Accuracy of transvaginal ultrasound for diagnosis of deep infiltrating endometriosis in the uterosacral ligaments: Systematic review and meta-analysis

Ultrasound of the uterosacral ligaments: A reliability study for diagnosing endometriosis in Australian non-specialised medical imaging and radiology settings

Introduction/Background

Uterosacral ligaments (USL) are the most common sites of endometriosis. Transvaginal ultrasound (TVS) demonstrates high diagnostic accuracy for endometriosis of the USLs using standardised technique and characterisations. While high accuracy and reproducibility is established with these techniques by well-trained professionals, the question still remains if these techniques are reproducible in general settings. This study aims to assess the intra and interobserver agreement of TVS characteristics of USLs, between experienced and less experienced examiners in an Australian general ultrasound imaging practice, where sonographers are required to perform ultrasound for endometriosis.

Methods

Forty-two patients, with and without known endometriosis, underwent ultrasound imaging of the USLs. Images were obtained of uterosacral ligaments and collated for interobserver survey. Six professional observers independently reviewed the images, classifying characteristics such as echogenicity, echotexture, contour, thickness, and presence of nodules. Interobserver reliability was assessed using Gwet's agreement coefficients (AC1), and the correlation between USL thickness and endometriosis was analyzed using Spearman's correlation.

Results

Interobserver agreement for detecting USL endometriosis was substantial (AC1 = 0.63), with an overall agreement of (0.65) for the seven USL characteristics. Intraobserver agreement ranged from moderate (0.60) to almost perfect (0.96). Experience did not significantly affect intraobserver reliability. A strong positive correlation was found between USL thickness and endometriosis (r = 0.7965, P < 0.01).

Conclusion

This study demonstrates high inter and intraobserver agreement among sonographers and radiologists in a general imaging department for identifying USL characteristics and diagnosing USL endometriosis. Both experienced and less experienced operators can reliably assess USLs Consistency was shown in identifying thickened uterosacral ligaments however, there is no consensus on where uterosacral ligament be measured. Even so, a thickened USL can prompt further extension of the pelvic scan to look for other endometriosis markers.

Clues to revising the conventional diagnostic algorithm for endometriosis

Endometriosis is a complex gynecologic disorder characterized primarily by symptoms of pelvic pain, infertility, and altered quality of life. National and international guidelines highlight the diagnostic difficulties and lack of conclusive diagnostic tools for endometriosis. Furthermore, guidelines are becoming questionable at an increasingly rapid rate as new diagnostic techniques emerge. This work aims to provide a knowledge synthesis of the relevance of various diagnostic tools and to assess areas of improvement of conventional algorithms. MEDLINE and Cochrane Library databases were searched from January 2021 to December 2023 using relevant key words. Articles evaluating the diagnostic relevance and performance of various tools were included and independently reviewed by the authors for eligibility. Included studies were assessed using the GRADE and QUADAS-2 tools. Of the 4204 retrieved articles, 26 were included. While anamnesis and clinical examination do contribute to diagnostic accuracy, their level of evidence and impact on the diagnostic process remains limited. Although imaging techniques are recommended to investigate endometriosis, ultrasonography remains highly operator dependent. Magnetic resonance imaging appears to exhibit higher sensitivities than ultrasound. However, concerns persist with regards to the terminology, anatomical definition of lesions, and accuracies of both ultrasound and magnetic resonance imaging. Recently, several biological markers have been studied and cumulative evidence supports the contribution of noncoding RNAs to the diagnosis of endometriosis. Marginal improvements have been suggested for anamnesis, clinical examination, and imaging examinations. Conversely, some biomarkers, including the saliva microRNA signature for endometriosis, have emerged as diagnostic tools which inspire reflection on the revision of conventional diagnostic algorithms.

Douglas Pouch Fluid Improves the Accuracy of Transvaginal Ultrasound in the Diagnosis of Uterosacral Ligaments Deep Infiltration Endometriosis: A Prospective Study

OBJECTIVES

To compare the accuracy of transvaginal ultrasound (TVUS) with laparoscopy in detecting and characterizing uterosacral ligament (USL) nodules of deep infiltrative endometriosis (DIE) between patients with and without pouch of Douglas (POD) fluid.

