{"paper_id":"7fa95ec2-029f-45d6-90d4-1b10e81191b4","body_text":"Original Study/Estudo Original \n268 Acta Obstet Ginecol Port 2025;19(4):268-279 \nAbstract \nObjective: To provide estimates of the diagnostic accuracy of transvaginal ultrasound, sonovaginography and magnetic re -\nsonance imaging for the diagnosis of ovarian endometriosis and deep endometriosis. \nMethods: This was an observational, retrospective study carried out in a Portuguese tertiary center. Consecutive patients who \nunderwent surgical procedures between 2010 and 2023 for diagnosis and treatment of endometriosis were included. The in -\ndex tests were transvaginal ultrasound, sonovaginography and magnetic resonance imaging. Accuracy of these tests to iden -\ntify lesions of endometriosis was assessed for different sites, relative to surgical findings. Data was obtained from imaging and \nsurgical reports. Sensitivity , specificity , positive and negative predictive values were calculated for each diagnostic method. \nResults: Out of 301 patients who underwent surgery , 195 (64.8%) were evaluated with transvaginal ultrasound, 99 (32.9%) \nhad a sonovaginography performed and 167 (55.5%) were evaluated with magnetic resonance imaging. All but 3 (1.0%) \npatients had endometriosis confirmed through surgical visualization. The sensitivity and specificity for ovarian endome -\ntriosis were 95.2% and 83.1% for transvaginal ultrasound and 91.0% and 80.5% for magnetic resonance imaging, respec -\ntively . Regarding deep endometriosis, the sensitivity and specificity were 84.1% and 54.5% for sonovaginography and \n90.3% and 60.0% for magnetic resonance imaging, respectively . \nConclusion: Transvaginal ultrasound was highly accurate for the diagnosis of endometriomas and, when used alongside so -\nnovaginography it had important value in the diagnosis of deep endometriosis as well. Both sonovaginography and magne -\ntic resonance imaging showed similar performance in diagnosing deep endometriosis and stand as reliable diagnostic tools. \nKeywords: Endometriosis; Diagnosis; Diagnostic imaging; Ultrasonography; Magnetic Resonance Imaging. \nEndometriosis diagnosis: a retrospective study on the use of \ntransvaginal ultrasound, sonovaginography and magnetic \nresonance imaging \nDiagnóstico de Endometriose: uma análise retrospetiva do uso de \necografia transvaginal, sonovaginografia e ressonância magnética \npélvica \nEva Maria de Jesus Paiva 1, Ana Mafalda da Costa Castro Neves 2, Pedro Viana Pinto 3, Ana Margarida Póvoa 4, Andreia T eixeira 5\nFaculdade de Medicina da Universidade do Porto \nCentro Hospitalar Universitário de São João \nResumo \nObjetivo: Obter estimativas da capacidade diagnóstica da ecografia transvaginal, sonovaginografia e ressonância magné -\ntica para o diagnóstico de endometriose ovárica e profunda. \nMétodos: Este foi um estudo observacional retrospetivo que decorreu num centro terciário português. Foram incluídos \npacientes sujeitos a procedimentos cirúrgicos para o diagnóstico e tratamento de endometriose entre 2010 e 2023. A ca -\npacidade da ecografia transvaginal, sonovaginografia e ressonância magnética para a identificação de lesões de endome -\ntriose foi avaliada para diferentes localizações, tendo por referência os achados cirúrgicos. Os dados foram obtidos a partir \ndos relatos imagiológicos e cirúrgicos. Para cada método diagnóstico foram calculadas as seguintes medidas: sensibilida -\nde, especificidade, valores preditivos positivos e negativos. \nDOI: 10.69729/aogp.v19i4a05 \n\nEva Maria de Jesus Paiva et al. \nActa Obstet Ginecol Port 2025;19(4):268-279 269 \nINTRODUCTION \nE\nndometriosis is a chronic disease characterized by \nthe presence of endometrium-like tissue outside \nthe endometrium, frequently accompanied by an asso- \nciated inflammatory reaction 1. The exact prevalence of \nthis disease is unknown, but it is thought to affect \naround 10% of women in their reproductive years 2.\nEndometriosis manifests mainly as three different \nsubtypes: superficial implants in the peritoneum, ova -\nrian endometriosis (endometriomas) and deep-seated \ninfiltration into nearby tissues and pelvic organs (deep \ninfiltrating endometriosis, DE). According to an inter -\nnational working group, DE is defined as “endome -\ntrium-like tissue lesions in the abdomen, extending on \nor under the peritoneal surface; they are usually nodu -\nlar, able to invade adjacent structures, and associated \nwith fibrosis and disruption of normal anatomy” 1. The -\nse subtypes may differ in symptom presentation and \ndiagnostic approach 1,3 . The clinical manifestations ran -\nge from dysmenorrhea and deep dyspareunia to dysu -\nria, dyschezia and infertility 4. No symptom is specific \nor pathognomonic of endometriosis and its severity \ndoes not correlate to the surgical stage of the disease, \nwhich can remain undiagnosed for 8 to 12 years 5. This \ndelay leads to long- lasting pain, reduced quality of life, \npsychological stress, and compromised fertility 6.