Sonovaginography: redefining the concept of a "normal pelvis" on transvaginal ultrasound pre-laparoscopic intervention for suspected endometriosis

Advances in Imaging for Assessing Pelvic Endometriosis

In recent years, due to the development of standardized diagnostic protocols associated with an improvement in the associated technology, the diagnosis of pelvic endometriosis using imaging is becoming a reality. In particular, transvaginal ultrasound and magnetic resonance are today the two imaging techniques that can accurately identify the majority of the phenotypes of endometriosis. This review focuses not only on these most common imaging modalities but also on some additional radiological techniques that were proposed for rectosigmoid colon endometriosis, such as double-contrast barium enema, rectal endoscopic ultrasonography, multidetector computed tomography enema, computed tomography colonography and positron emission tomography-computed tomography with 16α-[18F]fluoro-17β-estradiol.

How long does a transvaginal ultrasound examination for endometriosis take in comparison to a routine transvaginal ultrasound examination?

INTRODUCTION

This study aimed to determine the additional time needed to perform an endometriosis transvaginal ultrasound (eTVUS) compared to routine transvaginal ultrasound (rTVUS).

METHODS

A retrospective case-control study was performed. The study group included 199 eTVUS performed between September 2019 and September 2020. The control group comprised 105 consecutive rTVUS studies performed in the same time period. The time stamps on the ultrasound images of all cases in both groups were reviewed to determine the time taken to perform each study. Mean, median, minimum and maximum scan times for both groups were calculated as was percentage difference between scan times. A two-tailed, unpaired t-test of the normalised data and a Mann-Whitney U test assessing time difference of scans between two groups were performed with P value <0.05 considered statistically significant.

RESULTS

Performing eTVUS took significantly longer than rTVUS with increases in the mean (8.4 vs 13.8 min, 64%), median (7 vs 12 min, 71%), minimum (4 vs 7 min, 75%) and maximum (19 vs 42 min, 121%) scan times. The Mann-Whitney U test indicated a statistically significant difference in the median scan times (5.0, CI 4.0-6.0), P < 0.001. An independent t-test of the normalised data revealed a significantly larger mean scan time for eTVUS than rTVUS, Mean = 9.05 95%CI [13.17-4.94], t(302) = 4.327, P < 0.001. R 2 = 0.583.

CONCLUSION

Endometriosis transvaginal ultrasound added an average 5.4 min to rTVUS, which is statistically significant. For ultrasound departments wanting to offer this technique, doubling the scan time allocated to perform a transvaginal ultrasound (TVUS) is suggested.

Negative Sliding Sign during Dynamic Ultrasonography Predicts Low Endometriosis Fertility Index at Laparoscopy

STUDY OBJECTIVE

Endometriosis fertility index (EFI) is a robust tool to predict the pregnancy rate in patients with endometriosis who are attempting non-in vitro fertilization conception. However, EFI calculation requires laparoscopy. Newly established imaging techniques such as sliding sign, which is used to diagnose pouch of Douglas obliteration, could provide a promising alternative. The objective of this study was to investigate the practicality of using ultrasound data to predict a low EFI (score ≤6).

DESIGN

Observational study from a prospective registry (Endometriosis Pelvic Pain Interdisciplinary Cohort, clinicaltrials.gov #NCT02911090). Analyzed data were captured from December 2013 to June 2017.

SETTING

Tertiary referral center at British Columbia Women's Hospital.

PATIENTS

We analyzed data for 2583 participants from the Endometriosis Pelvic Pain Interdisciplinary Cohort. In this cross-sectional study, we included 86 women aged <40 years.

INTERVENTIONS

Dynamic ultrasonography for the sliding sign testing and EFI calculation during laparoscopic surgery.

MEASUREMENTS AND MAIN RESULTS

Logistic regression was used to obtain receiver operating characteristic area under the curve (AUC) for the prediction models. Significance was p <.05. Patients with a negative sliding sign were older and had severe endometriosis and longer duration of infertility. Patients with a negative sliding sign had significantly lower total EFI scores and lower surgical factors scores than patients with a positive sliding sign. Logistic regression showed that a negative sliding sign and EFI historic factors score can predict an EFI score ≤6 (sensitivity = 87.9%, specificity = 81.1%, AUC = 0.93 [95% confidence interval, 0.88-0.98]). Adding the diagnosis of endometrioma to the previous prediction model resulted in AUC = 0.95 (95% confidence interval, 0.90-0.995), sensitivity = 84.8%, and specificity = 92.5%.

