitivity ranging between 44.2% and 58.7% and specificity ranging between 77.8% and 88.2% for the three sites 9 .…”

“…Despite these recent developments, diagnosis of DE of the USLs remains the most difficult, exhibiting only moderate accuracy 10 , including a sensitivity of 60-67% and specificity of 86-95% 11,12 , even though the USL is the most common location of DE 10,13 . Several research groups have argued that TVS methodology to visualize normal and abnormal USLs and TU is limited, yielding poor diagnostic test accuracy values 11,14 .…”