\nDiagnosing endometriosis remains a challenge for \nclinicians 7. Laparoscopic observation and biopsy are \nconsidered the gold standard for the diagnosis although \nidentifiable lesions may not always be histologically \nconfirmed 4,5 . Physical examination alone has low diag -\nnostic accuracy , so imaging is widely used to establish \na diagnosis and evaluate the extent of the disease as \nsurgery is invasive and costly 3,4 . Surgical intervention \nis usually reserved for women with disease non-res -\nponsive to medical treatment, infertility and severe di -\nsease (interfering with organ function) so noninvasive \nimaging exams assume a preponderant role 6.\nTransvaginal ultrasonography (TVUS) allows for real- \n-time assessment of the uterus, adnexa and surrounding \nstructures while granting dynamic evaluation of organ mo -\nbility hence it is the first- line imaging modality to use when \nsuspecting of endometriosis 8-10 . TVUS detection is greatly \ndependent on the experience of the operator and the lo -\ncation of the endometriotic lesions, being especially use -\nful in patients with endometriomas or DE 9,11,12 . Sonovagi -\nnography (SVG), introduced by Dessole et al in 2003, is a \nResultados: De 301 doentes submetidos a cirurgia, 195 (64,8%) realizaram ecografia transvaginal, 99 (32,9%) efetuaram \nsonovaginografia e 167 (55,5%) foram avaliados com ressonância magnética. O diagnóstico de endometriose foi confir -\nmado, através de visualização direta, em todos os pacientes exceto 3 (1,0%). A sensibilidade e especificidade da ecografia \ntransvaginal para o diagnóstico de endometriose ovárica foram 95,2% e 83,1% e da ressonância magnética foram 91,0% e \n80,5%, respetivamente. Relativamente ao diagnóstico de endometriose profunda, obtivemos sensibilidade e especificida -\nde de 84,1% e 54,5% para a sonovaginografia e de 90,3% e 60,0% para a ressonância magnética, respetivamente. \nConclusão: A ecografia transvaginal apresentou um desempenho excelente no diagnóstico de endometriomas e, quando \nusada em conjunto com a sonovaginografia, revelou grande valor para o diagnóstico de endometriose profunda. Tanto a \nsonovaginografia como a ressonância magnética obtiveram resultados semelhantes para o diagnóstico de endometriose \nprofunda e afirmam-se como métodos de imagem confiáveis. \nPalavras-chave: Endometriose; Diagnóstico; Imagiologia diagnóstica; Ultrassonografia; Imagem de Ressonância Magnética. \n1. Faculdade de Medicina, Universidade do Porto, Porto, Portugal. \n2. Department of Obstetrics and Gynecology , Centro Hospitalar Universitário de São João, Porto, Portugal. \n3. Department of Obstetrics and Gynecology , Centro Hospitalar Universitário de São João, Porto, Portugal; Department of Anatomy , Faculdade de Medi -\ncina, Universidade do Porto, Porto, Portugal; Department of Obstetrics and Gynecology , Faculdade de Medicina, Universidade do Porto, Porto, Portugal. \n4. Department of Obstetrics and Gynecology , Centro Hospitalar Universitário de São João, Porto, Portugal; Department of Obstetrics and Gynecology , Fa -\nculdade de Medicina, Universidade do Porto, Porto, Portugal. \n5. MEDCIDS – Department of Community Medicine, Information and Decision in Health; Faculdade de Medicina, Universidade do Porto, Porto, Portu -\ngal; CINTESIS@RISE – Center for Health Technology and Services Research; Faculdade de Medicina, Universidade do Porto, Porto, Portugal; ADiT-LAB, \nInstituto Politécnico de Viana do Castelo. \n\nEndometriosis diagnosis: a retrospective study on the use of transvaginal ultrasound, sonovaginography and magnetic resonance imaging \n270 Acta Obstet Ginecol Port 2025;19(4):268-279 \ncontrast-enhanced transvaginal ultrasound using saline \nsolution or gel to create an acoustic window between the \nprobe and surrounding structures. It is used as an addi -\ntional tool to identify and characterize DE 9,13-15 . Magnetic \nresonance imaging (MRI) is recommended as a further step \nin the diagnostic workup of endometriosis following an \nequivocal ultrasonography evaluation and in case of ex -\ntensive disease 16 . Infiltrating lesions are more precisely \nmapped as it has a larger field of view and high tolerabili -\nty therefore significantly helping preoperative planning 9.\nThe high accuracy of such non-invasive modalities \nguarantees their use as standard, enabling early diag -\nnosis which in turn facilitates medical treatment and \nensures optimal planning for adequate surgical mana -\ngement, anticipating its difficulty and helping deter -\nmine when a multidisciplinary team is needed 7,17 .\nIn this study , we aim to provide estimates of the diag -\nnostic accuracy of these non-invasive imaging methods \nfor the diagnosis of endometriomas and deep endo -\nmetriosis in patients who had surgical procedures in a \ntertiary referral center and to compare the performan -\nce of these modalities in accurately mapping lesions \nand assessing their extent. \nMETHODS \nThis was an observational, retrospective cohort study \ncarried out in a tertiary center in Portugal and com -\npliant with the STARD (Standards for Reporting of \nDiagnostic Accuracy) guidelines. The study was \napproved by the local ethics committee. All patients \nwho underwent surgical procedures (laparoscopy or \nlaparotomy) for diagnosis and treatment of endome -\ntriosis between 2010 and 2023 were eligible for inclu -\nsion and we reviewed the unit’s surgical database to se -\nlect them. These patients were followed in this hospi -\ntal and had clinical or imaging suspicion of ovarian or \ndeep endometriosis. We excluded those who had ex -\ntrapelvic endometriosis or adenomyosis