{"paper_id":"62dae1d3-5107-47cd-b3df-69469722d58d","body_text":"WOMEN’S IMAGING\nIran J Radiol. 2022 October; 19(4):e127068.\nPublished online 2023 January 20.\nhttps://doi.org/10.5812/iranjradiol-127068.\nResearch Article\nDiagnostic Accuracy of Transvaginal Sonography for Deeply\nInfiltrating Endometriosis and Pouch of Douglas Obliteration in the\nPresence or Absence of Ovarian Endometrioma\nNahid Sadighi\n 1, 2, Behnaz Moradi\n 1, 2, Masoumeh Gity\n 1, 2, Behnaz Boroujerdirad 3, Fateme\nDavari-tanha 4, Reza Daneshvar 5 and Javid Azadbakht\n 6, 7, *\n1Advanced Diagnostic and Interventional Radiology Research Center (ADIR), Medical Imaging Center, Imam Khomeini Hospital Complex, Tehran University of Medical\nSciences, Tehran, Iran\n2Department of Radiology , Yas Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran\n3Department of Radiology , Sina Hospital, Tehran University of Medical Sciences, Tehran, Iran\n4Department of Obstetrics and Gynecology , Yas Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran\n5Department of Radiology , Tehran University of Medical Sciences, Tehran, Iran\n6Department of Radiology , Shahid Beheshti Hospital, Kashan University of Medical Sciences, Kashan, Iran\n7Department of Radiology , Faculty of Medicine, Kashan University of Medical Sciences, Kashan, Iran\n*Corresponding author: Department of Radiology , Shahid Beheshti Hospital, Kashan University of Medical Sciences, Qotb Ravandi Blvd., P. O. Box: 8715981151, Kashan, Iran. Tel:\n+98-3155005712, Email: javidazadbakht2@gmail.com\nReceived 2022 April 24; Revised 2022 November 19; Accepted 2022 November 27.\nAbstract\nBackground: Endometriosis is one of the most common gynecological diseases worldwide. Significant attention has been drawn\nto this multiorgan and often painful disorder.\nObjectives: This study aimed to examine the accuracy of transvaginal sonography (TVS) in the diagnosis of deeply infiltrating en-\ndometriosis (DIE) with respect to the presence or absence of ovarian endometrioma (OE).\nPatients and Methods: This cross-sectional study was performed on all patients undergoing TVS before gynecological laparoscopy .\nWith pathological confirmation as the standard reference, the diagnostic accuracy of TVS for DIE and pouch of Douglas (POD) oblit-\neration was compared with that of laparoscopy in the anterior and posterior pelvic compartments with respect to the presence or\nabsence of OE. Agreement between TVS and laparoscopy was evaluated for each case, and Cohen’s kappa statistic was measured for\neach site of involvement. Moreover, sensitivity , specificity , negative and positive predictive values, and likelihood ratios of TVS were\ncalculated, with laparoscopy as the reference test.\nResults: A total of 110 patients, with a mean age of 37.20 ± 7.16 years, were recruited in this study . The accuracy , sensitivity , and\nnegative predictive value of TVS for the diagnosis of DIE and POD obliteration were estimated at 89.5%, 58.3%, and 88.9% in the anterior\npelvic compartment and 93.3%, 92%, and 70.6% in the posterior pelvic compartment, respectively . Nevertheless, TVS showed lower\nsensitivity for detecting pelvic adhesions and peritoneal cysts compared to laparoscopy . The presence of OE did not significantly\nincrease the accuracy of TVS for the diagnosis of DIE or POD obliteration (P > 0.05).\nConclusion: The present study showed that TVS is an adequately accurate and non-invasive diagnostic tool for the detection and\nmapping of DIE and POD obliteration, regardless of the presence of OE. TVS may waive the need for exploratory laparoscopy in DIE\nor at least facilitate precise pre-procedural DIE mapping.