Utility of ultrasound for endometriosis
Ultrasound is the first-line imaging modality for reproductive or abdominopelvic complaints in women. The majority of patients who seek medical attention for possible endometriosis-related symptomatology are referred for pelvic ultrasound, which is traditionally done transabdominally and/or transvaginally. The American Institute of Ultrasound in Medicine (AIUM) recommends pelvic ultrasound that includes assessment of the uterus, ovaries, and rectouterine pouch for “fluid or mass.”13 This is what we classify as basic pelvic ultrasound.
Essentially, basic pelvic ultrasound has the potential to diagnose OE. Although DE commonly exists in the rectouterine pouch, also known as the pouch of Douglas (POD) or cul-de-sac, it is not typically described as “mass”-like and the vast majority of sonographers/radiologists are not trained to identify and document it. In addition to performing the elements of a basic pelvic ultrasound, we advocate for an advanced evaluation in all patients with endometriosis-related symptomatology that is in line with the recommendations of the International Deep Endometriosis Analysis (IDEA) group.14 We have dubbed this advanced pelvic ultrasound and it includes direct visualization of anatomic structures in the anterior and posterior compartments for DE and assessment of pelvic organ mobility. Specifically, within the anterior compartment, the bladder and ureters should be evaluated. The posterior compartment consists of the bowel, uterosacral ligaments (USLs), torus uterinus, posterior vaginal fornix (PVF), rectovaginal septum (RVS), and rectouterine pouch. Assessment of pelvic organ mobility is necessary and highly clinically useful due to the strong likelihood of adhesion development in those with endometriosis.
Most important is evaluation of the state of the rectouterine pouch, the area between the cervix/posterior vagina and bowel in the anterior/posterior plane and between the USLs in the lateral plane. This potential space may become “obliterated” (i.e. no longer a potential space), which can be appreciated by using the sliding sign technique.15 Ovarian mobility is also relevant and can be assessed along the pelvic sidewall laterally, USL inferiorly, or uterus medially.16 Often, the ovarian is adherent to an area of endometriosis and involves an OE.
The literature supports use of ultrasound for endometriosis.12,17,18 Several ob/gyn governing bodies that produce clinical guidelines are also beginning to acknowledge the use of the technology for endometriosis.5,19 A Cochrane systematic review and meta-analysis on diagnostic accuracy studies completed in 2016 demonstrated that for OE, transvaginal ultrasound (TVS) has sensitivity of 93% and specificity of 96%. For DE, TVS has a sensitivity of 79% and specificity of 94%. Reid et al. demonstrated that the sliding sign predicts obliteration of the rectouterine pouch with accuracy of 93%, sensitivity of 83%, and specificity of 97%.15
In 2016, the IDEA group published a consensus opinion with the aim of increasing awareness, improving education on endometriosis ultrasound mapping, and decreasing heterogeneity between published reports on diagnostic accuracy.14 Although the meta-analysis demonstrates a good diagnostic accuracy for ultrasound, it is likely limited due to multiple units using varying scanning methods and sometimes conflicting nomenclature. A classic example is use of the term rectovaginal endometriosis, which is not a true anatomic structure but a general area. The IDEA consensus opinion publication and growing expertise in endometriosis ultrasound both broadly and locally should actually yield even greater diagnostic accuracy now than in the past.
- Giudice LC. Endometriosis. N Engl J Med. 2010;362:2389-2398.
- Adamson GD, Kennedy S, Hummelshoj L. Creating solutions in endometriosis: Global collaboration through the World Endometriosis Research Foundation. J Endometr. 2010;2:3-6.
- Leonardi M, Singh SS, Murji A, et al. Deep endometriosis: a diagnostic dilemma with significant surgical consequences. J Obstet Gynaecol Canada. 2018;40:1198-1203.
- Leyland N, Casper R, Laberge P, et al. Endometriosis: diagnosis and management. J Obstet Gynaecol Canada. 2010;32:S1-S28.
- American College of Obstetricians and Gynecologists. Practice Bulletin No. 114: Management of Endometriosis. Obstet Gynecol. 2010;116:223-236.
- Agarwal SK, Chapron C, Giudice LC, et al. Clinical diagnosis of endometriosis: a call to action. Am J Obstet Gynecol. 2019;220:354.e1-354.e12.
- Kho KA, Shields JK. Diagnosis and management of primary dysmenorrhea. JAMA. 2019;344:1-2.
- Benacerraf BR, Groszmann Y. Sonography should be the first imaging examination done to evaluate patients with suspected endometriosis. J Ultrasound Med. 2012;31:651-653.
- Somigliana E, Vercellini P, Vigano’ P, Benaglia L, Crosignani PG, Fedele L. Non-invasive diagnosis of endometriosis: The goal or own goal? Hum Reprod. 2010;25:1863-1868.
- Singh SS, Suen MWH. Surgery for endometriosis: beyond medical therapies. Fertil Steril. 2017;107:549-554.
- Menakaya UA, Rombauts L, Johnson NP. Diagnostic laparoscopy in pre-surgical planning for higher stage endometriosis: Is it still relevant? Aust New Zeal J Obstet Gynaecol. 2016;56:518-522.
- Nisenblat V, Bossuyt PMM, Farquhar C, Johnson N, Hull ML. Imaging modalities for the non-invasive diagnosis of endometriosis. Cochrane Database Syst Rev. 2016:Art. No.: CD009591. DOI: 10.1002/14651858.CD009591.