alone. \nThe archived data about clinical history , transvagi -\nnal ultrasound, sonovaginography , magnetic resonan -\nce imaging and surgery results were collected from elec -\ntronic medical records (SClinico and BHealth). \nThe topography of the endometriotic lesions was ob -\ntained from imaging and surgical reports regarding an -\nterior compartment involvement (distal ureters and \nbladder), posterior compartment involvement (utero -\nsacral ligaments; uterine torus, rectovaginal septum \nand posterior vaginal wall), intestinal involvement (rec -\ntum, sigmoid and rectosigmoid transition), and pre -\nsence of ovarian endometriomas. For each location, \ndata were classified as positive or negative for the de -\ntection of endometriosis in every test. \nFor every patient, the following anamnestic data were \ncollected: age, height and weight, smoking status, age \nat menarche, parity and gravidity , history of previous \nsurgeries and medical conditions. Clinical symptoms of \nendometriosis such as dysmenorrhea, dyspareunia or \ninfertility were also documented as well as if the patient \nwas referred due to an incidental imaging finding. \nAs per this study’s retrospective methodology , all \nthose performing imaging studies or surgery had \naccess to clinical information regarding the patient at \nthe time of execution of the respective procedures. Pa -\ntients underwent each imaging exam as their assistant \ngynecologist saw appropriate, considering each case. \nAll reports were analyzed, and the relevant findings \nwere adequately noted. Some reports did not provide \ninformation on endometriosis findings regarding eve -\nry topographic location considered in this study . In tho -\nse cases, we retrieved the available information and \nmissing results for each location were excluded from \nthe analysis. When the report expressed uncertainty \nregarding the presence of endometriosis in a given lo -\ncation, we considered it a positive finding. \nTransvaginal ultrasound and sonovaginography \nTransvaginal ultrasound and sonovaginography were \nmostly performed in the gynecology department by the \nsame two gynecologists, with extensive expertise in US \ndiagnosis of endometriosis; only a minority of patients \nhad an US executed by their doctor within the clinical \nappointment. During the first years of the study, a \nVoluson™ 730 (General Electric, USA) transvaginal \n5-9 MHz probe was used; from 2021 a Voluson™ S8 \n(General Electric, USA) was used. No bowel preparation \nwas used before sonography or sonovaginography . \nSonographic assessment was routinely done accor -\nding to IDEA group consensus since its publication 11 .\nAnatomic sites in the anterior and posterior com- \npartments were evaluated for possible endometriotic \n\nEva Maria de Jesus Paiva et al. \nActa Obstet Ginecol Port 2025;19(4):268-279 271 \nfindings like a hypoechoic thickening, hypoechoic \nirregular nodules, pouch of Douglas obliteration and \npelvic adhesions. Obliteration of the vesicouterine or \nrectovaginal pouches was assessed by gently pressing \nthe uterus with the probe (anterior and posterior sli -\nding signs). Endometriomas were described according \nto the International Ovarian T umor Analysis (IOTA) \nterminology and typically appear on ultrasound as uni -\nlocular, round and with regular margins, fluid-filled \ncysts with ground glass homogeneous echogenicity (Fi -\ngure 1A) but can also have atypical features like multi -\nple locules and papillations 18 . DE lesions in the anterior \ncompartment were diagnosed when finding hypoe -\nchoic lesions extending farther than the bladder sero -\nsa or ureter strictures. In the posterior compartment, \nDE was identified when observing hypoechoic solid \nnodules with heterogeneous size and margins or hy -\npoechoic thickening of the vagina or intestinal wall (Fi -\ngure 1B). \nSonovaginography was performed when clinicians \ndeemed it appropriate to better characterize DE lesions. \nAcoustic window was obtained by placing 50 ml of ul -\ntrasound gel in the vagina to distend its walls and \nenhance visualization of the vaginal walls and fornix, \nuterosacral ligaments, pouch of Douglas and rectova -\nginal septum. Each examination also included a tran -\nsabdominal ultrasound with the bladder filled in order \nto better evaluate the presence of any relevant lesion. \nMagnetic resonance imaging \nPelvic MRI was performed as per hospital protocol, \nusing hyoscine butylbromide to reduce intestinal pe -\nristalsis and contrast if suspecting of an atypical endo -\nmetrioma in order to exclude potential malignancy . Pa -\ntients did not undergo any bowel preparation. The pro -\ntocol also included administration of sterile vaginal ul -\ntrasound gel. The majority of the exams were \nperformed using a Siemens MAGNETOM Vida™ de -\nvice. A minority of the patients had MRI reports from \nexternal facilities, but these cases were discussed in \ngroup meetings before surgery . From 2020 all cases \nwere reviewed by a multidisciplinary specialized group, \nincluding radiologists specialized in pelvic imaging and \ngynecologists with both ultrasound and surgical expe -\nrience in dealing with endometriosis. \nDE can be detected on MRI by an array of findings ran -\nging from ectopic endometrial nodules to thickened struc -\ntures, fibrosis or changes to the usual pelvic anatomy; \nFIGURE 1. Imaging findings of endometriosis. \n\nEndometriosis diagnosis: a retrospective study on the use of transvaginal ultrasound, sonovaginography and magnetic resonance imaging \n272 Acta Obstet Ginecol Port 2025;19(4):268-279 \nthe implants typically appear as hyperintense areas foci on \nT1 with fat suppression and hypointense in T2-weighted \nMR images on the respective locations (Figure 1C). Fur- \nthermore, obliteration of pelvic pouches, disappearance \nof fat tissue planes and ureteral dilation are also signs of \nthe disease. Endometriomas were diagnosed as hyperin -\ntense ovarian cysts on T1-weighted images and hypoin -\ntense on T2W (Figure 1D). \nSurgery \nAll surgical interventions were performed in this hospital \nby a skilled set of gynecologists, with experience in ad -\nvanced laparoscopic surgery . This was considered the re -\nference standard for the analysis as it is still considered the \ngold standard for the diagnosis of endometriosis 5. Diag -\nnosis of DE was made when at least one of the above-men -\ntioned structures was involved; the location of all suspi -\ncious lesions was recorded and removed for histological \nconfirmation. T ypical lesions like dark “powder-burn” no -\ndules, implants or cysts with thick content were visually \nidentified on the pelvic structures and considered as DE \nwhen extending > 5 mm beneath the peritoneum. Spicu -\nlated nodules and thickening of pelvic structures were also \nevaluated for the presence of the disease. Ovarian endo -\nmetriomas were identified as blood-filed cysts often ad -\nherent to the uterus or surrounding ligaments. \nStatistical analysis \nStatistical analysis was performed using SPSS version 29. \nFor each diagnostic tool, the sensitivity , specificity , posi -\ntive predictive value and negative predictive value with \ntheir respective 95% confidence interval were calculated \nfor individual and grouped locations. We performed a se -\ncondary analysis of diagnostic accuracy , calculating sen -\nsitivity and specificity in the group of patients who un -\nderwent TVUS complemented with SVG; TVUS versus \nMRI for endometrioma diagnosis and SVG versus MRI \nfor DE detection. To compare the diagnostic perfor -\nmance of these methods, the McNemar’s test was used \nand a p value <0.05 was considered significant. \nRESULTS \nTable I presents the demographic data of our population \nas well as their clinical symptoms and surgical findings. \nIn total, 301 patients were submitted to surgery due to en -\ndometriosis and were included in the analysis. The mean \nage of our patients was 36.6 years (range 18-61) with a \nmedian BMI of 23.9 Kg/m 2. We found dysmenorrhea to \nbe the most common symptom of our patients (69.0%), \nfollowed by deep dyspareunia (44.9%). At least 64 pa -\ntients (22.9%) had infertility and 40 (13.3%) had un -\ndergone previous endometriosis surgery . \nRegarding surgeries performed, 285 (94.7%) patients \nhad laparoscopic surgery while the remaining 16 (5.3%) \nhad a laparotomy performed. All but 3 (1.0%) patients \nhad endometriosis confirmed through surgical visuali -\nzation. Based on surgical records, we found that 180 \n(59.8%) patients had endometriomas and 207 (68.8%) \nDE. Both subtypes were present in 90 (29.9%) patients. \nRegarding temporal trends, 25.2% of surgeries were \nperformed between 2010 and 2014, 35.2% between \n2015 and 2019, and 39.5% between 2020 and 2023. \nTransvaginal ultrasound \nOut of the 301 patients included in this study , 195 \n(64.8%) were evaluated with TVUS. The diagnostic per -\nformance of TVUS in predicting endometriosis in dis -\ntinct locations is presented in Table II. Regarding ovarian \nendometriosis, the sensitivity of TVUS for endometrio -\nmas was 95.2% (120/126) (95% CI 91.5-99.0) with spe -\ncificity of 83.1% (49/59) (95% CI 73.5-92.6); however, \nregarding DE (both anterior and posterior compartment \nlesions), only 24 out of 124 patients with surgical fin -\ndings of DE were correctly diagnosed. \nSonovaginography \nA total of 99 (32.9%) patients had an SVG performed, \nand its diagnostic performance is reported in Table II. \nRegarding overall DE, SVG correctly identified 74 out of \n88 patients who had DE diagnosed during surgery . In \nthe anterior compartment, SVG missed DE in 18 patients \nwhich resulted in a sensitivity of 14.3% (3/21) (95% \nCI 0.0-29.3); however, for the posterior compartment, \nthe overall sensitivity was 83.9% (73/87) (95% CI \n76.2-91.6). In this compartment, diagnostic sensitivity \nof endometriosis was highest for uterine torus, rectova -\nginal septum and posterior vaginal wall at 73.6% (53/72) \n(95% CI 63.4-83.8) compared to uterosacral ligaments \n(37.1% (26/70); 95% CI 25.8-48.5) and intestinal \nendometriosis (36.4% (16/44); 95% CI 22.2-50.6). \n\nEva Maria de Jesus Paiva et al. \nActa Obstet Ginecol Port 2025;19(4):268-279 273 \nComparison of TVUS and SVG – SVG as a \ncomplement of TVUS \nSVG was used as a complement of TVUS when sus -\npecting DE, as was considered pertinent. For that rea -\nson, out of 99 patients who performed gel SVG, 94 also \nhad available records of TVUS. In this smaller group, \nwe compared the diagnostic performance of both ul -\ntrasound techniques separately and considering their \nfindings together, as that is more resembling of what \nhappens in clinical practice. Our results can be found \nin Table III. TVUS alone was more sensitive for endo -\nmetrioma detection reaching a sensitivity of 95.7% \n(44/46) (95% CI 89.8-100) and specificity of 91.3% \n(42/46) (95% CI 83.2-99.5) while SVG alone was more \nsensitive for the diagnosis of DE achieving a sensitivi -\nty of 83.1% (69/83) (95% CI 75.1-91.2) and specifici -\nty of 54.5% (6/11) (95% CI 25.1-84.0). \nMagnetic resonance imaging \nAmongst our population, 167 (55.5%) patients were \nevaluated with MRI. The diagnostic performance of this \nimaging study in diagnosing endometriosis in specific \npelvic locations is reported in Table IV . For endome -\ntrioma detection, MRI showed a sensitivity of 91.0% \n(61/67) (95% CI 84.2-97.9) and specificity of 80.5% \n(62/77) (95% CI 71.7-89.4); for DE, MRI correctly \nTABLE I. DEMOGRAPHIC CHARACTERISTICS, CLINICAL SYMPTOMS AND SURGICAL FINDINGS. \nPatient characteristics N=301 \nAge, years, M (SD) 36.6 (6.5) \nWeight (N=236), Kg, Med [Q1;Q3] 63.0 [56.0;71.0] \nHeight (N=188), m, Med [Q1;Q3] 1.63 [1.60;1.67] \nBMI (N=178), Kg/m 2, Med [Q1;Q3] 23.9 [21.2;26.6] \nAge at menarche (N=195), years, M (SD) 12.2 (1.7) \nGravidity (N=279), Med [Q1;Q3] 1 [0;2] \nParity (N=279), Med [Q1;Q3] 0 [0;1] \nSmokers (N=146), n (%) 28 (19.2) \nSymptoms \nDysmenorrhea (N=274), n (%) 189 (69.0) \nDeep dyspareunia (N=274), n (%) 123 (44.9) \nInfertility (N=279), n (%) 64 (22.9) \nPrevious endometriosis surgery, n (%) 40 (13.3) \nPrevious abdominal/pelvic surgery (n=281), n (%) 127 (45.2) \nSurgical findings \nOvarian endometriosis, n (%) 180 (59.8) \nRight, n (%) 56 (18.6) \nLeft, n (%) 75 (24.9) \nBilateral, n (%) 49 (16.3) \nDeep endometriosis, n (%) 207 (68.8) \nAnterior compartment, n (%) 52 (17.3) \nBladder, n (%) 35 (11.6) \nUreters, n (%) 19 (6.3) \nPosterior compartment, n (%) 198 (65.8) \nUterosacral ligaments, n (%) 150 (49.8) \nUterine torus, rectovaginal septum and posterior vaginal wall, n (%) 158 (52.5) \nBowel, n (%) 99 (32.9) \nRectum, n (%) 84 (27.9) \nRectosigmoid transition, n (%) 7 (2.3) \nSigmoid colon, n (%) 29 (9.6) \nBMI: body mass index \n\nEndometriosis diagnosis: a retrospective study on the use of transvaginal ultrasound, sonovaginography and magnetic resonance imaging \n274 Acta Obstet Ginecol Port 2025;19(4):268-279 \nTABLE II. DIAGNOSTIC PERFORMANCE OF TRANSVAGINAL ULTRASOUND AND SONOVAGINOGRAPHY FOR PREOPERATIVE DIAGNOSIS OF ENDOMETRIOSIS. \nSensitivity Specificity PPV NPV Accuracy \nSite TP (n) FP (n) TN (n) FN (n) N (95% CI) (95% CI) (95% CI) (95% CI) (95% CI) \n(%) (%) (%) (%) (%) \nTVUS \nOvarian endometriosis 120 10 49 6 185 95.2 83.1 92.3 89.1 91.4 \n(91.5-99.0) (73.5-92.6) (87.7-96.9) (80.9-97.3) (87.3-95.4) \nDeep endometriosis 24 1 38 100 163 19.4 97.4 96.0 27.5 38.0 \n(12.4-26.3) (92.5-100) (88.3-100) (20.1-35.0) (30.6-45.5) \nAnterior compartment 4 1 122 23 150 14.8 99.2 80.0 84.1 84.0 \n(1.4-28.2) (97.6-100) (44.9-100) (78.2-90.1) (78.1-89.9) \nBladder 3 1 128 17 149 15.0 99.2 75.0 88.3 87.9 \n(0.0-30.7) (97.7-100) (32.6-100) (83.0-93.5) (82.7-93.2) \nUreters 1 1 137 7 146 12.5 99.3 50.0 95.1 94.5 \n(0.0-35.4) (97.9-100) (0.0-100) (91.6-98.7) (90.8-98.2) \nPosterior compartment 23 1 44 95 163 19.5 97.8 95.8 31.7 41.1 \n(12.3-26.6) (93.5-100) (87.8-100) (23.9-39.4) (33.6-48.7) \nUterosacral ligaments 11 0 62 82 155 11.8 100 100 43.1 47.1 \n(5.3-18.4) (100-100) (100-100) (35.0-51.1) (39.2-55.0) \nUterine torus, rectovaginal septum 17 3 62 75 157 18.5 95.4 85.0 45.3 50.3 \nand posterior vaginal wall (10.6-26.4) (90.3-100) (69.4-100) (36.9-53.6) (42.5-58.1) \nBowel 6 1 99 48 154 11.1 99.0 85.7 67.3 68.2 \n(2.7-19.5) (97.1-100) (59.8-100) (59.8-74.9) (60.8-75.5) \nSVG \nDeep endometriosis 74 5 6 14 99 84.1 54.5 93.7 30.0 80.8 \n(76.5-91.7) (25.1-84.0) (88.3-99.0) (9.9-50.1) (73.1-88.6) \nAnterior compartment 3 3 73 18 97 14.3 96.1 50.0 80.2 78.4 \n(0.0-29.3) (91.7-100) (10.0-90.0) (72.0-88.4) (70.2-86.6) \nBladder 2 3 78 13 96 13.3 96.3 40.0 85.7 83.3 \n(0.0-30.5) (92.2-100) (0.0-82.9) (78.5-92.9) (75.9-90.8) \nUreters 0 2 85 7 94 0.0 97.7 0.0 92.4 90.4 \n(0.0-0.0) (94.6-100) (0.0-0.0) (87.0-97.8) (84.5-96.4) \nPosterior compartment 73 6 6 14 99 83.9 50.0 92.4 30.0 79.8 \n(76.2-91.6) (21.7-78.3) (86.6-98.3) (9.9-50.1) (71.9-87.7) \nUterosacral ligaments 26 6 19 44 95 37.1 76.0 81.3 30.2 47.4 \n(25.8-48.5) (59.3-92.7) (67.7-94.8) (18.8-41.5) (37.3-57.4) \nUterine torus, rectovaginal septum 53 15 10 19 97 73.6 40.0 77.9 34.5 64.9 \nand posterior vaginal wall (63.4-83.8) (20.8-59.2) (68.1-87.8) (17.2-51.8) (55.5-74.4) \nBowel 16 5 49 28 98 36.4 90.7 76.2 63.6 66.3 \n(22.2-50.6) (83.0-98.5) (58.0-94.4) (52.9-74.4) (57.0-75.7) \nTP: true positive; FP: false positive; TN: true negative; FN: false negative; PPV: positive predictive value; NPV: negative predictive value \n\nEva Maria de Jesus Paiva et al. \nActa Obstet Ginecol Port 2025;19(4):268-279 275 \ndiagnosed 131 patients with a sensitivity of 90.3% \n(131/145) (95% CI 85.5-95.2) and specificity of 60.0% \n(9/15) (95% CI 35.2-84.8). MRI had lower sensitivity \nand higher specificity in the anterior compartment in \ncontrast to the posterior compartment. \nOvarian Endometriosis – Comparison of TVUS \nand MRI \nIn an effort to compare the performance of TVUS and \nMRI in diagnosing