\nKeywords: Endometriosis, Endometrioma, TVS, Laparoscopy, Pouch of Douglas\n1. Background\nEndometriosis, as a multiorgan and often painful dis-\norder, is recognized as one of the most common gyneco-\nlogical diseases, associated with various morbidities. It is\ndefined as the abnormal growth of endometrium-type tis-\nsue outside the endometrial cavity (1). The most common\nsites for endometriosis include the ovaries, peritoneum,\nand uterosacral ligament, while it less frequently involves\nthe bladder, vagina, and gastrointestinal tract (1, 2). Deeply\ninfiltrating endometriosis (DIE) is a specific type of en-\ndometriosis, penetrating more than 5 mm below the peri-\ntoneal surface. Laparoscopy and subsequent histological\nconfirmation are the mainstay for a definitive diagnosis.\nHowever, there are many challenges in the application of\nimaging modalities. Among available imaging modalities,\nmagnetic resonance imaging (MRI) has been postulated as\nCopyright © 2023, Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License\n(http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly\ncited.\n\nSadighi N et al.\nthe most accurate method for DIE mapping (3).\nSo far, various imaging modalities have been recom-\nmended in the literature to diagnose and localize DIE, in-\ncluding transvaginal sonography (TVS), transrectal sonog-\nraphy (TRS) or rectal endoscopic sonography (RES), and\nMRI (4, 5). Deeply infiltrating endometriosis in the\nuterosacral ligament, visceral wall, or pouch of Douglas\n(POD) (responsible for POD obliteration) is associated with\nserosal adhesion, fibrosis, and rectal DIE and can be identi-\nfied via TVS (6, 7). Moreover, POD obliteration is associated\nwith DIE in the posterior pelvic compartment (PPC).\nTransvaginal sonography is recommended as the first-\nline imaging modality to diagnose ovarian and bladder\nendometriosis (1). On the other hand, ultrasound is well\nknown for its high value in the diagnosis of ovarian en-\ndometrioma (OE), and observation of OE in TVS may raise\nthe suspicion of endometriosis (8, 9). Additionally , iden-\ntification of ovarian fixation on TVS through visualization\nof a not freely mobile ovary (under gentle probe pressure)\nis strongly associated with the detection of endometriosis\nvia laparoscopy (10). These findings all emphasize that pre-\noperative TVS, as a practical high-yield diagnostic tool for\npatients with suspicion of DIE/POD obliteration, may waive\nthe need for laparoscopy or exploratory laparotomy in un-\nnecessary cases.\n2. Objectives\nThis study aimed to determine the accuracy of TVS in\nthe diagnosis of DIE and POD obliteration with regard to\nthe presence or absence of OE.\n3. Patients and Methods\nThe current study was approved by the local insti-\ntutional ethics committee. In this analytical study on\nprospectively collected data, 110 clinically suspected cases\nof DIE or POD obliteration, who were referred to our ter-\ntiary care teaching health center during 2020 - 2021 and\nwere scheduled for a laparoscopic evaluation, were in-\ncluded. All patients underwent TVS before laparoscopy . Af-\nter systematically examining the uterus, ovaries, fallopian\ntube, and other relevant pelvic structures via TVS and la-\nparoscopy , the accuracy of these two modalities in diag-\nnosis of DIE and POD obliteration was assessed and com-\npared, with pathological confirmation as the gold stan-\ndard. Our findings were further stratified based on the\npresence, size, laterality , and location of OE, as well as the\npresence of hydro- or hematosalpinx, peritoneal cysts, and\npelvic adhesions.