{"paper_id":"de36e3c5-7302-4950-bd56-8aa8ce3d966f","body_text":"Systematic, noninvasive endometriosis diagnosis in transvaginal\nsonography by the Swiss Society of Ultrasound in Medicine\nSystematische, nicht invasive Endometriose-Diagnostik in der\ntransvaginalen Sonografie: Empfehlungen der Schweizerischen\nGesellschaft für Ultraschall in der Medizin\nAuthors\nJulian Matthias Metzler 1, 2 , Leana Finger 2,T i l oB u r k h a r d t3, 2 , Markus Eugen Hodel 4, Gwendolin Manegold-Brauer 5 ,\nSara Imboden 6, 7, Janna Pape 8, 7,P a t r i c kI m e s c h1, 2, Isabell Witzel 1, 2, Michael Bajka 1, 2\nAffiliations\n1 Gynecology, University Hospital Zurich, Switzerland\n2 Faculty of Medicine, University of Zurich, Switzerland\n3 Obstetrics, University Hospital Zurich, Switzerland\n4 Obstetrics and Gynecology, Cantonal Hospital Lucerne,\nSwitzerland\n5 Prenatal medicine and gynecologic ultrasound, University\nHospital, Basel, Switzerland\n6 Gynecology, Inselspital University Hospital, Bern,\nSwitzerland\n7 Faculty of Medicine, University of Bern, Switzerland\n8 Gynecological Endocrinology and Reproductive Medicine,\nInselspital University Hospital, Bern, Switzerland\nKeywords\nendometriosis, ultrasound, transvaginal, sonography,\nclassification\nreceived 1.2.2024\naccepted 16.2.2024\npublished online 24.5.2024\nBibliography\nUltraschall in Med 2024; 45: 367 –388\nDOI 10.1055/a-2241-5233\nISSN 0172-4614\n© 2024. Thieme. All rights reserved.\nGeorg Thieme Verlag KG, Rüdigerstraße 14,\n70469 Stuttgart, Germany\nCorrespondence\nDr. Julian Matthias Metzler\nGynecology, University Hospital Zurich, Frauenklinikstraße 10,\n8091 Zürich, Swit zerland\nTel.: +41/44/2 55 50 36\njulian.metzler@usz.ch\nABSTRACT\nWe present a new systematic, comprehensive, checklist-based\nsonographic assessment of endometriosis in the female true\npelvis. Emphasis is placed on practical skills teaching. The newly\nintroduced White Sliding Line (WSL) is the core structure. The\nWSL separates five compartments (anterior, central, posterior,\nand lateral right and left) conta ining dedicated endometriosis\nsigns of mobility and morphology to be checked. This approach\nrelies on the 2016 IDEA Consensus and further developments. It\ndirectly connects to the 2021 #ENZIAN Classification Standard.\nIn practice, evaluation follows the proposed checklist in all com-\npartments, judging first sliding mobility between organs and\nstructures in a highly dynamic investigation. A rigorous search\nfor deep endometriosis (DE) is then performed. We treat adhe-\nsions due to their great clinical importance and possible, reliable\ndiagnosis by TVS as the fifth endometriosis unit, next to endo-\nmetrioma, DE, adenomyosis, and superficial endometriosis. In-\ncluding superficial (peritoneal) endometriosis is a future goal.\nZUSAMMENFASSUNG\nWir präsentieren eine systematische, umfassende, auf einer\nCheckliste basierende sonografische Abklärung der Endome-\ntriose im weiblichen kleinen Becken. Das Übermitteln prakti-\nscher Fähigkeiten stellt einen Schwerpunkt dar. Der neu ein-\ngeführten White Sliding Line (WSL) kommt dabei eine\nSchlüsselrolle zu. Die WSL ermöglicht die Einteilung in 5 Kom-\npartimente (anterior, zentral, posterior und lateral rechts und\nlinks). Diese enthalten dedizierte Endometriose-Zeichen zur\nMobilität und Morphologie. Die vorgeschlagene Systematik be-\nruht auf dem IDEA-Konsensus von 2016 und dessen Erweiterun-\ngen. Sie leitet direkt in die #Enzian-Klassifikation von 2021 über.\nIn der Praxis wird gemäß der Checkliste in einer betont dynami-\nschen Untersuchung nach reduziertem oder aufgehobenem\nSliding zwischen Organen und Strukturen gefahndet, gefolgt\nvon einer rigorosen Suche nach tiefen Endometriose-Läsionen.\nDie große klinische Bedeutung der Adhäsionen und ihre zuver-\nlässige sonografische Beurteilbarkeit lässt uns diese als 5. Enti-\ntät der Endometriose behandeln, nebst Endometriomen, tiefer\nEndometriose, Adenomyose und oberflächlicher Endometriose.\nIn Zukunft soll möglichst auch die oberflächliche (peritoneale)\nEndometriose in die Systematik aufgenommen werden.\nGuidelines & Recommendations\n367Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\nArticle published online: 2024-05-24\n\n1 Objective\nTransvaginal sonography (TVS) is the standard examination method\nof the female pelvis and is now the recommended first-line ima-\nging modality to diagnose endometriosis [1 –3]. In the hands of\nexperienced examiners, TVS offers high sensitivity and specificity\n[4] for diagnosing ovarian endome triosis (endometrioma) [5],\nadenomyosis [6, 7], deep endome triosis (DE) [8, 9], and adhe-\nsions [4]. In symptomatic patients, not only adenomyosis and DE\nare prevalent findings, but also a negative Sliding Sign in 25 % of\ncases, and the loss of ovarian mobility in 20 % [10]. On the other\nhand, the sonographic detection of peritoneal endometriosis is\nstill challenging [11].\nThe sonographic appearance of recognizable endometriotic le-\nsions on TVS may be briefly summarized as direct and indirect\nsigns. Direct signs (endometrio mas, space-occupying lesions of\nlow echogenicity) are indicators of DE. Indirect signs (reduced or\nabsent sliding mobility between organs, evidence of tissue ten-\nsion, painful areas) are indicators of adhesions. An encompassing\nchecklist protocol for endometriosis assessment, including both\ndirect and indirect signs, is still needed [10].\nThis article presents a new, comprehensive, and systematic\napproach by the Swiss Society of Ultrasound in Medicine\n(SGUM) (SWISS Gynecologic Ultrasound Guideline, 3\nrd edition,\nin press) to explore the entire female true (lesser) pelvis in five\ncompartments for endometriotic lesions using TVS. It is based\non the 2016 IDEA Consensus (IDEA 2016) [8], including subse-\nquent extensions [11, 12], refinements [6, 13], and validations\n[4, 14]. It highlights the five sites most commonly affected by\nDE (sacrouterine ligaments (SUL) 53 %, bowel 23 %, vagina 16 %,\nbladder 6 %, and ureters 2 %) [15]. It also explains how the well-\nknown sliding mobility can be expanded and applied using\nthe unique strength of TVS: a highly dynamic investigation.\nFinally, the description of endometriosis findings proposed by\nthe #ENZIAN Endometriosis Classification (#ENZIAN) from 2021\nis used as an essential summary that allows comparability across\ncases, imaging modalities, and disciplines [16].\nWe focus on teaching practical skills. In addition to the text, QR\ncode-backed instructional figure s (fig.), videos (vid.), and tables\n(tab.) help the reader to master the highly dynamic examination.