CONCLUSION

The sliding sign could be a potential alternative to the EFI surgical factors, and it could be used in combination with EFI historic factors and the diagnosis of endometrioma to predict an EFI score ≤6 for patients who are not scheduled for immediate surgery.

Imaging techniques in endometriosis

Endometriosis is a common gynecological condition affecting up to 15% of the general female population. Here, we present a systematic review of imaging techniques of endometriosis. The aim of this review is to determine the most accurate site-specific preoperative diagnostic tools in order to map, locate, evaluate the extension, and stage the disease. There are important reasons to stage endometriosis: to create a common language, to enable specificity of diagnosis, standardize comparisons, and to facilitate research applications. The requirements of an ideal endometriosis classification system are that it be empirically and scientifically based, be of general consensus, have unambiguous definition of terms, be comprehensive in all cases, have a simple translation from anatomic features to verbal description, reflect disease, predict fertility, predict pain relief, be useful to guide treatment, indicate risk of recurrence, identify clinical situations in which it does not apply, be simple to calculate, and be easy to communicate to women. An extensive search of papers regarding imaging techniques in endometriosis was performed in Pubmed from January 1992 to February 2018, including original peer-reviewed papers, reviews, and international guidelines.

Poor sensitivity of transvaginal ultrasound markers in diagnosis of superficial endometriosis of the uterosacral ligaments

Introduction:

This study aims to evaluate the use of transvaginal ultrasound in predicting superficial endometriosis near the uterosacral ligaments, in women with symptoms of endometriosis.

Methods:

This was a prospective observational pilot study in which women with symptoms of endometriosis underwent detailed pre-operative transvaginal ultrasound to assess the uterosacral ligament area for thickening (‘white line sign’), tenderness and small hypoechoic nodules. Women with deep infiltrating endometriosis were excluded. The test characteristics of transvaginal ultrasound were reported using histologically or visually proven endometriosis near the ipsilateral uterosacral ligament as a reference standard.

Results:

In 81 patients who underwent pre-operative transvaginal ultrasound and laparoscopy, no marker had appropriate test characteristics for a diagnostic or screening test for endometriosis near the ipsilateral uterosacral ligament when used alone. The presence of a small hypoechoic nodule on the white line had the highest specificity of the three markers, at 82% (95% confidence interval 66%–92%). Quantitative measurement of the white line also achieved a high specificity of ≥96% using a cut-off of 5.8 and 6.1 mm, on the left and right sides, respectively.

Conclusion:

Transvaginal ultrasound of the uterosacral ligament area using the three proposed markers is not a clinically useful screening test for superficial endometriosis near the uterosacral ligaments. A grossly thickened white line (≥5.8 mm) and/or the presence of small hypoechoic nodules are highly specific findings for superficial endometriosis near the uterosacral ligaments and may prompt surgical management.

Gel Sonovaginography: A New Way of Evaluating a Variety of Local Vaginal and Cervical Disorders

Gel sonovaginography is a new way of assessing local cervical and vaginal disorders, in which regular transvaginal sonography is known to have limitations. In gel sonovaginography, 20 mL of ultrasound gel is instilled into the vagina, followed by examination with a transvaginal transducer. In a study involving 28 women with known or suspected disorders such as cervical and vaginal cancer, cervical polyps, vaginal septa, and deep infiltrating endometriosis, a substantial improvement in visualization and assessment of local lesions and structures was noted with gel sonovaginography. This simple technique appears to be valuable for accurate diagnosis of local cervical and vaginal disorders.