\n3.1. Study Population\nThis cross-sectional study was conducted in a tertiary\nteaching center with highly skilled staff for the manage-\nment of endometriosis. Consecutive patients with clini-\ncally suspected pelvic endometriosis, who were scheduled\nfor laparoscopy , were asked to join the study after explain-\ning the study plan and obtaining written informed con-\nsent. Information leaflets explaining the study objectives\nand methods were given to all eligible participants. Pa-\ntients unable to undergo a TVS exam (e.g., in case of vir-\nginity or TVS avoidance due to procedural anxiety) were ex-\ncluded from the study .\n3.2. Procedures\nAttending clinicians took the clinical history of all pa-\ntients. Transvaginal sonography exams were performed\nby two radiologists who were highly experienced in gyne-\ncological ultrasonography (with seven and 25 years of gy-\nnecological ultrasonography experience, respectively) and\nblinded to the patients’ history . Discrepancies in the re-\nsults were resolved by consensus. All laparoscopic surg-\neries were performed by a laparoscopic surgeon (with 20\nyears of experience), who was highly skilled in reproduc-\ntive surgeries and management of advanced endometrio-\nsis.\n3.2.1. Transvaginal Sonography\nAll participants underwent TVS examination in the\ndorsal lithotomy position, using a high-frequency/high-\nresolution transvaginal volume probe with a systematic\napproach, involving: (1) visualization of the uterus in the\ncoronal and sagittal planes; (2) searching the ovaries for\nOE and assessing the ovarian fixation; (3) visualization of\nfallopian tubes for hydrosalpinx, hematosalpinx, and ad-\nhesion; and (4) inspection of the rest of the pelvis for peri-\ntoneal cysts and signs of adhesion. Ovarian endometrioma\nwas reported for any thick-walled ovarian cyst with a ho-\nmogeneous low-level internal echo and measured by divid-\ning the sum of diameters (inner to inner) in three orthog-\nonal planes by three (11).\nTo evaluate pelvic adhesions, the ovarian and uterine\nmobility was assessed using a bimanual examination (by\napplying gentle pressure on the ovary or cervix with a\nvaginal probe and alternating abdominal pressure on the\novary or uterine fundus by the sonographer’s free hand),\nfollowed by visualization of free or limited motility of the\novary and uterus across adjacent structures. Hypoechoic\nor isoechoic solid nodules/masses with irregular margins\nthat were tender on palpation and fixed to the surround-\ning pelvic structures were labeled as DIE (Figure 1) (12, 13).\n2 Iran J Radiol. 2022; 19(4):e127068.\n\nSadighi N et al.\nAlso, focal or diffuse hypoechoic thickening of the rectosig-\nmoid colon muscularis propria (thickness > 3 mm), some-\ntimes protruding into the bowels, was considered as rec-\ntosigmoid DIE (14). The presence of lesions was recorded\nin a database file location-wise, using a spreadsheet in Mi-\ncrosoft Excel for Windows.\n3.2.2. Laparoscopy\nPre-procedural and procedural planning was per-\nformed for any individual case according to in-depth\ninsights into the pelvic anatomy by TVS examinations.\nPatients were asked not to eat or drink for eight hours\nbefore laparoscopy . The procedure was performed under\ngeneral anesthesia in the steep Trendelenburg position.