\n2 Transvaginal sonographic image orientation\nFor TVS image orientation in sagittal planes, a headstand or foot-\nstand is used with patients looking either to the right or left\n(▶ Fig. 1). Following the central European standard [17, 18], we\nhave chosen the TVS image orientation with the woman standing\nupright looking to the right, also presenting her bladder on the\nright side ( ▶ Video 1 ). The second main plane used is the trans-\n▶ Fig. 1 Different TVS image orientations in use. MRI: magnetic\nresonance imaging; TVS: transvaginal sonography.\nOP-VIDEO\n▶ Video 1 Applied TVS image orientation. MRI: magnetic reso-\nnance imaging; TVS: transvaginal sonography\n▶ Fig. 2 Recommended TVS view. LSC: laparoscopy; TVS: transva-\nginal sonography.\nOP-VIDEO\n▶ Video 2 How to reach footstand TVS view\n368 Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nGuidelines & Recommendations\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\nverse plane. It runs from right to left and is ideal for lateral com-\nparisons. The investigators should consciously choose and switch\nbetween sagittal and transverse planes and use them to start a\ndynamic examination with individually adapted planes.\nMatching the TVS view with the laparoscopic (LSC) view is cru-\ncial for preoperative diagnosis communication. Unlike TVS, the\nLSC view shows the sliding peritoneal surface at a glance. We,\ntherefore, recommend the important sliding mobility exploration\nin TVS by working with a mental image of the typical LSC view\n(looking down from the umbilicus to the pelvis) ( ▶ Fig. 2). TVS ex-\naminers who choose the image orientation with the woman on\nthe handstand (top-down) may work directly with the LSC view.\nTo match the footstand image orientation in TVS (bottom-up)\nwith the LSC view ( ▶ Fig. 2), examiners should turn the mental\nLSC image 180 degrees ( ▶ Video 2).\n3 Extending the sliding sign for comprehensive\nendometriosis diagnosis\nWe use mobility for any shifting, position change, or dislocation of\norgans and structures, spontaneously occurring or manually pro-\nvoked. Sliding mobility , or simply sliding, refers to the physiological\nshifting of organs and structures against each other along two\nsurfaces.\nWe propose extending the sliding sign , formerly described as\nsliding limited to the back side of the uterus [19, 20], in any direc-\ntion to analyze all sliding mobility visible in the true pelvis. In a\nhighly dynamic investigation, looking for impairment or even loss\nof sliding should be the first step in TVS assessment, as when\nsearching for adhesions and detecting endometriotic lesions or\ntumors [19, 20].\n3.1 The White Sliding Line (WSL)\nThe critical element for judging the sliding mobility in the pelvis is\nestablishing the White Sliding Line (WSL, ▶ Fig. 3)i nt h e mid-sagit-\ntal plane through the uterus. With the gently continuous applica-\ntion of pressure against the anteflexed uterus and the vaginal wall\nby the ultrasound probe from the anterior fornix (from the poster-\nior fornix in the case of a retroflexed uterus), the complete uterine\nsurface gets progressively exposed as a curved thin white line, re-\npresenting the central part of the WSL (▶ Fig. 3 right, ▶ Video 3).\n▶ Fig. 3 White Sliding Line (WSL). RVS: rectovaginal septum; VVS: vesicovaginal septum.\nOP-VIDEO\n▶ Video 3 White Sliding Line (WSL). VVS: vesicovaginal septum;\nRVS: rectovaginal septum\nOP-VIDEO\n▶ Video 4 Compartmentation. Image on the right: adapted from\nSchünke M, Schulte E, Schumacher U, Voll M, Wesker K. 6.23\nSchnittbildanatomie des weiblichen Beckens. In: Schünke M,\nSchulte E, Schumacher U, Voll M, Wesker K, Hrsg. Prometheus\nLernAtlas – Innere Organe. 5. Auflage. Stuttgart: Thieme; 2018.\ndoi:10.1055/b-006 –149 645\n369Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\nPhysiologically, the WSL shows free sliding between the uterus\nand its surroundings. Posteriorly, at the posterior fornix, this white\nline merges directly into the equally echogenic rectovaginal sep-\ntum (RVS)( ▶ Fig. 3 left). It runs at the backside of the vagina\ndown to the anal verge. Anteriorly, at the anterior fornix, this\nwhite line merges directly into the equally white-appearing vesi-\ncovaginal septum (VVS)( ▶ Fig. 3 right). It runs to the introitus first\nbetween the vagina and the bladder, then between the vagina\nand urethra. Optimum dynamic exposure shows this line as a con-\ntinuous white line from the ventral introitus along the anterior\nvaginal wall around the uterus and the backside of the vagina dor-\nsally to the anal verge ( ▶ Video 3).\nThe mid-sagittal WSL can be accompanied by the other sagittal\nplanes through the uterus and vagina from right to left. The accu-\nmulation of all resulting white lines around the uterus and vagina\nrepresents an almost closed white 3 D envelope ( ▶ Fig. 4), which\ncorresponds to the well-known uterovaginal fascia [21]. Further-\nmore, the WSL plays an essential role by defining clear and reliable\nborders between the five compartments.\n3.2 The tent sign, tail sign, and omega sign\nIf the ultrasound probe is rotated in the transverse plane while\nmaintaining constant, gentle pressure, an echogenic, sharp\nwhite line runs horizontally from right to left along the back of\nthe uterus, visible from the fundus to the cervix. Like the WSL,\nit corresponds to the serosa of the uterus. We call it the tent\nsign (▶ Fig. 5, ▶ Video 5 ). Tracking the prolongation of the tent\nsign laterally beyond the uterus at the dorsal sheet of the broad\nligament and further to the lateral pelvic sidewall results in a tail-\nlike curved white line, which we call the right and left tail sign\n(▶ Video 5 ). We refer to the resulting closed white line, repre-\nsenting the tent sign in the center and the left and right tail signs\nmid-sagittal\nserosa\nadventitia\nVVS\nRVS\n▶ Fig. 4 White Sliding Line (WSL) right-left extension. RVS: rectovaginal septum; VVS: vesicovaginal septum. Image on the right: adapted from\nSchünke M, Schulte E, Schumacher U, Voll M, Wesker K. 6.23 Schnittbildanatomie des weiblichen Beckens. In: Schünke M, Schulte E, Schumacher U,\nVoll M, Wesker K, Hrsg. Prometheus LernAtlas – Innere Organe. 5. Auflage. Stuttgart: Thieme; 2018. doi:10.1055/b-006 –149 645.\n▶ Fig. 5 Tent sign, tail sign, and omega sign.