METHODS

This prospective study was conducted between June 2021 and July 2023. We included patients from the Second People's Hospital of Shenzhen with two TVUS tests: no POD fluid on the first TVUS test and POD fluid on the second TVUS test. POD fluid was obtained in two ways: naturally occurring fluid during the luteal phase of the menstrual cycle and SonoPODography. Laparoscopic results are the gold standard. To compare the diagnostic performance of TVUS in the diagnosis of DIE on USLs with and without POD fluid.

RESULTS

We included 42 patients with a mean age of 36.4 ± 5.4 years. The maximum length diameter for DIE nodules on USLs with and without POD fluid was 13.3 ± 3.3 mm and 10.2 ± 2.5 mm (P < .001), respectively, while the depth of infiltration was 8.1 ± 2.4 mm and 6.1 ± 1.4 mm (P < .001), respectively. When compared to laparoscopic findings, TVUS findings with and without POD fluid resulted in a sensitivity, specificity, accuracy, positive predictive value, negative predictive value area under the curve, and Cohen kappa of 92.3%, 93.8%, 92.9%, 96.0%, 88.2%, 0.930, and 0.850 and 61.5%, 93.8%, 73.8%, 94.1%, 50.0%, 0.766, and 0.499, respectively. Laparoscopy showed USL involvement in up to 59.5% of patients. With or without fluid, the most common ultrasound features of DIE lesions were USL thickening, irregular morphology, clear boundaries, low echo, and no blood flow signal.

CONCLUSIONS

For patients with clinical suspicion of DIE, TVUS with POD fluid has a higher accuracy for diagnosing USL DIE than TVUS without POD fluid.

Relationship Between Ultrasound Diagnosis, Symptoms and Pain Scale Score on Examination in Patients with Uterosacral Ligament Endometriosis

Background/Objectives: This study investigated patient pain descriptors for transvaginal ultrasound (TVS) diagnostic evaluation of endometriosis for uterosacral ligaments (USLs), including correlation between USL thickness and site-specific tenderness (SST). It further investigated if SST could positively assist diagnosing endometriosis on TVS. Methods: TVS images and SST pain descriptors were collected from 42 patients. SST was evaluated by applying sonopalpation during TVS. The images were presented to six observers for diagnosis based on established USL criteria. Following this, they were given the SST pain scores and asked to reevaluate their diagnosis to assess if the pain scores impacted their decision. Results: An independent t-test showed that the patients with an endometriosis history had higher pain scores overall (7.2 ± 0.59) compared to the patients with no history (0.34 ± 0.12), t (40) = 8.8673. Spearman's correlation showed a strong correlation to the pain scale score for clinical symptoms (r = 0.74), endometriosis diagnosis (r = 0.78), USL thickness (r = 0.74), and when USL nodules were identified (r = 0.70). Paired t-tests showed that the observers demonstrated a higher ability to correctly identify endometriosis with the pain scale information (33 ± 8.83) as opposed to not having this information (29.67 ± 6.31), which was a statistically significant change of 3.33, t (5) = 2.7735. Conclusions: Patients with an endometriosis history have significantly higher pain scores on TVS compared to patients with no endometriosis history. A strong correlation was shown between SST pain scores and patient symptoms, USL thickness, and USL nodules. Inclusion of SST alongside TVS imaging shows promise, with these results demonstrating a higher ability to diagnose endometriosis with additional SST pain scale information.