\nThe abdominopelvic cavity was inflated with carbon\ndioxide using a cannula (placed through a subumbilical\nincision), increasing the intraperitoneal pressure up to\n13 - 14 mmHg. Laparoscopy was performed according to a\nsystematic approach not to miss small endometriotic de-\nposits. Approaching from the left side, the left ureter was\ndissected and inspected for any signs of endometriosis.\nThe central pelvis was evaluated for the presence of rec-\ntosigmoid endometriosis, pelvic adhesions, or peritoneal\ncysts.\nFinally , the right ureter was dissected to search for en-\ndometriotic lesions. Endometriotic deposits or nodules,\nif found, were removed in any stage through a sharp in-\ncision using laparoscopic scissors. If present, pelvic ad-\nhesions were excised, and peritoneal/ovarian cystectomy\nor myomectomy was followed by intraabdominal sutur-\ning. In case of a posterior pelvic adhesion, both ovaries\nwere suspended from the ipsilateral round ligaments to\ndecrease the risk of subsequent adhesiogenesis.\n3.3. Statistical Analysis\nStatistical analysis was performed using SPSS version\n22.0 (IBM Corp. Released 2013. IBM SPSS Statistics for Win-\ndows, Version 22.0. Armonk, NY: IBM Corp). The accu-\nracy of TVS for each site of involvement was examined by\nmeasuring sensitivity , specificity , positive predictive value\n(PPV), negative predictive value (NPV), positive likelihood\nratio (LR+) and negative likelihood ratio (LR-). Moreover,\nFisher’s exact test was used to evaluate the relationship be-\ntween TVS and laparoscopic findings of DIE, both in the\nanterior pelvic compartment (APC) and PPC. The level of\nagreement was calculated based on kappa coefficients (κ),\nwith κ values of 0.81 - 1.0, 0.61 - 0.80, 0.41 - 0.60, 0.21 - 0.40,\nand < 0.20 representing very good, good, moderate, fair,\nand poor agreement, respectively . In all tests, a P-value less\nthan 0.05 was considered statistically significant.\n4. Results\nThis study was conducted on 110 patients, with a mean\nage of 37.20 ± 7.16 years (mean ± SD), ranging from 18 to\n52 years. Right-sided OE was detected in 73 (66.4%) patients\non both TVS and laparoscopy , with an average size of 48.6\n± 20.9 mm (range, 6 - 120 mm). Left-sided OE was recorded\nin 74 (67.3%) patients on both TVS and laparoscopy , with an\naverage size of 21.2 ± 48.7 mm (range, 10 - 130 mm). Other\ndescriptive findings are presented in Table 1.\nAccording to Table 2, TVS and laparoscopy were sig-\nnificantly correlated with the observation of DIE and POD\nobliteration in the APC, regardless of the presence, lateral-\nity , or size of OE (P < 0.0001 for the presence or absence of\nOE; P < 0.0001 for uni- or bilateral OE; and P < 0.0001 for\nOE size ≤ 48 or > 48 mm). A similar finding was reported\nfor DIE and POD obliteration in PPC (P < 0.0001 for OE pres-\nence and P = 0.006 for OE absence; P < 0.0001 for uni- or\nbilateral OE; and P = 0.002 for OE ≤48 mm and P < 0.0001\nfor OE > 48 mm).\nTransvaginal sonography was the least sensitive\nmodality (53.8%) to identify DIE in APC when there was\naccompanying OE, measuring ≤ 48 mm in size. On the\nother hand, it was the most sensitive modality (100%) for\nidentifying DIE in PPC when OE was absent; it was also\nhighly specific for the detection of DIE (97.4 - 100%). The\nPPV and NPV of TVS for DIE diagnosis were estimated at\n87.5 - 100% and 58.3 - 100%, respectively , depending on the\npelvic compartment and location involved. Based on the\nresults, TVS was 100% accurate in diagnosing DIE and POD\nobliteration in PPC when there was no OE, while it was\nonly 82% accurate for demarcating DIE in APC when there\nwere bilateral OEs (Table 3).