\n370 Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nGuidelines & Recommendations\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\non the laterals as the omega sign (▶ Fig. 5, ▶ Video 5, 6 ). Sliding\nalong the omega sign should be fully detectable on the entire\nposterior surface of the uterus and broad ligaments.\n4 Practical approach for endometriosis\ndiagnosis by TVS\nPelvic endometriosis evaluation by TVS starts with the basic sono-\ngraphic examination as usual ( “basic TVS”) [17, 18]. All non-endo-\nmetriotic findings should be described and proceed following the\ngiven standards. The comprehensive evaluation for endometriosis\nis directly connected to the basic examination. The examiners\nshould strictly follow a well-dev eloped examination protocol\n(▶ Table 2 ). The presented concept shows the suggested se-\nquence for working through the compartments and structures\n(▶ Table 1, 2, ▶ Video 4). We propose the application of five com-\npartments in the pelvis ( ▶ Table 1, ▶ Video 4 ), defined by the\nWSL, containing a total of 35 relevant sliding qualities, structures,\nand organs ( ▶ Table 2), as described in IDEA 2016 [8] and its ex-\ntensions. Our proposal provides direct preparation for classifying\nthe endometriotic findings with #ENZIAN [16] ( ▶ Fig. 6).\nThe term nodule is suitable for describing the palpable find-\nings of a hard nodular resistance in the pelvis. In contrast, on\nTVS, endometriotic lesions typically appear as discrete, blurred,\nhypoechoic changes in the tissue of varying size and shape in fa-\nvored locations. They often do not resemble a nodule and are\nhard to detect. Therefore, the term lesion should be preferred\nfor TVS.\nIDEA 2016 and #ENZIAN [8, 16] define only lesions at a sub-\nperitoneal depth of 5 mm or more as DE. All thinner lesions are\ncounted as superficial. For hollow organs such as bowels, blad-\nder, and ureters, DE partial thickness defects reach the muscu-\nlar layer, and DE full thickness defects involve the complete\nmuscular layer. They may reach or even penetrate the submu-\ncosal layer. The infiltrated layers should be documented (adven-\ntitia/peritoneal border, muscularis, submucosa, mucosa/urothe-\nlium).\nConscious navigation through the pelvis, exposing the region\nof interest as best possible, is mandatory to avoid missing rele-\nvant pathologies while taking the patient ’s comfort into account\nat the same time. The examiner ’s free hand rests on the supra-\npubic region and gently applies pressure toward the true pelvis,\nsupporting the exposure of dedicated structures and sliding be-\ntween them. We use the following self-explaining terminology to\ndescribe the movements of the ultrasound probe : up, down,\nright, left, push, pull, and rotate . It is important to note that\nthe pen-like ultrasound probe used for TVS pivots around an in-\ntravaginal center point close to the introitus, and the terminol-\nogy describes the movements of the probe tip . In contrast, the\nprobe guiding hand must move automatically in the opposite di-\nrection for the pivoting motions, which are up, down, right, and\nleft.\nThe proper machine settings, mainly the optimal magnifica-\ntion scale, allow the inspection of the investigated structure/or-\ngan (region of interest) in detail at a glance.\nOP-VIDEO\n▶ Video 5 Tent sign, tail sign, and omega sign\nOP-VIDEO\n▶ Video 6 Pelvic sidewall. CAL: cardinal ligament; SUL: sacrouterine\nligament\n▶ Table 1 Compartment Definition.\nCompartments Definitions Content\nLeading structure “White Sliding\nLine” (WSL)\nWSL, VVS, RVS\nAnterior Ventral to WSL Sliding, bladder,\nureters\nCentral Enclosed by WSL Tent sign, uterus,\nvagina, POD\nPosterior Posterior to WSL RVS, rectum\nLateral right/left Lateral to WSL\n(lateral to uterus/\nvagina)\nSliding, omega\nsign, ovaries,\ntubes, uterus,\nbowel, ligaments\nWSL: White Sliding Line; VVS: vesicovaginal septum; RVS: rectovaginal\ns e p t u m ;P O D :p o u c ho fD o u g l a s\n371Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\n▶ Table 2 Checklist.\nChecklist Endometriosis evaluation\nProcedure Examination\nsequence\nDefinition, mobility, and organs/structures #ENZIAN classification Findings DOC*\nPreparation 1 Routine transvaginal s onography (TVS) including\nbiometry and description of any other pathology\nthan endometriosis or adenomyosis (polyps, myo-\nmas, congenital anomalies, adnexal tumors, etc.)\n2 Expose the complete sagittal White Sliding Line (WSL)\nCompartment\nevaluation\nAnterior Definition: ventral to WSL\nSliding (impaired?\nblock sign ?)\n3 Vesicouterine region (VUR) Fb\n4 Bladder dome Fb\nLesion (DE?) 5 Bladder wall** (trigonum, base, dome, extra-\nperitoneal)\nFb\n6 Vesicovaginal septum (VVS) Fb\n7U r e t e r r i g h t F u\n8U r e t e r l e f t F u\nCentral Definition: enclosed by WSL\nSliding (impaired?\nblock sign ?)\n9 Uterine serosa ( WSL)T 2 , 3\n10 Tent sign (entire dorsal uterine serosa), transverse T2,3\n11 Pouch of Douglas (POD) T2/3\nLesion (DE? super-\nficial?)\n12 Adenomyosis Fa\n13 Vaginal wall anterior A\n14 Vaginal fornix anterior A\n15 Vaginal fornix posterior A\n16 Vaginal wall posterior A\nPosterior Definition: posterior to WSL\nLesion\n(DE? superficial?)\n17 Rectovaginal septum (RVS) A\n1 8 R e c t a lw a l la n t e r i o r( <1 6c mt oa n a lv e r g e ) * * C\n19 Intestinal wall anterior (> 16 cm to anal verge)** Fi\nLateral Definition: lateral to WSL\nRight Right\nSliding (impaired?\nblock sign ?)\n20 Right tail sign T1,2,3\n21 Between ovaries, tubes, uterus, bowel, ligaments T1,2,3\nLesion\n(DE? superficial?)\n22 Broad ligament (dorsal sheath) B\n23 Pelvic sidewall B\n24 Cardinal ligament (CAL) B\n25 Sacrouterine ligament (SUL) B\n26 Endometrioma(s) O\n27 Tube*** T\n372 Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nGuidelines & Recommendations\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\nDownload available on www.sgumgg.ch\n▶ Table 2 (Continuation)\nChecklist Endometriosis evaluation\nProcedure Examination\nsequence\nDefinition, mobility, and organs/structures #ENZIAN classification Findings DOC*\nLeft Left Left/right\nSliding (impaired?\nBlock Sign ?)\n28 Left tail sign T1,2,3 T /\n29 Between ovaries, tubes, uterus, bowel, ligaments T1,2,3 T /\nLesion\n(DE? superficial?)\n30 Broad ligament B B /\n31 Pelvic sidewall B B /\n32 Cardinal ligament (CAL) B B /\n33 Sacrouterine ligament (SUL) B B /\n34 Endometrioma(s) O O /\n35 Tube*** T T /\nForms of impaired sliding: free, reduced, fixed; DE lesion: definition by #ENZIAN ≥ 5 mm from the surface, measured in three dimensions; in bowel nodule:\nmeasure distance from anal verge to lowest end of lesions, indicate with or without internal obstruction.