Radiology State-of-the-art Review: Endometriosis Imaging Interpretation and Reporting

Endometriosis is a common condition impacting approximately 190 million individuals and up to 50% of women with infertility globally. The disease is characterized by endometrial-like tissue located outside of the uterine corpus, which causes cyclical hemorrhage, inflammation, and fibrosis. Based on clinical suspicion or findings at routine transvaginal pelvic US or other prior imaging, dedicated imaging for endometriosis may be warranted with MRI or advanced transvaginal US. Deep endometriosis (DE) in the pelvis includes evaluation for stromal and fibrotic components and architectural distortion resulting from fibrosis and tethering. It is a disease requiring a compartment-based, pattern-recognition approach. MRI has the benefit of global assessment of the pelvis and is effective in assessing for features of malignancy and for evaluating extrapelvic locations. Transvaginal US has the advantage of dynamic maneuvers to assess for adhesions and may achieve higher spatial resolution for assessing the depth of bowel wall invasion. T1-weighted MRI evaluation increases the specificity of diagnosis by identifying hemorrhagic components, but the presence of T1 signal hyperintensity is not essential for diagnosing DE. Endometriosis is a disease with a broad spectrum; understanding the mild through advanced manifestations, including malignancy evaluation, is within the scope and breadth of radiologists' interpretation.

Society of Radiologists in Ultrasound Consensus on Routine Pelvic US for Endometriosis

Endometriosis is a prevalent and potentially debilitating condition that mostly affects individuals of reproductive age, and often has a substantial diagnostic delay. US is usually the first-line imaging modality used when patients report chronic pelvic pain or have issues of infertility, both common symptoms of endometriosis. Other than the visualization of an endometrioma, sonologists frequently do not appreciate endometriosis on routine transvaginal US images. Given a substantial body of literature describing techniques to depict endometriosis at US, the Society of Radiologists in Ultrasound convened a multidisciplinary panel of experts to make recommendations aimed at improving the screening process for endometriosis. The panel was composed of experts in the imaging and management of endometriosis, including radiologists, sonographers, gynecologists, reproductive endocrinologists, and minimally invasive gynecologic surgeons. A comprehensive literature review combined with a modified Delphi technique achieved a consensus. This statement defines the targeted screening population, describes techniques for augmenting pelvic US, establishes direct and indirect observations for endometriosis at US, creates an observational grading and reporting system, and makes recommendations for additional imaging and patient management. The panel recommends transvaginal US of the posterior compartment, observation of the relative positioning of the uterus and ovaries, and the uterine sliding sign maneuver to improve the detection of endometriosis. These additional techniques can be performed in 5 minutes or less and could ultimately decrease the delay of an endometriosis diagnosis in at-risk patients.

Nonsurgical approaches to the diagnosis and evaluation of endometriosis

An inability to make the diagnosis of endometriosis or evaluate lesion response to treatment without surgery is a clear impediment to understanding the disease and to developing new therapies. The need is particularly strong for rASRM Stage 1 or 2 disease, since higher stage (rASRM Stage 3 or 4) endometriosis can often be diagnosed by ultrasound or other imaging techniques. Despite promising findings in association studies, no biomarkers or nonsurgical diagnostic or evaluation methods for Stage 1 or Stage 2 endometriosis has yet been clinically validated. Admittedly, validation is difficult, since surgery is required as a gold standard diagnostic method for comparison. This manuscript is aimed as a succinct review of what is known about nonsurgical approaches to detect and assess endometriosis, with an emphasis on Stage 1 and 2.

Ultrasound Characteristics and Scanning Techniques of Uterosacral Ligaments for the Diagnosis of Endometriosis: A Systematic Review

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.

Diagnostic Accuracy of Transvaginal Sonography for Deeply Infiltrating Endometriosis and Pouch of Douglas Obliteration in the Presence or Absence of Ovarian Endometrioma