\nThe agreement of TVS and laparoscopic findings for the\ndiagnosis of DIE or POD obliteration roughly fell within the\nmoderate agreement range of kappa coefficients. Agree-\nment was very good in the evaluation of DIE and POD oblit-\neration in APC if the patient had unilateral OE; a similar\nfinding was reported in the evaluation of DIE and POD\nobliteration in PPC if the patient showed no OE on TVS.\nThe accuracy , sensitivity , and NPV of TVS for the detec-\ntion of endometriosis in APC were estimated at 89.5%, 58.3%,\nand 88.9%, respectively , and the corresponding values for\nPPC were 93.3%, 92%, and 70.6% respectively .\n5. Discussion\nDeeply infiltrating endometriosis predominantly in-\nvolves women of reproductive age. Early detection of DIE\nvia imaging facilitates a timely treatment to alleviate the\npatient’s symptoms and increase their quality of life and\nIran J Radiol. 2022; 19(4):e127068. 3\n\nSadighi N et al.\nTable 1. Comparison of the Presence, Number, and Location of Ovarian Endometrioma and Other Associated Findings on Sonography and Laparoscopy a\nVariables Ultrasound (n = 110) Laparoscopy (n = 110) P-value\nLaterality\nRight ovary 0.662 b\nNormal 37 (33.6) 35 (31.8)\nOE 73 (66.4) 75 (68.2)\nLeft ovary\nNormal 36 (32.7) 32 (29.1)\nOE 74 (67.3) 78 (70.9)\nNumber\nNumber of OEs in the right ovary 0.127\n1 51 (69.9) 43 (57.3)\n> 1 22 (30.1) 32 (42.7)\nNumber of OEs in the left ovary 0.283\n1 56 (75.7) 52 (66.7)\n> 1 18 (24.3) 26 (33.3)\nCompartment involved\nAPC 0.153\nNegative 96 (85.7) 88 (78.6)\nB. dome 3 (2.7) 4 (3.6)\nB. base 12 (10.7) 17 (15.2)\nB. trigone 1 (0.9) 3 (2.7)\nPPC 0.315\nNegative 36 (22.6) 26 (16.4)\nRVS 1 (0.6) 1 (0.6)\nDU 4 (2.5) 13 (8.2)\nUSL 70 (44) 66 (41.5)\nPVF 1 (0.6) 1 (0.6)\nVW 1 (0.6) 0 (0)\nLR 7 (4.4) 3 (1.9)\nUR 28 (17.6) 30 (18.9)\nRS 11 (6.9) 19 (11.9)\nOther findings\nHydrosalpinx 0.423\nNegative 98 (89.1) 94 (85.5)\nPositive 12 (10.9) 16 (14.5)\nHematosalpinx 0.446\nNegative 108 (98.2) 105 (95.5)\nPositive 2 (1.8) 5 (4.5)\nEvidence of pelvic adhesion 0.027\nNegative 34 (30.9) 19 (17.3)\nPositive 76 (69.1) 91 (82.7)\nPeritoneal cyst < 0.0001\nNegative 80 (72.7) 107 (97.3)\nPositive 30 (27.3) 3 (2.7)\nAbbreviations: APC, anterior pelvic compartment; B. base, bladder base; B. dome, bladder dome; B. trigone, bladder trigone; DIE, deeply infiltrating endometriosis; DU,\ndistal ureter; LR, lower rectum; OE, ovarian endometrioma; PPC, posterior pelvic compartment; PVF, posterior vaginal fornix; RS, rectosigmoid; RVS, rectovaginal septum;\nUR, upper rectum; USL, uterosacral ligament; VW, vaginal wall.\na Values are expressed as No. (%).\nb This figure represents the significance of laterality according to either TVS or laparoscopy .\n4 Iran J Radiol. 2022; 19(4):e127068.\n\nSadighi N et al.