\n* documentation (photos, movies, drawings).\n** Definition of partial or full thickness defect by IDEA affecting bowel and bladder: in full thickness defect the nodule affects the complete muscular layer,\nin partial thickness defect only parts of it are affected.\n*** if visible.\n▶ Fig. 6 Compartmentation and #ENZIAN classification. TVS: transvaginal sonography.\n373Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\n4.1 Anterior compartment\n4.1.1 Definition\nThe anterior compartment is defined by organs and structures ven-\ntral to the WSL, principally represented by the bladder and the ur-\neters ( “urologic compartment ”)( ▶ Fig. 8, ▶ Video 7, ▶ Table 2).\nSliding should be observable along the WSL on the ventral uter-\nine serosa, at the bladder dome, and in the subperitoneal vesicou-\nterine region, corresponding to the adventitia ( ▶ Fig. 3), but not\nat the VVS. Impaired sliding mainly occurs at the surface of the\nbladder dome ( ▶ Fig. 9) due to adhesions to the bowel or at the\nbladder base. DE in this compartment appears preferably in the\nmedian part of the bladder at the bladder base ( ▶ Video 8 )o r\ndome and at the ureters at the undercrossing of the uterine vessel\ncomplex (UVC, containing the uterine artery) [22, 23]. Lesions\nmay affect all layers of the bladder and ureters, single or multiple.\nEndometriotic lesions affecting the bladder area are reported\nas #ENZIAN FB, and lesions affecting the ureters as #ENZIAN FU\n(▶ Fig. 7a) [16].\n4.1.2 Assessment\nA lightly or moderately filled bladder is advantageous. It may be\nnecessary to postpone the examination of this compartment to\nthe end of the workup if the bladder is empty.\nThe probe is placed in the center of the anterior vaginal fornix\nsagittally , also in retroflexed uteri. The proper settings, mainly\nthe optimal magnification scale, allow the inspection of the entire\nbladder circumference in one plane at a glance.\n4.1.3 Vesicouterine region (VUR)\nThe vesicouterine region is a typical site for reduced or absent\nsliding mobility due to endometriotic adhesions or prior surgery,\ncommonly seen after cesarean sections ( ▶ Video 9 ), but also for\nDE lesions ( ▶ Video 8 ), with or without the bladder wall being\naffected [24].\n▶ Fig. 7 a QR code for #ENZIAN-App in App store (Apple iOS);\nb QR code for #ENZIAN-App in Google Play store (Android).\n4 + 5 lateral\n2 central\n3\nposterior\n1 anterior\n▶ Fig. 8 Anterior compartment. Image on the right: adapted from Schünke M, Schulte E, Schumacher U, V oll M, Wesker K. 6.23 Schnittbildana-\ntomie des weiblichen Beckens. In: Schünke M, Schulte E, Schumacher U, Voll M , Wesker K, Hrsg. Prometheus LernAtlas – Innere Organe. 5. Auflage.\nStuttgart: Thieme; 2018. doi:10.1055/b-006 –149 645.\n374 Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nGuidelines & Recommendations\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\nOP-VIDEO\n▶ Video 7 Anterior compartment\nOP-VIDEO\n▶ Video 8 Bladder wall lesion after hysterectomy. DE nodule at the\nbladder base (red circle), full thickness defect. #ENZIAN: FB.\n▶ Fig. 9 Bladder regions. The trigonal zone (purple) is a smooth\ntriangular region bounded by the two ureteral openings and the in-\nternal urethral opening. The bladder base (green) is directed pos-\nteriorly and borders the vagina and the supravaginal portion of the\nuterine cervix. The bladder dome (red) is located above the base\nand is intraperitoneal. The extraperitoneal area (blue) of the bladder\nis located anteriorly or opposite the bladder dome.\nOP-VIDEO\n▶ Video 9 Sliding in the vesicouterine region (VUR).\nOP-VIDEO\n▶ Video 10 Vesico-vaginal septum (VVS). Dynamic investigation.\nOP-VIDEO\n▶ Video 11 Right distal ureter presentation\n375Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\n4.1.4 Bladder\nDE of the bladder belongs to the most common sites (number 4 of\nthe top 5, 6 %) [15]. Lesions may be discovered by consciously\nsteering the probe in a sagittal plane from right to left and then\nswitching to the transverse plane, moving from cranial to caudal\nfor scanning the entire bladder wall in all four zones ( ▶ Fig. 9)[ 8 ] .\n4.1.5 Vesicovaginal septum (VVS)\nWith correct sagittal exposure on TVS, the VVS appears as a thin\nwhite line, running from the pelvic floor to the cervix behind the\nvagina, representing its adventitia. The VVS is the ventral part of\nthe WSL. No physiological sliding is visible at the VVS between\nthe bladder wall or urethra and the vagina ( ▶ Video 10 ). These\nstructures may only be stretched, accompanied by remarkable\nbladder and vaginal wall thinning and displacement. DE lesions\nare rarely observed at this site.\n4.1.6 Right and left ureters\nTo assess the hypoechoic tubular right and left ureters, the\ninternal urethral meatus should first be identified sagittally\n(▶ Video 11, 12 ). The probe is then gently moved right or left\ntowards the investigated side, whereby the investigator ’sg u i d -\ni n gh a n dm a yc o m ec l o s et ot h ep a t i e n t’s contralateral thigh\nand rotated slightly outward (about 30 degrees clockwise for\nthe right side and 30 degrees counterclockwise for the left\nside). Identifying the intramural part of the ureter is facilitated\nby a lightly or moderately filled bladder. Waiting for peristalsis,\noccurring approximately 1 to 4 times per minute, also called\nvermiculation , is particularly helpful as it confirms kidney func-\ntion and ureter patency. Using CD, a high-flow urine jet into the\nbladder can often be documented, occasionally presenting color\nflow in the prevesical ureter ( ▶ Video 13). Visualization up to the\nunder-crossing of the UVC is usually successful ( ▶ Video 14 ).\nBeyond the pelvis, the ureters and the kidneys should be asses-\nsed by TAS for hydronephrosis. A urethral inner diameter of\nmore than 5 mm is suspicious for urethral obstruction [16]\nDE lesions at the dorsolateral cervix, potentially obstructing\nthe ureters, represent a common location (number 5 of the\ntop 5, 2 %) [15].\n4.2 Central compartment\n4.2.1 Definition\nThe central compartment is defined by organs and structures en-\ncircled by the WSL, principally represented by the uterus and vagina\n(“gynecologic compartment ”)( ▶ Table 2).\nSliding should be seen along the WSL on the entire free peri-\ntoneal surface, represented by the uterine serosa ( ▶ Fig. 10 ,\n▶ Video 15). Impaired or absent sliding may be seen on all parts\nof the serosa and should be carefully worked out dynamically\n(▶ Video 16 ). DE lesions in this compartment are common, oc-\ncurring preferably at the lower POD (levels II and III, ▶ Fig. 11)\nand the vaginal fornices, also affecting the vaginal wall [15].