ovarian endometriosis, we analyzed \nthe 91 patients who had both exams performed pre- \noperatively . In this group, 51 (56.0%) patients had ova -\nrian endometriomas according to surgery . We found \nthat they performed similarly as sensitivity and speci -\nficity were 90.2% (46/51) (95% CI 82.0-98.4) and \n87.5 % (35/40) (95% CI 77.3-97.8) for TVUS and \n94.1% (48/51) (95% CI 87.7-100) and 77.5% (31/40) \nfor MRI (95% CI 64.6-90.4), respectively (Table V). \nDeep Endometriosis – Comparison of SVG and \nMRI \nIn the same way , for comparison of the diagnostic ac -\ncuracy of SVG and MRI in identifying DE lesions, we \nanalyzed the patients who undertook both these tests \nprior to surgery . Out of 49 patients, all except for 2 \n(4.1%) had DE upon surgical evaluation. Lesions were \nobserved in the posterior compartment of all the pa -\ntients and 12 (24.5%) of them had simultaneous fin -\ndings of DE in the anterior compartment. In Table V we \nsummarize the diagnostic performance of SVG and \nMRI in this group of patients. \nIn both exams, each patient without DE was classi -\nfied as having it on the posterior compartment and for \nthis reason, specificity for this location was 0.0%. Con -\nsidering overall DE, MRI and SVG performed similar -\nly . Only for the detection of lesions on the uterosacral \nligaments, MRI appeared to be slightly more sensitive \nwith 63.4% (26/41) (95% CI 48.7-78.2) compared to \n31.7% (13/41) (95% CI 17.5-46.0) when using SVG. \nDISCUSSION \nIn this study , we analyzed the diagnostic accuracy of \nTABLE III. DIAGNOSTIC PERFORMANCE OF TVUS, SVG AND TVUS+SVG FOR PREOPERATIVE DIAGNOSIS OF \nENDOMETRIOSIS. \nSite TVUS SVG p TVUS+SVG \nOvarian endometriosis Sens 95.7 (89.8-100) 78.3 (66.3-90.2) 0.002 95.7 (89.8-100) \nSpec 91.3 (83.2-99.5) 95.7 (89.8-100) 91.3 (83.2-99.5) \nDeep endometriosis Sens 3.6 (0.0.7.6) 83.1 (75.1-91.2) <0.001 83.1 (75.1-91.2) \nSpec 90.9 (73.9-100) 54.5 (25.1-84.0) 54.5 (25.1-84.0) \nAnterior compartment Sens 0.0 (0.0-0.0) 10.5 (0.0-24.3) 0.125 10.5 (0.0-24.3) \nSpec 98.6 (96.0-100) 95.9 (91.5-100) 95.9 (91.5-100) \nBladder Sens 0.0 (0.0-0.0) 7.1 (0.0-20.6) 0.250 7.1 (0.0-20.6) \nSpec 98.7 (96.3-100) 96.2 (92.0-100) 96.2 (92.0-100) \nUreters Sens 0.0 (0.0-0.0) 0.0 (0.0-0.0) 1.000 0.0 (0.0-0.0) \nSpec 98.8 (96.5-100) 97.6 (94.4-100) 97.6 (94.4-100) \nPosterior compartment Sens 3.7 (0.0-7.7) 82.9 (74.8-91.1) <0.001 82.9 (74.8-91.1) \nSpec 91.7 (76.0-100) 50.0 (21.7-78.3) 50.0 (21.7-78.3) \nUterosacral ligaments Sens 1.5 (0.0-4.4) 37.3 (25.7-48.9) <0.001 37.3 (25.7-48.9) \nSpec 100 (100-100) 76.0 (59.3-92.7) 76.0 (59.3-92.7) \nUterine torus, rectovaginal septum Sens 4.4 (0.0-9.3) 72.1 (61.4-82.7) <0.001 72.1 (61.4-82.7) \nand posterior vaginal wall Spec 96.0 (88.3-100) 40.0 (20.8-59.2) 40.0 (20.8-59.2) \nBowel Sens 2.4 (0.0-7.2) 34.1 (19.6-48.7) <0.001 34.1 (19.6-48.7) \nSpec 100 (100-100) 90.4 (82.4-98.4) 90.4 (82.4-98.4) \nData reported as % (95% CI). Sens: Sensitivity; Spec: Specificity \n\nEndometriosis diagnosis: a retrospective study on the use of transvaginal ultrasound, sonovaginography and magnetic resonance imaging \n276 Acta Obstet Ginecol Port 2025;19(4):268-279 \nTABLE IV. DIAGNOSTIC PERFORMANCE OF MAGNETIC RESONANCE IMAGING FOR PREOPERATIVE DIAGNOSIS OF ENDOMETRIOSIS. \nSensitivity Specificity PPV NPV Accuracy \nSite TP (n) FP (n) TN (n) FN (n) N (95% CI) (95% CI) (95% CI) (95% CI) (95% CI) \n(%) (%) (%) (%) (%) \nOvarian endometriosis 61 15 62 6 144 91.0 80.5 80.3 91.2 85.4 \n(84.2-97.9) (71.7-89.4) (71.3-89.2) (84.4-97.9) (79.7-91.2) \nDeep endometriosis 131 6 9 14 160 90.3 60.0 95.6 39.1 87.5 \n(85.5-95.2) (35.2-84.8) (92.2-99.1) (19.2-59.1) (82.4-92.6) \nAnterior compartment 20 5 101 12 138 62.5 95.3 80.0 89.4 87.7 \n(45.7-79.3) (91.3-99.3) (64.3-95.7) (83.7-95.1) (82.2-93.2) \nBladder 15 5 108 8 136 65.2 95.6 75.0 93.1 90.4 \n(45.8-84.7) (91.8-99.4) (56.0-94.0) (88.5-97.7) (85.5-95.4) \nUreters 3 3 118 8 132 27.3 97.5 50.0 93.7 91.7 \n(1.0-53.6) (94.8-100) (10.0-90.0) (89.4-97.9) (87.0-96.4) \nPosterior compartment 127 9 9 15 160 89.4 50.0 93.4 37.5 85.0 \n(84.4-94.5) (26.9-73.1) (89.2-97.6) (18.1-56.9) (79.5-90.5) \nUterosacral ligaments 68 11 31 28 138 70.8 73.8 86.1 52.5 71.7 \n(61.7-79.9) (60.5-87.1) (78.4-93.7) (39.8-65.3) (64.2-79.3) \nUterine torus, rectovaginal septum 101 21 19 15 156 87.1 47.5 82.8 55.9 76.9 \nand posterior vaginal wall (81.0-93.2) (32.0-63.0) (76.1-89.5) (39.2-72.6) (70.3-83.5) \nBowel 50 3 65 23 143 66.7 95.6 94.3 72.2 80.4 \n(56.0-77.3) (90.7-100) (88.1-100) (63.0- 81.5) (73.9-86.9) \nTP: true positive; FP: false positive; TN: true negative; FN: false negative; PPV: positive predictive value; NPV: negative predictive value \nTVUS, SVG and MRI, three wide -\nly used imaging exams for the \ndiagnosis of endometriosis. Their \ndiagnostic performance varies \nacross published literature as the -\nse are all dependent on operator or \ninterpreter experience. \nTVUS and pelvic MRI were \nhighly accurate for the diagnosis of \novarian endometriosis. Our results \nalign with those from a recent sys -\ntematic review which reported a \nsensitivity of 70.86-96% and spe -\ncificity of 71-96% for TVUS as well \nas a sensitivity of 76.9-94% and \nspecificity of 71-93.9% for MRI 19 .