\nTable 2. Agreement Between Transvaginal Sonography and Laparoscopic Findings for the Detection of Deeply Infiltrating Endometriosis, Stratified by the Involved Compart-\nment and Location and the Presence, Laterality , and Size of Ovarian Endometrioma\nLaparoscopy\nP-value a Kappa coefficient\nNegative B. dome B. base B. trigone\nDIE in APC and POD obliteration with/without/with and without OE\nTVS < 0.0001/n b /< 0.0001 0.708/n b /0.711\nNegative 80/7/87 1/0/1 6/0/6 2/0/2\nB. dome 0/0/0 3/0/3 0/0/0 0/0/0\nB. base 1/0/1 0/0/0 11/0/11 0/0/0\nB. trigone 0/0/0 0/0/0 0/0/0 1/0/1\nDIE in PPC and POD obliteration with/without/with and without OE\nNegative RVS DU USL PVF LR UR RS\nTVS < 0.0001/0.006/< 0.0001 0.616/0.859/0.632\nNegative 24/2/26 0/n/0 0/0/0 3/0/3 0/n/0 0/n/0 5/0/5 2/n/2\nRVS 0/n/0 0/n/0 0/n/0 0/n/0 0/n/0 0/n/0 0/n/0 1/n/1\nDU 0/0/0 0/n/0 3/1/4 0/0/0 0/n/0 0/n/0 0/0/0 0/n/0\nUSL 0/0/0 1/n/1 6/0/6 54/3/57 0/n/0 0/n/0 2/1/3 3/n/3\nPVF 0/n/0 0/n/0 0/n/0 0/n/0 0/n/0 0/n/0 0/n/0 1/n/1\nVW 0/n/0 0/n/0 0/n/0 1/n/1 0/n/0 0/n/0 0/n/0 0/n/0\nLR 0/n/0 0/n/0 0/n/0 0/n/0 0/n/0 2/n/2 4/n/4 0/n/0\nUR 0/0/0 0/n/0 2/0/2 4/1/5 0/n/0 0/n/0 15/3/8 4/n/4\nRS 0/n/0 0/n/0 1/n/1 1/n/1 1/n/1 0/n/0 0/n/0 8/n/8\nDIE in APC and POD obliteration in unilateral/bilateral OE\nNegative B. dome B. base B. trigone\nTVS < 0.0001/< 0.0001 0.861/0.592\nNegative 46/34 1/0 0/6 0/2\nB. dome 0/0 2/1 0/0 0/0\nB. base 1/0 0/0 4/7 0/0\nB. trigone 0/n 0/n 0/n 1/n\nDIE in PPC and POD obliteration in unilateral/bilateral OE\nNegative RVS DU USL PVF LR UR RS\nTVS < 0.0001/< 0.0001 0.652/0.577\nNegative 17/7 n/0 0 / 0 1 /2 n/0 0 / 0 2 / 3 2 / 0\nRVS 0/n n/n 0/n 0/n n/n 0/n 0/n 1/n\nDU n/0 n/0 n/3 n/0 n/0 n/0 n/0 n/0\nUSL 0/0 n/1 2/4 22/32 n/0 0/0 1/1 2/1\nVW 0/n n/n 0/n 1/n n/n 0/n 0/n 0/n\nPVF n/0 n/0 n/0 n/0 n/0 n/0 n/0 n/1\nLR 0/0 n/0 0/0 0/0 n/0 1/2 2/2 0/0\nUR 0/0 n/0 1/1 1/3 n/0 0/0 6 / 9 0 / 4\nRS n/0 n/0 n/1 n/0 n/1 n/0 n/0 n/4\nDIE in APC and POD obliteration in ≥ 48 mm/< 48 mm OE\nNegative B. dome B. base B. trigone\nTVS < 0.0001/< 0.0001 0.727/0.683\nNegative 43/37 1/0 2/4 2/0\nB. dome 0/n 3/n 0/n 0/n\nB. base 0/1 0/0 5/6 0/0\nB. trigone n/0 n/0 n/0 n/1\nDIE in PPC and POD obliteration in ≥ 48 mm/< 48 mm OE\nNegative RVS DU USL PVF LR UR RS\nTVS 0.002/< 0.0001 0.577/0.662\nNegative 11/13 n/0 0/ 0 2/ 1 n/0 0/ 0 3/ 2 0/ 2\nRVS 0/0 n/0 0/3 0/0 n/0 0/0 0/0 1/0\nDU n/0 n/1 n/3 n/25 n/0 n/0 n/2 n/1\nUSL 0/0 n/0 3/0 29/0 n/0 0/1 0/2 2/0\nVW 0/n n/n 0/n 1/n n/n 0/n 0/n 0/n\nPVF 0/n n/n 0/n 0/n n/n 0/n 0/n 1/n\nLR 0/n n/n 0/n 0/n n/n 2/n 2/n 0/n\nUR 0/0 n/0 2/0 2/2 n/0 0/0 8/7 4/0\nRS 0/0 n/0 1/0 1/0 n/1 0/0 0/0 5/3\nAbbreviations: APC, anterior pelvic compartment; B. base, bladder base; B. dome, bladder dome; B. trigone, bladder trigone; DIE, deeply infiltrating endometriosis; DU, distal ureter; LR, lower rectum; n, not applicable; OE, ovarian\nendometrioma; POD, pouch of Douglas; PPC, posterior pelvic compartment; PVF, posterior vaginal fornix; RS, rectosigmoid; RVS, rectovaginal septum; TVS, transvaginal sonography; UR, upper rectum; USL, uterosacral ligament; VW,\nvaginal wall.\na All P-values are calculated using Fisher’s exact test.\nb All cases in this specific subgroup are TVS-negative/laparoscopy-negative; therefore, the level of agreement and significance are not applicable. All bilateral anatomic locations are treated separately .\nIran J Radiol. 2022; 19(4):e127068. 5\n\nSadighi N et al.\nFigure 1. A, Transvaginal sonography (TVS) presents a sizable right-sided ovarian endometrioma (OE) with a thick echogenic wall and low-level internal echogenicity (arrows)\nalong with an adjacent ipsilateral uterosacral ligament deeply infiltrating endometriosis (DIE) plaque (arrowhead). The DIE plaque has an angulated and irregular margin. B\nand C, TVS demonstrates an endometrioma (arrows) with adjacent irregular, amorphous, elongated, and hypoechoic foci of DIE deposition between clipper\nchance of conception (15). The prevalence of DIE and associ-\nated conditions, which impose a great burden on patients\nand healthcare systems, has prompted extensive research\nin this area. Generally , a definite diagnosis requires histo-\nlogical confirmation and laparoscopy . Nonetheless, imag-\ning plays a crucial role in establishing an initial diagnosis\nin a relevant clinical context and greatly assists in preop-\nerative mapping. In this regard, TVS, as a well-accepted,\nrapid, cost-effective, widely available, and non-invasive di-\nagnostic method, has been shown to be advantageous (1).