Systematic approach to sonographic evaluation of the pelvis in women with suspected endometriosis, including terms, definitions and measurements: a consensus opinion from the International Deep Endometriosis Analysis (IDEA) group

The IDEA (International Deep Endometriosis Analysis group) statement is a consensus opinion on terms, definitions and measurements that may be used to describe the sonographic features of the different phenotypes of endometriosis. Currently, it is difficult to compare results between published studies because authors use different terms when describing the same structures and anatomical locations. We hope that the terms and definitions suggested herein will be adopted in centers around the world. This would result in consistent use of nomenclature when describing the ultrasound location and extent of endometriosis. We believe that the standardization of terminology will allow meaningful comparisons between future studies in women with an ultrasound diagnosis of endometriosis and should facilitate multicenter research. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

The use of intra-operative saline sonovaginography to define the rectovaginal septum in women with suspected rectovaginal endometriosis: a pilot study

Objectives: The aim of this study was to perform saline sonovaginography (SVG) in women with suspected rectovaginal endometriosis (RVE) in order to establish the thickness of the rectovaginal septum (RVS) in this population and to predict the presence or absence of RVE. Methods: Prospective observational pilot study. Women undergoing laparoscopy for possible endometriosis on the basis of history or clinical examination were offered to participate in the study. All women underwent saline SVG during general anesthesia just prior to their laparoscopy. RVS nodules were visualised as hypoechoic lesions of various shapes. The sonologist predicted whether or not a nodule was present in the retrocervical area or in the RVS. The thickness of the posterior vaginal wall ± RVS was then taken at three points in the mid-sagittal plane: at the posterior fornix (retrocervical area), at the middle third of the vagina (upper RVS) and just above the perineal body (lower RVS). The diagnosis of RVE was established using the gold standards of laparoscopy and histological confirmation. The RVS thickness was then compared between women with RVE and the absence of RVE. Results: Twenty-three women were enrolled in the study. Mean age was 38 years (33-44 years). A history of endometriosis was present in 72.7% (8/11). RVE was confirmed in 17.4% (4/23). Visualisation of a hypoechoic nodule at saline SVG demonstrated sensitivity and specificity of 75% and 95%, respectively. All rectovaginal nodules were located in the retrocervical region. Mean diameter (SD) of RVE nodules was 27.3 (± 9.4) mm. Mean thickness of vaginal wall ± RVS at the posterior fornix, at the middle third of the vagina and just above the perineal body was 5.1, 1.4 and 4.0 mm, respectively. These measurements were not significantly different in the presence of a rectovaginal nodule. Conclusions: Using saline SVG, we have established the mean RVS thickness in a small group of women with suspected RVE. Although the numbers are small, there was no correlation between RVS thickness and presence of RVE. The visualisation of hypoechoic lesions at saline SVG seems to be the best ultrasonographic predictor for RVE. SVG is a valuable pre-operative tool for the assessment of RVS and for the prediction of RVE, which allows for the mapping and planning of advanced endometriosis surgery.

Systematic evaluation of women with suspected endometriosis using a 5-domain sonographically based approach

In recent years, knowledge has evolved regarding the role of transvaginal sonography in the assessment of the pouch of Douglas status and the preoperative prediction of extraovarian endometriosis in specific locations. Despite these advances in transvaginal sonography, the challenge of developing a comprehensive, cost-effective, and reproducible preoperative classification system for endometriosis remains. Critical to this classification system should be a sonographically based evaluation protocol that is systematic, evidence based, and reproducible with clearly defined end points. To date, no structured evaluation protocol exists for the assessment of the pelvis in women with suspected endometriosis. In this article, we propose a domain-based evaluation protocol for the assessment of women with suspected endometriosis using transvaginal sonography.

The 'sliding sign' in conjunction with sonovaginography: is this the optimal approach for the diagnosis of Pouch of Douglas obliteration and posterior compartment deep infiltrating endometriosis?

Introduction: Endometriosis is a chronic peritoneal disease that may progress as a deep infiltrating lesion involving the posterior compartment of the pelvis. Efforts to improve pre-operative knowledge of the location and extent of these lesions have resulted in the development of Transvaginal ultrasound (TVS) as the first-line imaging modality for extra-ovarian endometriosis. However, various techniques of TVS have been described in the literature for this purpose. Methods: In this review we will detail the evolution of TVS as the primary imaging modality in the pre-operative diagnosis of posterior compartment deep infiltrating endometriosis (DIE). We will also discuss the potential of an emerging new real-time diagnostic ultrasound-based technique known as the 'sliding sign' in combination with office gel sonovaginography for the pre-operative diagnosis of Pouch of Douglas obliteration and posterior compartment DIE. Conclusion: Implementation of the new real-time dynamic, reproducible and simple 'sliding sign' in conjunction with SVG has the potential to challenge the current concept that traditional laparoscopy is the 'gold standard' modality for the diagnosis of women with posterior compartment DIE.