\nEven though our study was retros -\npective, our ultrasound results for \nendometrioma detection also \nmatch those from a recent multi -\ncenter prospective study , streng- \nthening our findings 20 . Regarding \nDE detection using TVUS, our re -\nsults for its diagnostic sensitivity \nare lower than reported in the \nmentioned studies which we attri -\nbute to their more robust prospec -\ntive methodology . Furthermore, as \nthis center regularly uses SVG for \nDE assessment, TVUS reports may \nbe less descriptive for these kinds \nof lesions. We attribute this lower- \nthan- expected result to these fac -\ntors, as well as to others such as the \nlengthy data collection period. \nOver the past decade, substantial \nresearch and innovation have dri -\nven major advances in imaging \ntechnology and more standardised \nreporting practices. In the future, it \nwould be interesting to investiga -\nte the extent to which these deve -\nlopments, such as IDEA group \nconsensus adoption, since its pu -\nblication may have impacted diag -\nnostic acuity of TVUS over time in \n\nEva Maria de Jesus Paiva et al. \nActa Obstet Ginecol Port 2025;19(4):268-279 277 \nour centre. As with any operator-dependent imaging \nexam we are also always conditioned by possible tech -\nnical errors, which can introduce variability . Nonethe -\nless, the specificity of TVUS for DE detection was high, \nsuggesting that a positive result is highly indicative of \nDE but a negative finding does not exclude it, in line \nwith the most recent ESHRE guidelines for diagnostic \nimaging 4.\nSVG showed good diagnostic accuracy for overall \nDE although, when considering specific sites, it was lo -\nwer than what is described in the literature 15 . Barra et \nal obtained a sensitivity of 89.4% and specificity of \n79.4% for posterior DE using gel SVG while our sensi -\ntivity was 83.9% and specificity of 50.0% for the same \nlocation 21 . Our lack of specificity seems to be mainly \ndriven by higher false positive rates for endometriosis \nin the uterine torus, rectovaginal septum and posterior \nvaginal wall. Even though we have a good detection \nrate for overall lesions, this lack of specificity means \nthat there is still an opportunity to improve with this \ndiagnostic tool. Based on our comparison of the diag -\nnostic accuracy of TVUS and SVG, we do believe we \ncan conclude that, by performing these exams simul -\ntaneously as a routine, our rates of detection of ovarian \nendometriosis (sensitivity 95.7% (95%CI 89.8-100) \nand specificity 91.3% (95%CI 83.2-99.5)) and DE \n(sensitivity 83.1% (95%CI 75.1-91.2) and specificity \n54.5% (95%CI 25.1-84.0)) are reassuring for our pa -\ntients. \nFor overall DE diagnosis by MRI, we obtained a sen -\nsitivity of 90.3% (95%CI 85.5-95.2) and specificity of \n60.0% (95%CI 35.2-84.8) which is quite comparable \nto what Nisenblat et al reported of overall sensitivity of \n94% (95%CI 90-97) and specificity of 77% (95%CI \n44-100%) 17 . Similarly to SVG, our specificity was wor -\nse particularly due to higher false positive rates for the \nuterine torus, rectovaginal septum and posterior vagi -\nnal wall. When focusing on specific locations, we ob -\ntained slightly worse results than those described in \nthe literature 8,17,22 . This suggests that while MRI shows \nTABLE V. DIAGNOSTIC PERFORMANCE OF TVUS AND MRI FOR PREOPERATIVE DIAGNOSIS OF OVARIAN \nENDOMETRIOSIS AND DIAGNOSTIC PERFORMANCE OF SVG AND MRI FOR PREOPERATIVE DIAGNOSIS OF \nDEEP ENDOMETRIOSIS. \nSite TVUS MRI p\nOvarian endometriosis (N=91) Sens 90.2 (82.0-98.4) 94.1 (87.7-100) 0.146 Spec 87.5 (77.3-97.8) 77.5 (64.6-90.4) \nSVG RM \nDeep endometriosis (N=49) Sens 89.4 (80.6-98.2) 85.1 (74.9-95.3) 0.774 Spec 0 (0.0-0.0) 0.0 (0.0-0.0) \nAnterior compartment Sens 16.7 (0.0-37.8) 50.0 (21.7-78.3) 0.453 Spec 94.6 (87.3-100) 97.3 (92.1-100) \nBladder Sens 10.0 (0.0-28.6) 50.0 (19.0-81.0) 0.219 Spec 94.9 (88.0-100) 94.9 (88.0-100) \nUreters Sens 0 (0.0-0.0) 0.0 (0.0-0.0) 0.500 Spec 95.5 (89.3-100) 100 (100-100) \nPosterior compartment Sens 89.4 (80.6-98.2) 85.1 (74.9-95.3) 0.774 Spec 0 (0.0-0.0) 0.0 (0.0-0.0) \nUterosacral ligaments Sens 31.7 (17.5-46.0) 63.4 (48.7-78.2) 0.043 Spec 57.1 (20.5-93.8) 85.7 (59.8-100) \nUterine torus, rectovaginal septum Sens 73.7 (59.7-87.7) 78.9 (66.0-91.9) 1.000 and posterior vaginal wall Spec 10.0 (0.0-28.6) 20.0 (0.0-44.8) \nBowel Sens 50.0 (30.8-69.2) 69.2 (51.5-87.0) 1.000 Spec 82.6 (67.1-98.1) 100 (100-100) \nData reported as % (95% CI). Sens: Sensitivity; Spec: Specificity \n\nEndometriosis diagnosis: a retrospective study on the use of transvaginal ultrasound, sonovaginography and magnetic resonance imaging \n278 Acta Obstet Ginecol Port 2025;19(4):268-279 \nan adequate overall accuracy for diagnosing DE, there \nis room for optimizing its performance at specific site \ndetection of lesions to help achieve a more precise \nmapping of the disease. \nRegarding the anterior compartment, the lower pre -\nvalence of disease limits the interpretation of our re -\nsults. Reassuringly , the high specificity found in both \nSVG and MRI, allows us to be confident when disease \nis diagnosed in these exams. \nIn the direct comparison between SVG and MRI, re -\nsults were quite similar. However, for disease in the ute -\nrosacral ligaments, MRI seems to have a higher sensi -\nbility with similar specificity to SVG. This means that, \nin cases with high clinical suspicion of disease in this \nlocation, MRI seems to have an important role. \nUltrasound has several advantages to MRI, such as \nbeing a dynamic, innocuous and cost-effective exam. \nAs such, its role as a first-line modality for screening \nand diagnosis of endometriosis is well established 10 .