- AIUM Practice Guideline for the Performance of Ultrasound of the Female Pelvis. J Ultrasound Med. 2014;33:1122-1130.
- Guerriero S, Condous G, van den Bosch T, et al. 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. Ultrasound Obstet Gynecol. 2016;48:318-332.
- Reid S, Lu C, Casikar I, et al. Prediction of pouch of Douglas obliteration in women with suspected endometriosis using a new real-time dynamic transvaginal ultrasound technique: the sliding sign. Ultrasound Obstet Gynecol. 2013;41:685-691.
- Gerges B, Lu C, Reid S, Chou D, Chang T, Condous G. Sonographic evaluation of immobility of normal and endometriotic ovary in detection of deep endometriosis. Ultrasound Obstet Gynecol. 2017;49:793-798.
- Tompsett J, Leonardi M, Gerges B, et al. Ultrasound-based endometriosis staging system: validation study to predict complexity of laparoscopic surgery. J Minim Invasive Gynecol. 2019;26:477-483.
- Collins BG, Ankola A, Gola S, McGillen KL. Transvaginal US of endometriosis: looking beyond the endometrioma with a dedicated protocol. RadioGraphics. 2019;39:1549-1568.
- National Institute for Health and Care Excellent. Endometriosis: Diagnosis and Management.; 2017. nice.org.uk/guidance/ng73.
- Leonardi M, Condous G. How to perform an ultrasound to diagnose endometriosis. Australas J Ultrasound Med. 2018;21:61-69.
- Young SW, Groszmann Y, Dahiya N, et al. Sonographer-acquired ultrasound protocol for deep endometriosis. Abdom Radiol. 2019.
- Timmerman D, Valentin L, Bourne TH, Collins WP, Verrelst H, Vergote I. Terms, definitions and measurements to describe the sonographic features of adnexal tumors: a consensus opinion from the International Ovarian Tumor Analysis (IOTA) group. Ultrasound Obstet Gynecol. 2000;16:500-505.
- Van Holsbeke C, Van Calster B, Guerriero S, et al. Endometriomas: Their ultrasound characteristics. Ultrasound Obstet Gynecol. 2010;35:730-740.
- Redwine DB. Ovarian endometriosis: A marker for more extensive pelvic and intestinal disease. Fertil Steril. 1999;72:310-315.
- Exacoustos C, De Felice G, Pizzo A, et al. Isolated ovarian endometrioma: a history between myth and reality. J Minim Invasive Gynecol. 2018;25:884-891.
- American Society for Reproductive Medicine. Revised American Society for Reproductive Medicine classification of endometriosis: 1996 American Society for Reproductive Medicine. Fertil Steril. 1997;67:817-821.
- Adamson GD, Pasta DJ. Endometriosis fertility index: the new, validated endometriosis staging system. Fertil Steril. 2010;94:1609-1615.
- Chapron C, Fauconnier A, Vieira M, et al. Anatomical distribution of deeply infiltrating endometriosis: Surgical improblications and proposition for a classification. Hum Reprod. 2003;18:157-161.
- Khan MAS, Ang CW, Hakeem AR, Scott N, Saunders RN, Botterill I. The impact of tumour distance from the anal verge on clinical management and outcomes in patients having a curative resection for rectal cancer. J Gastrointest Surg. 2017;21:2056-2065.
- Leonardi M, Condous G. A pictorial guide to the ultrasound identification and assessment of uterosacral ligaments in women with potential endometriosis. Australas J Ultrasound Med. 2019;22:157-164.
- Leonardi M, Martins WP, Espada M, Arianayagam M, Condous G. A proposed technique to visualize and classify uterosacral ligament deep endometriosis with and without infiltration into the parametrium or torus uterinus. Ultrasound Obstet Gynecol. April 2019:uog.20300.
- Bean E, Naftalin J, Jurkovic D. How to assess the ureters during pelvic ultrasound. Ultrasound Obstet Gynecol. 2018.
- Aas-Eng K, Salama M, Sevelda U, Ruesch C, Nemeth Z, Hudelist G. Learning curve for detection of the distal part of ureters by transvaginal sonography (TVS): a feasibility study. Ultrasound Obstet Gynecol. June 2019.
- Khong SY, Bignardi T, Luscombe G, Lam A. Is pouch of Douglas obliteration a marker of bowel endometriosis? J Minim Invasive Gynecol. 2011;18:333-337.
- Robinson AJ, Rombauts L, Ades A, Leong K, Paul E, Piessens S. Poor sensitivity of transvaginal ultrasound markers in diagnosis of superficial endometriosis of the uterosacral ligaments. J Endometr Pelvic Pain Disord. 2018;10:10-17.
- Reid S, Leonardi M, Lu C, Condous G. The association between ultrasound-based ‘soft markers’ and endometriosis type/location: A prospective observational study. Eur J Obstet Gynecol Reprod Biol. 2019;234:171-178.
- Chowdary P, Stone K, Ma T, et al. Multicentre retrospective study to assess diagnostic accuracy of ultrasound for superficial endometriosis—Are we any closer? Aust New Zeal J Obstet Gynaecol. 2019;59:279-284.
- Leonardi M, Espada M, Lu C, Stamatopoulos N, Condous G. A novel ultrasound technique called saline infusion sonoPODography to visualize and understand the pouch of Douglas and posterior compartment contents: A Feasibility Study. J Ultrasound Med. 2019;38:3301-3309.