Background: Endometriosis is one of the most common gynecological diseases worldwide. Significant attention has been drawn to this multiorgan and often painful disorder. Objectives: This study aimed to examine the accuracy of transvaginal sonography (TVS) in the diagnosis of deeply infiltrating endometriosis (DIE) with respect to the presence or absence of ovarian endometrioma (OE). Patients and Methods: This cross-sectional study was performed on all patients undergoing TVS before gynecological laparoscopy. With pathological confirmation as the standard reference, the diagnostic accuracy of TVS for DIE and pouch of Douglas (POD) obliteration was compared with that of laparoscopy in the anterior and posterior pelvic compartments with respect to the presence or absence of OE. Agreement between TVS and laparoscopy was evaluated for each case, and Cohen’s kappa statistic was measured for each site of involvement. Moreover, sensitivity, specificity, negative and positive predictive values, and likelihood ratios of TVS were calculated, with laparoscopy as the reference test. Results: A total of 110 patients, with a mean age of 37.20 ± 7.16 years, were recruited in this study. The accuracy, sensitivity, and negative predictive value of TVS for the diagnosis of DIE and POD obliteration were estimated at 89.5%, 58.3%, and 88.9% in the anterior pelvic compartment and 93.3%, 92%, and 70.6% in the posterior pelvic compartment, respectively. Nevertheless, TVS showed lower sensitivity for detecting pelvic adhesions and peritoneal cysts compared to laparoscopy. The presence of OE did not significantly increase the accuracy of TVS for the diagnosis of DIE or POD obliteration (P > 0.05). Conclusion: The present study showed that TVS is an adequately accurate and non-invasive diagnostic tool for the detection and mapping of DIE and POD obliteration, regardless of the presence of OE. TVS may waive the need for exploratory laparoscopy in DIE or at least facilitate precise pre-procedural DIE mapping.

Endometriosis: A multimodal imaging review

Endometriosis is a chronic inflammatory disorder characterized endometrial-like tissue present outside of the uterus, affecting approximately 10% of reproductive age women. It is associated with abdomino-pelvic pain, infertility and other non - gynecologic symptoms, making it a challenging diagnosis. Several guidelines have been developed by different international societies to diagnose and classify endometriosis, yet areas of controversy and uncertainty remains. Transvaginal ultrasound (TV-US) is the first-line imaging modality used to identify endometriosis due to its accessibility and cost-efficacy. Enhanced sonographic techniques are emerging as a dedicated technique to evaluate deep infiltrating endometriosis (DIE), depending on the expertise of the sonographer as well as the location of the lesions. MRI is an ideal complementary modality to ultrasonography for pre-operative planning as it allows for a larger field-of-view when required and it has high levels of reproducibility and tolerability. Typically, endometriotic lesions appear hypoechoic on ultrasonography. On MRI, classical features include DIE T2 hypointensity, endometrioma T2 hypointensity and T1 hyperintensity, while superficial peritoneal endometriosis (SPE) is described as a small focus of T1 hyperintensity. Imaging has become a critical tool in the diagnosis, surveillance and surgical planning of endometriosis. This literature review is based mostly on studies from the last two decades and aims to provide a detailed overview of the imaging features of endometriosis as well as the advances and usefulness of different imaging modalities for this condition.

What is the accuracy of transvaginal ultrasound for endometriosis mapping prior to surgery when performed by a sonographer within an outpatient women's imaging centre?

INTRODUCTION

This study aimed to assess the accuracy of transvaginal ultrasound (TVUS) for the mapping of endometriosis before surgery when performed by sonographers in an outpatient women's imaging centre.

METHODS

A prospective longitudinal cohort study was performed. The study group comprised of 201 women who underwent a comprehensive TVUS assessment, performed by a sonographer. Laparoscopy was performed as the reference standard. Complete TVUS and surgical data were available for 53 women who were included in the final analysis.

RESULTS

Endometriosis was confirmed at a surgery in 50/53 (94.3%) participants, with 25/53 (47.2%) having deep endometriosis (DE) nodules and/or endometriomas present. TVUS for mapping of DE had an overall sensitivity of 84.0%, specificity of 89.3%, PPV of 87.5%, NPV of 86.2%, LR+ of 7.85, LR- of 0.18, and accuracy of 86.8% (P < 0.001). Ovarian immobility had poor sensitivity for detecting localised superficial endometriosis, DE, adhesions, and/or endometriomas (Left = 61.9% and right = 13.3%) but high specificities (left = 87.5% and right = 94.7%). Site-specific tenderness had low sensitivities and moderate specificities for the same. All soft markers of endometriosis failed to reach statistical significance except for left ovarian immobility (P = <0.001).

CONCLUSION

Sonographers well experienced in obstetric and gynaecological imaging, working in an outpatient women's imaging setting can accurately map DE; however, the performance of soft markers for detection of SE was poor.