\nTVUS serves a purpose beyond being a diagnostic test, \nas it can help to understand the extent and site of lesions \nby taking into consideration real-time tenderness and \nmobility of the structures, giving an idea about the exis -\ntence of adhesions and obliteration of the pelvic pou -\nches 7. However, it relies extensively on the operator’s \nexperience and its images cannot be adequately revie -\nwed after the examination by other clinicians. Further -\nmore, TVUS may be refused or impossible to perform \nin some patients. On the other hand, MRI provides ac -\ncurate identification of endometriotic lesions, particu -\nlarly in the posterior compartment and some major be -\nnefits of its use are the simultaneous multiple plane as -\nsessment and its capability to allow the retrospective re -\nview of images, which is most useful for preoperative \nworkup 9. Moreover, it allows the examination of organs \nand regions not accessible to the ultrasound probe. \nWe identify several limitations in this study . Firstly , \nwe have limitations inherent to the retrospective de -\nsign of the study and the use of medical records, thus \nour results rely on the quality and quantity of infor -\nmation recorded. Additionally , the time interval bet -\nween performing the different tests was not considered. \nThis could result in the disease progressing while pa -\ntients were undergoing various imaging exams or awai -\nting surgery , leading to an underestimation of the re -\nsults. Despite the fact that visual inspection of lesions \nduring surgery is not fully specific, we also did not con -\nsider histopathology as an additional reference stan -\ndard, as our reports did not have sufficient quality , even \nthough the specimens were adequately marked during \nsurgery . The use of the same operators for both TVUS \nand SVG reduces inter-operator variability but may in -\ntroduce incorporation bias when both exams are per -\nformed by the same clinician. By contrast, the limited \nnumber of scans performed by other clinicians could \nalso contribute to discrepancies in findings. Besides, \neven though the majority of the TVUS and SVG were \nperformed by the same 2 ultrasonographers, not all \nMRIs were performed by the same radiologists; howe -\nver, from 2020, even the exams performed outside of \nthe hospital could be reviewed by a multidisciplinary \nteam, minimizing this limitation. Furthermore, clini -\ncians were not blinded to the patient’s clinical history , \nwhich can introduce heterogeneity in our data although \nit better reflects day-to-day practice. Lastly , this study \nmay be subject to patient selection bias as it only in -\ncludes women who underwent surgery for endome -\ntriosis diagnosis and treatment. \nFinally , some key strengths of our study are its large \nsample of patients from 14 years of clinical care in a \ncenter with an experienced team in dealing with diag -\nnosing and treating this disease. The imaging exams \nperformed in this hospital are standardly described to \nensure a complete and comprehensive evaluation and \nsurgeries were performed mainly by the same team. \nIn conclusion, our results suggest that TVUS is \nhighly accurate for the diagnosis of ovarian endome -\ntriosis and remains the cornerstone imaging modality \nfor this condition. 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Diagnostic accuracy of transvaginal ultrasound for de -\ntection of endometriosis using International Deep Endometriosis \nAnalysis (IDEA) approach: prospective international pilot study . Ul -\ntrasound Obstet Gynecol. 2022;60(3):404-13. \n21. Barra F , Leone Roberti Maggiore U, Evangelisti G, Scala C, \nAlessandri F , Vellone VG, et al. A prospective study comparing rec -\ntal water contrast-transvaginal ultrasonography with sonovagino -\ngraphy for the diagnosis of deep posterior endometriosis. Acta Obs -\ntet Gynecol Scand. 2021;100(9):1700-11. \n22. Indrielle-Kelly T, Frühauf F , Fanta M, Burgetova A, Lavu D, \nDundr P , et al. Diagnostic Accuracy of Ultrasound and MRI in the \nMapping of Deep Pelvic Endometriosis Using the International \nDeep Endometriosis Analysis (IDEA) Consensus. Biomed Res Int. \n2020;2020:3583989. \nAUTHOR CONTRIBUTIONS \nEva Paiva: Conceptualization, Investigation, Methodology , Project ad -\nministration, Visualisation, Writing – original draft. Ana Mafalda da \nCosta Castro Neves: Resources, Validation, Writing – review & edi -\nting. Pedro Viana Pinto: Conceptualization, Investigation, Methodo -\nlogy , Project administration, Visualization, Writing – original draft. Ana \nMargarida Póvoa: Resources, Validation, Writing – review & editing. \nAndreia Teixeira: Resources, Validation, Writing – review & editing. \nCONFLICT OF INTEREST \nThe authors declare that they have no conflict of interest. \nCORRESPONDENCE TO: \nEva Maria de Jesus Paiva \nE-mail: evamjpaiva@gmail.com \nhttps://orcid.org/0009-0000-0960-6218 \nRECEIVED: 22/01/2025 \nACCEPTED: 02/12/2025","source_license":"CC0","license_restricted":false}