\nFurthermore, the uterus is checked in detail for signs of adeno-\nmyosis [6].\nOP-VIDEO\n▶ Video 12 Left distal ureter presentation\nOP-VIDEO\n▶ Video 13 Ureter jet sign. The jet sign occurs approximately 1 to\n4 times per minute.\nOP-VIDEO\n▶ Video 14 Ureter course. AUT: uterine artery; AII: iliacal internal\nartery; AIE: iliacal external artery\n376 Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nGuidelines & Recommendations\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\n4.2.2 Assessment\nThe anteflexed uterus should be visualized first sagittally with the\ntip of the TVS probe in the anterior vaginal fornix and the retro-\nflexed uterus in the posterior vaginal fornix [17].\nThe uterus ’ surface is checked for endometriotic lesions along\nthe WSL in sagittal and parasagittal planes and transverse planes\n(tent sign), including a profound assessment of the POD by a high-\nly dynamic investigation.\nThe anterior vaginal wall with the anterior fornix is inspected\nseparately by pulling the TVS pro be backward to the introitus\nwhile stretching the vaginal wall simultaneously, followed by ex-\namining the posterior vaginal wall the same way. These lesions\nare often smaller than 5 mm, so they do not fulfill the criteria of\nreal DE. Therefore, we call them endometriotic lesions or simply le-\nsions.\n4 + 5 lateral\n2 central\n3\nposterior\n1 anterior\n▶ Fig. 10 Central compartment. Image on the right: adapted from Schünke M, Schulte E, Schumacher U, Voll M, Wesker K. 6.23 Schnittbildana-\ntomie des weiblichen Beckens. In: Schünke M, Schulte E, Schumacher U, Voll M , Wesker K, Hrsg. Prometheus LernAtlas – Innere Organe. 5. Auflage.\nStuttgart: Thieme; 2018. doi:10.1055/b-006 –149 645.\nOP-VIDEO\n▶ Video 16 Free uterus sliding\nOP-VIDEO\n▶ Video 15 Central compartment\n377Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\nAUT\nLevel I:\nretrouterine\nLevel III:\nretrocervical\nLevel II:\nSUL\n▶ Fig. 11 Sonographic approach to the pouch of Douglas. SUL: sacrouterine ligament; AUT: uterine artery. Image on the left: adapted from\nSchünke M, Schulte E, Schumacher U, Voll M, Wesker K. 6.23 Schnittbildanatomie des weiblichen Beckens. In: Schünke M, Schulte E, Schumacher U,\nVoll M, Wesker K, Hrsg. Prometheus LernAtlas – Innere Organe. 5. Auflage. Stuttgart: Thieme; 2018. doi:10.1055/b-006 –149 645.\nOP-VIDEO\n▶ Video 17 Free POD sliding. POD: pouch of Douglas, definition by\nIDEA 2016: the space behind the uterus.\nOP-VIDEO\n▶ Video 18 Impaired POD sliding. #ENZIAN: T 3/0.\n378 Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nGuidelines & Recommendations\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\n4.2.3 Pouch of Douglas (POD)\nThe POD is defined as the entire space between the posterior\nuterus and the anterior rectum [8]. We follow the suggestion of\nIDEA 2016 of splitting the POD into three levels but propose the\nfollowing division ( ▶ Fig. 11): The first level covers the area behind\nthe uterine corpus from the fundus to the SULs. The SULs repre-\nsent the narrow second level. The area behind the cervix from\nthe SULs to the bottom of the pocket counts as the third level.\nPhysiologically, the uterus freely slides within its serosa in the\nsurrounding area (free sliding) ( ▶ Video 17 ). Impaired sliding\ntypically occurs on the backside of the uterus along the WSL\n(▶ Video 18). With a specificity of 91 –100 % and a sensitivity of\n93–100 % for detecting local adhesions, it is a strong indicator of\nadhesions in the POD [19, 20]. Sliding may be judged as free,\nreduced, or absent ( ▶ Video 19 ), indicating the origin and end\nof a suspected adhesion, as well as the POD level (I, II, III) they\naffect. Occasionally, the uterus is found already in a forced posi-\ntion with the fundus leaning backward, leaving the cavity in the\nshape of a question mark ( question mark sign )( ▶ Video 20). This\nindicates significant adhesions pulling the uterine fundus or\ncorpus backward to the bowel or the posterior pelvic wall.\nA specific search should be conducted for adhesions and DE in\nthe POD between the uterus and other structures, such as the\nbowel and ovaries. Levels II (SUL) and III (retrocervical) are most\nfrequently affected. Adhesions in the POD are classified as\n# E N Z I A NT 2o rT 3(▶ Fig. 7) [16].\n4.2.4 Adenomyosis\nThe examiners should describe morphologic findings, especially\nall indicators of adenomyosis of the uterus, and assess them fol-\nlowing the revised MUSA criteria [6]. Direct signs indicate the\npresence of an ectopic endometrium in the myometrium (cystic\ninclusions, hyperechoic islands, echogenic sub-endometrial lines,\nand buds) ( ▶ Video 21 ). Indirect signs may result from myome-\ntrium remodeling (globular uterus, asymmetric myometrial thick-\nening, trans-lesional vascularity, fan-shaped acoustic shadows, ir-\nregular or disrupted junctional zone). Direct signs are diagnostic\nOP-VIDEO\n▶ Video 19 Sliding mobility – terminology\nOP-VIDEO\n▶ Video 20 Question mark sign\nOP-VIDEO\n▶ Video 21 Adenomyosis. CYS: cystic inclusions; ISL: hyperechoic\nislands, LIN: echogenic sub-endometrial lines: BUD: buds\nOP-VIDEO\n▶ Video 22 Normal vaginal wall. Normal vaginal wall may be\nstretched to < 3 mm thickness (dotted line).\n379Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\nfor adenomyosis, whereas indirect signs only serve as indicators.\nAdenomyosis is reported as #ENZIAN FA ( ▶ Fig. 7) [16].\n4.2.5 Vaginal wall\nThe vaginal walls belong to the three most common locations of\nendometriosis (number 3 of the top 5, 16 %) [15]. They should\nbe examined by palpation for single or multiple hard pinheads\nwith a diameter of a few millimeters and then by ultrasound.\nThe probe should be moved deliberately slowly from right to\nleft over the anterior and posterior vaginal wall, including the\nfornices ( ▶ Video 22 ). Inhomogeneities, cysts, and small no-\ndules in the vaginal wall are the typical findings ( ▶ Video 23 ).\nThey tend to rush away ( slip off sign ). In our experience, the tip\nof the probe may stretch the healthy vaginal wall to a thickness\nof less than 3 mm ( ▶ Video 24 ). Local enlargements in the\nstretched vaginal wall exceeding 3 mm could be the sole ultra-\nsound representation of palpable, firm nodules. Furthermore,\nexaminers should always search for the involvement of deeper\nstructures: in the first layer, the VVS (anterior compartment) or\nthe RVS (posterior compartment); in the second layer, the blad-\nder wall anteriorly or the rectum wall posteriorly; and to the\nsides, the sacrouterine ligaments (SUL), the cardinal ligaments\n(CAL), and the ovaries (lateral compartments). Lesions in the va-\nginal wall are classified as #ENZIAN A1 for largest diameter\n< 1 cm, A2 for 1 to 3 cm, and A3 for > 3 cm ( ▶ Fig. 7) [16].\n4.2.6 Vaginal fornices\nSuspicion of fornical endometriosis most frequently arises when a\nlesion occurs behind the cervix or when the posterior vaginal for-\nnix appears thickened. Other possible involvement should be clar-\nified (vagina, SUL, CAL, ureter, ovary, bowel). Rectovaginal lesions,\nwhich simultaneously involve the posterior fornix and the anterior\nrectal wall, are also referred to as “diabolo-like lesions ” due to their\ntypical angular hourglass-shaped appearance ( ▶ Fig. 12 ) [25].\nThese often-large lesions (with an average size of 3 cm) pass\nfrom the posterior fornix to the anterior rectal wall. They may be\nlocated below the peritoneum of the POD, rendering them poorly\nvisible during laparoscopy [26]. Lesions in the vaginal fornices are\nclassified as #ENZIAN A1 for largest diameter < 1 cm, A2 for 1 to\n3 cm, and A3 for > 3 cm ( ▶ Fig. 7) [16].\n4.3 Posterior compartment\n4.3.1 Definition\nThe posterior compartment is defined by organs and structures\ndorsal to the WSL, principally represented by the rectum/intestine\n(“bowel compartment ”)( ▶ Table 2).\nSliding mobility should be observable along the anterior rectal/\nintestinal serosa but not at the RVS ( ▶ Fig. 13, ▶ Video 25). DE le-\nsions in this compartment occur preferably in the upper RVS and\nthe anterior rectal wall.\n4.3.2 Assessment\nExamination of the rectum/intestine may be compromised by ex-\ncessively meandering bowel loops with steep curves and the view\nobscuring faces. Nevertheless, the anterior wall of the rectum/in-\ntestine is usually visible up to the pelvic brim. Keeping the probe\nclose to the target is crucial for appropriate image quality and\njudgment ( ▶ Fig. 14). Isolated DE lesions affecting the intestine\nare some of the most challenging lesions to detect.\n▶ Fig. 12 Diabolo-like lesion. Left: Native DE lesion. Right: Marked\nDE lesion (blue).\nOP-VIDEO\n▶ Video 23 Thickened vaginal wall. Palpation reveals a hard line of\ntiny nodules, 2 × 0.5 cm, 6 h, cranio-caudal in dorsal fornix. In TVS,\nthe VW presents an increased thickness > 3 mm (dotted red line)\nand inhomogeneous, small cystic irregularity. #ENZIAN: A2.\nOP-VIDEO\n▶ Video 24 Vaginal wall lesion – slip off sign. Palpation of a hard\nnodule of 20 × 5 mm in the right dorsal fornix. In TVS, no proper\nnodule is visible. The vaginal wall (VW) only presents an increased\nthickness > 3 mm (dotted red line) and inhomogeneous, small\ncystic irregularity, which tends to slip off. #ENZIAN: A2.\n380 Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nGuidelines & Recommendations\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\nWe propose starting with RVS and bowel examination at the\nanal verge, proceeding from caudal to cranial in sagittal and para-\nsagittal planes for RVS evaluation and then checking the anterior\nrectum/intestine from the posterior fornix following its center line\n(▶ Video 25 ). The bowel in the true pelvis, at least the anterior\nwall, may be visualized by TVS (8). Measuring rectal length is fea-\nsible [27].\nAt the deepest point of the peritoneal cavity, the RVS divides\ninto an anterior branch, corresponding to the cervical serosa\n(WSL), and a posterior branch, corresponding to the rectal serosa\n(▶ Video 26). This division is a topographic TVS landmark that re-\npresents the cranial end of the RVS and the beginning of the intra-\nabdominal free bowel.\n4.3.3 Rectovaginal septum (RVS) and bowel\nIn the case of reduced or absent sliding, examiners should de-\nscribe the degree of sus picion for adhesions ( ▶ Video 19 )a n d\nwhich organs are involved. DE lesions are judged to be either ret-\nrocervical, in the vaginal (fornix) wall, in the RVS (#ENZIAN A), or\npurely affecting the rectum (#ENZIAN C) ( ▶ Fig. 7)[ 1 6 ] .T h el a r -\ngest diameter in a sagittal midline plane along the axis of the rec-\ntum is measured, and severity is assigned regarding the size:\n< 1 cm (A1 or C1, respectively), 1 –3 cm (A2 or C2), > 3 cm (A3 or\nC3). The distance to the anal verge should be measured using\nthe ultrasound probe as a measuring tool [27]. Lesions above\n16 cm cranial to the anal verge are described as intestinal lesions\n(#ENZIAN FI) ( ▶ Fig. 7) [16].\nDE lesions of the bowel belong to the most common sites\n(number 2 of the top 5, 23 %) [15]. Rectal DE lesions may be asso-\nciated with a second intestinal lesion in more than 50 % of cases\n[8]. Typically, bowel endometriosis appears as irregular, hypoe-\nchogenic lesions affecting the bowel wall ( ▶ Video 27). These le-\nsions may present a regular elliptic shape but often exhibit an\nasymmetric, irregular shape, sometimes with spikes or tails.\nW o r k i n go u tt h ea f f e c t e dl a y e r s(▶ Fig. 14)i sc r u c i a ls i n c et h i s\nhas significant implications for surgical treatment. Retractions in-\nside the anterior rectal wall may be visible if a bowel lesion is fixed\n4 + 5 lateral\n2 central\n3\nposterior\n1 anterior\n3\nposterior\n▶ Fig. 13 Posterior compartment. Image on the right: adapted from Schünke M, Schulte E, Schumacher U, Voll M, W esker K. 6. 23 Schnittbild-\nanatomie des weiblichen Beckens. In: Schünke M, Schulte E, Schumacher U, Voll M, Wesker K, Hrsg. Prometheus LernAtlas – Innere Organe.\n5. Auflage. Stuttgart: Thieme; 2018. doi:10.1055/b-006 –149 645.\nOP-VIDEO\n▶ Video 25 Posterior compartment\n381Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\nto the uterus or cervix. This phenomenon has been described as\nthe Indian headdress sign or moose antler sign (▶ Video 28 ).\nLesions with progressive narrowing, like a tail, have been\ndescribed as the comet sign [8].\n4.4 Lateral compartments\n4.4.1 Definition\nThe right and left lateral compartments are defined by organs and\nstructures lateral to the WSL ( “adnexal compartment ”):( ▶ Fig. 15,\n▶ Video 29 , ▶ Table 2). The upper border of this compartment\ncorresponds to the cranial border of the external and common\niliac artery.\n4.4.2 Assessment\nThe lateral compartments are generally investigated starting in\nthe ipsilateral fornix using a transverse plane.\nSliding mobility should be verifiable along all peritoneal surfa-\nces, except at the broad ligament, where only the dorsal sheet is\naccessible ( ▶ Video 30, 31 ). The guiding sliding line is the trans-\nversally (horizontally) running omega sign (▶ Video 5), presenta-\nble on the backside of the uterus and broad ligaments.\nWhenever one or more tiny, hard nodules are palpated on the\nlateral posterior vaginal fornix, TVS should assign the nodule to\nthe vaginal wall, SUL, or components and organs in the peritoneal\ncavity, such as the ovary and bowel. Several of them may appear\nstuck together, and move as a block ( block sign , ▶ Video 32 ),\nwhich can also be recognized by the lack of physiological distance\nbetween them when the probe is withdrawn quickly.\n4.4.3 Ovaries\nEndometriomas represent a proper entity of endometriosis mani-\nfestation [5]. They affect only the ovaries, are typically asympto-\nmatic, and are found in > 10 % of women with subfertility [28].\nThey appear as one of the typical four elementary benign adnexal\ntumors [29]. In about 50 % of cases, endometriomas present a\nuniform pattern of a smooth-walled unilocular cyst of homoge-\nneous ground glass echogenicity, containing no acoustic stream-\n▶ Fig. 14 Sonoanatomy of visceral organs.\nOP-VIDEO\n▶ Video 27 Intestinal DE lesion. Mushroom-shaped lesion. Full\nthickness defect. #ENZIAN: FI.\nOP-VIDEO\n▶ Video 26 Rectovaginal septum (RVS) “splitting”. Blue circle: up-\nper end of RVS\n382 Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nGuidelines & Recommendations\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\ning [5]. Endometriomas are rarely isolated findings [30]. They\noften occur with other potentially painful endometriotic lesions,\nsuch as adhesions in > 70 % of cases and DE in > 50 % [28, 31].\nThe most common differential diagnosis is the self-limiting he-\nmorrhagic cyst, typically presenting a spider-web-like, retracting\nclot and resolving over time. Endometriomas should be documen-\nted in number, three perpendicular measurements each, and the\ntype appearance (typical or atypical) [5]. The sum of all endome-\ntrioma diameters should be calculated for each ovary (side-sep-\narated) and classified by #ENZIAN; O1 (sum of diameters < 3 cm),\nO2 (3–7c m )o rO 3( >7c m )( ▶ Video 33, ▶ Fig. 7) [16].\nIn a situs with one or more endometriomas, a careful and\ncomprehensive evaluation should include the search for im-\npaired sliding as an indication of adhesions and DE. Mobility ter-\nminology is not yet uniform ( ▶ Video 19). The ovaries are slight-\nly pushed cranially by gently applying axial or paraxial pressure\n(▶ Video 34 ). If the ovaries do not slide against the pelvic side-\nwall, the broad ligament, or the surrounding bowels, lateral ad-\nhesions must be considered (#ENZIAN T1) ( ▶ Video 35 ). In our\nexperience, it is less challenging to demonstrate free or impaired\nsliding against the medial structures (uterus, vagina). The tubal-\novarian complex with the indication of adhesions to the uterus is\nclassified as #ENZIAN T2. Additional adhesions to the bowel or\nSULs are classified as #ENZIAN T3, leading to a moving block\n(block sign )( ▶ Video 32, ▶ Fig. 7)[ 1 6 ] .\nThe kissing ovaries sign describes both ovaries (with or without\nendometriomas) fixed together behind the uterus in the POD\n(▶ Video 36). Pushing the probe between them does not separate\nthem but probably causes pain, leading to the conclusion of a high\nprobability of adhesions corresponding to #ENZIAN T3. This is par-\nticularly important for preoperative planning [32] since intestinal\ninvolvement is more likely in patients with kissing ovaries than in\nthose with other endometriosis manifestations [32].\nOP-VIDEO\n▶ Video 28 Rectal DE lesion. Indian headdress sign or moose antler\nsign. Full thickness defect. #ENZIAN: C2.\n2 central\n3\nposterior\n1 anterior\n4 + 5 lateral\n▶ Fig. 15 Lateral compartments. Image on the right: adapted from Schünke M, Schulte E, Schumacher U, Voll M, Wesker K. 6.23 Schnittbildana-\ntomie des weiblichen Beckens. In: Schünke M, Schulte E, Schumacher U, Voll M , Wesker K, Hrsg. Prometheus LernAtlas – Innere Organe. 5. Auflage.\nStuttgart: Thieme; 2018. doi:10.1055/b-006 –149 645.\n383Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\nOP-VIDEO\n▶ Video 29 Lateral compartment\nOP-VIDEO\n▶ Video 30 Right tail sign\nOP-VIDEO\n▶ Video 31 Left tail sign\nOP-VIDEO\n▶ Video 32 Block sign. «Moving block» involving vaginal wall, SUL,\novary, bowel. #ENZIAN: A2 B3/0 T3/0.\nOP-VIDEO\n▶ Video 33 Endometrioma. «Moving block» involving vaginal wall,\nSUL, ovary, bowel. #ENZIAN: A2 B3/0 T3/0.\nOP-VIDEO\n▶ Video 34 Completely free ovarian sliding\n384 Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nGuidelines & Recommendations\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\nOP-VIDEO\n▶ Video 39 Right CAL presentation. CAL: cardinal ligament\nOP-VIDEO\n▶ Video 37 Chronic sactosalpinx\nOP-VIDEO\n▶ Video 38 Swashing pseudoperitoneal cyst\nOP-VIDEO\n▶ Video 35 Impaired ovarian sliding\nOP-VIDEO\n▶ Video 36 Kissing ovaries sign. Fixed ovaries in “kissing position ”\nbehind the uterus, the so-called “kissing ovaries sign ”,a ne x a m p l e\nof the “block sign ”\nOP-VIDEO\n▶ Video 40 Left CAL presentation. CAL: cardinal ligament\n385Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\n4.4.4 Fallopian tubes\nThe Fallopian tubes are only visible on TVS if contrasted from in-\nside or outside by a physiological or pathological collection of li-\nquid. Endometriosis may cause hemato- or hydrosalpinges [17]\n(▶ Video 37) and peritoneal cysts [8], sometimes showing typical\nswashing sails (▶ Video 38 ). Chronic sactosalpinx carries the pa-\nthognomonic signs of incomplete septa or the cogwheel sign [33].\n4.4.5 Broad ligaments and pelvic sidewall\nDynamic investigation of the adnexal region, provoking sliding of\nbowels and ovaries along the omega sign, should demonstrate the\nfree sliding between these organs, to the dorsal sheet of the\nbroad ligaments, and the pelvic sidewalls ( ▶ Video 30, 31). Inves-\ntigators should notice reduced or absent sliding, which can be\nclassified for each side as #ENZIAN T1 (adhesions of adnexa to pel-\nvic sidewall), T2 (T1 and adhesions to uterus), or T3 (T2 and adhe-\nsions to SULs or bowel). DE lesions appear mainly near the cervix\n(#ENZIAN B) ( ▶ Fig. 7) [16].\n4.4.6 Cardinal ligaments (CAL)\nOn TVS, the CALs become visible under an appropriate push as the\nechogenic, longish structure several centimeters in length at the\ncaudal end of the broad ligament , containing the UVC with the\nuterine artery and many veins ( ▶ Video 39–41). They may be con-\nveniently found when looking for the tail sign (dorsal sheet of the\nbroad ligament) from the lateral fornix in a transverse plane run-\nning nearly horizontally through the right or left lateral compart-\nment at the lower uterine corpus ( ▶ Video 41). They run from the\nlower lateral corpus, cervix, and vaginal fornix to the pelvic side-\nwall, whereby both borders fade into the neighboring structures.\nAt the caudal end, the CALs connect directly to the SULs.\nThe ureters are the second leading structures in the CALs.\nThey cross the CALs by passing under the UVC in a more or less\nstraight course laterodorsally ( ▶ Video 42).\nOP-VIDEO\n▶ Video 43 Right SUL presentation. CAL: cardinal ligament,\nSUL: sacrouterine ligament\nOP-VIDEO\n▶ Video 41 CAL and SUL presentation. CAL: cardinal ligament;\nPOD: pouch of Douglas; SUL: sacrouterine ligament; UTA: uterine\nartery; UVC: uterovascular complex. Image top right: adapted from\nSchünke M, Schulte E, Schumacher U, Voll M, Wesker K. 6.23\nSchnittbildanatomie des weiblichen Beckens. In: Schünke M,\nSchulte E, Schumacher U, Voll M, Wesker K, Hrsg. Prometheus\nLernAtlas – Innere Organe. 5. Auflage. Stuttgart: Thieme; 2018.\ndoi:10.1055/b-006 –149 645\nOP-VIDEO\n▶ Video 42 CAL, ureter, UVC. CAL: cardinal ligament; UTA: uterine\nartery; UVC: utero-vascular complex\nOP-VIDEO\n▶ Video 44 Left SUL presentation. CAL: cardinal ligament,\nSUL: sacrouterine ligament\n386 Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nGuidelines & Recommendations\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.\n\n\nLesions in this area should also be measured in their maxi-\nmum lateral extent and assigned to #ENZIAN B separately for\nleft and right (B1: < 1 cm, B2: 1 –2 cm, B3: > 3 cm) ( ▶ Fig. 7)[ 1 6 ] .\n4.4.7 Sacrouterine ligaments (SULs)\nThe SULs are preferably found topographically and not morpholo-\ngically [14]. In a transverse plane, they directly connect caudally\nto the CALs as a bright, echogenic stripe in the dorsal peritoneum\nthat extends laterally from the cervix. The probe should be rota-\nted outwardly and downwardly to follow the SULs towards the\npelvic sidewall ( ▶ Video 43, 44 ). If correctly exposed, the SULs\nwill wrap around the tip of the TVS probe.\nThe SULs are the favored site of DE and harbor 53 % of DE\nlesions [15]. They should be considered affected if the retrocervi-\ncal sliding mobility is impaired, a hypoechogenic thickening inter-\nrupts its hyperechoic presentation, or a substantial DE lesion\naffects one or both SULs or the torus in-between ( ▶ Video 45 ).\nLesions may be isolated or multiple, affecting the vaginal wall,\nt h eo v a r i e s ,t h eb o w e l ,t h eu r e t e r s ,o rs o m ec o m b i n a t i o nt h e r e o f\n(▶ Video 32 ) [8]. An advantage of using the transverse plane is\nthe comparability of the right and left SULs and the inspection of\nthe torus at a glance ( ▶ Video 45).\nAs with CAL lesions, SUL lesions are measured in the largest\ndiameter and subsequently classified as side-separated according\nto #ENZIAN B (left/right). Note that central lesions on the torus,\naffecting the retrocervical area, have to be assigned to #ENZIAN A\n(▶ Fig. 7) [16].\n5S u m m a r y\nToday, TVS is the primary diagnostic tool for suspected endo-\nmetriosis, e. g., due to its cost-effectiveness, direct applicability\nby gynecologists, and excellent imaging quality. Although TVS is\ngenerally well tolerated, its dynamic application is mandatory for\ndetecting sliding disorders and endometriotic lesions. Still, it\nrequires specific expertise and poses a challenge for training at\ndifferent levels.\nThis paper presents a practical, systematic, comprehensive,\nchecklist-based sonographic approach for diagnosing pelvic\nendometriosis in five well-defi ned compartments. It includes\ndetailed explanations, diagrams, and ultrasound videos based on\nIDEA 2016. It directly links the #ENZIAN classification, resulting in\ncomparability across cases, imaging modalities, and disciplines.\nConflict of Interest\nJulian Metzler: Founder of Scanvio Medical AG.\nMichael Bajka: Founder of Scanvio Medical AG.\nReferences\n[1] Keckstein J, Hoopmann M. Endometriosis, ultrasound and #Enzian clas-\nsification: the need for a common language for non-invasive diagnostics.\nUltraschall Med 2023; 44: 233 –239. doi:10.1055/a-2055-6712\n[2] Piketty M, Chopin N, Dousset B et al. Preoperative work-up for patients\nwith deeply infiltrating endometriosis: transvaginal ultrasonography\nmust definitely be the first-line imaging examination. Human reproduc-\ntion (Oxford, England) 2009; 24: 602 –607. doi:10.1093/humrep/\nden405\n[3] Keckstein J, Hoopmann M, Merz E et al. Expert opinion on the use of\ntransvaginal sonography for presurgical staging and classification of\nendometriosis. Archives of Gynecology and Obstetrics 2022; 307: 5 –19.\ndoi:10.1007/s00404-022-06766-z\n[4] Montanari E, Bokor A, Szabo G et al. Accuracy of sonography for non-in-\nvasive detection of ovarian and deep endometriosis using #Enzian clas-\nsification: prospective multicenter diagnostic accuracy study. Ultra-\nsound Obstet Gynecol 2022; 59: 385 –391. doi:10.1002/uog.24833\n[5] Van Holsbeke C, Van Calster B, Guerriero S et al. Endometriomas: their\nultrasound characteristics. Ultrasound in Obstetrics and Gynecology\n2010; 35: 730 –740. doi:10.1002/uog.7668\n[6] Harmsen MJ, Van den Bosch T, de Leeuw RA et al. Consensus on revised\ndefinitions of Morphological Uterus Sonographic Assessment (MUSA)\nfeatures of adenomyosis: results of modified Delphi procedure. Ultra-\nsound in Obstetrics & Gynecology 2022; 60: 118 –131. doi:10.1002/\nuog.24786\n[7] Krentel H, Keckstein J, Fuger T et al. 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J Minim Invasive Gynecol 2018; 25:\n884–891. doi:10.1016/j.jmig.2017.12.026\n[32] Ghezzi F, Raio L, Cromi A et al. “Kissing ovaries ”:As o n o g r a p h i cs i g n\nof moderate to severe endometriosis. Fertility and Sterility 2005; 83:\n143–147. doi:10.1016/j.fertnstert.2004.05.094\n[33] Timor-Tritsch IE, Lerner JP, Monteagudo A et al. Transvaginal sono-\ngraphic markers of tubal inflammatory disease. Ultrasound Obstet\nGynecol 1998; 12: 56 –66. doi:10.1046/j.1469-0705.1998.12010056.x\n388 Metzler JM et al. Systematic, noninvasive endometriosis … Ultraschall in Med 2024; 45: 367 –388 | © 2024. Thieme. All rights reserved.\nGuidelines & Recommendations\nThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.","source_license":"CC0","license_restricted":false}