\nPrevious studies have reported a higher frequency of\nleft-sided endometriomas (16, 17), while some research,\nsimilar to the present study , did not confirm this find-\ning (18). Single endometrioma (on either side) was 2 - 3\ntimes more common than multiple OEs. TVS was found\nto detect more single OEs than laparoscopy , while the lat-\nter found more multiple OEs than the former. According\nto the present findings, the most common extraovarian\nsites for DIE, found on both TVS and laparoscopy , were the\nuterosacral ligament (USL) in PPC and the bladder base in\nAPC; these findings are comparable to those of previous\nstudies (19).\nThe current results revealed that the sensitivity , PPV , ac-\ncuracy , and to a lesser extent, specificity of TVS for the de-\ntection of DIE was higher in PPC than APC; on the contrary ,\nNPV was higher for APC lesions. In this regard, Holland et\nal. reported that the sensitivity of TVS for the diagnosis of\nendometriosis in PPC was as low as 10 - 50% (18). Conversely ,\nbased on the current results, TVS was quite sensitive for de-\ntecting DIE in PPC (91.1 - 100%). According to our findings,\nDIE and POD obliteration were accurately identifiable via\nTVS, regardless of the presence, size, or laterality of pelvic\nendometriosis. On the contrary , Leonardi et al. found a\nhigher TVS detection rate for DIE when OE was present (17).\nThey declared that in cases without OE, the detection rate\nof TVS was lower to an extent which is not negligible (17).\nIn line with previous investigations (20), in the present\nstudy , the presence of OE on TVS could indicate more severe\n6 Iran J Radiol. 2022; 19(4):e127068.\n\nSadighi N et al.\nTable 3. Sensitivity , Specificity , Positive Predictive Value, Negative Predictive Value, and Accuracy of Transvaginal Sonography for the Diagnosis of Deeply Infiltrating En-\ndometriosis and Pouch of Douglas Obliteration Compared to Laparoscopy\nOE status and DIE location Sensitivity (%) Specificity (%) PPV (%) NPV (%) Accuracy (%) Kappa coefficient\nPresence\nPresence\nAPC 58.3 98.7 93.3 88.9 89.5 0.658\nPPC 92 100 100 70.6 93.3 0.787\nAbsence\nAPC - - - - - -\nPPC 100 100 100 100 100 100\nPresence and absence\nAPC 58.3 98.9 93.3 89.7 90.2 0.662\nPPC 92.5 100 100 72.2 93.7 0.801\nLaterality\nUnilateral\nAPC 87.5 97.8 87.5 97.8 96.4 0.854\nPPC 90 100 100 77.3 92.5 0.820\nBilateral\nAPC 77.7 100 100 79.1 82 0.514\nPPC 93.3 100 100 58.3 93.9 0.705\nSize\n≥ 48 mm\nAPC 53.8 100 100 87.8 89.3 0.642\nPPC 92.8 100 100 68.8 93.8 0.779\n< 48 mm\nAPC 63.6 97.4 87.5 90.2 89.8 0.675\nPPC 91.1 100 100 72.2 92.8 0.794\nAbbreviations: APC, anterior pelvic compartment; DIE, deeply infiltrating endometriosis; NPV , negative predictive value; OE, ovarian endometrioma; PPV , positive pre-\ndictive value; PPC, posterior pelvic compartment.\nendometriosis; however, TVS could still detect DIE or even\nPOD obliteration with acceptable accuracy in cases with-\nout OE. There was an acceptable agreement between TVS\nand laparoscopic findings for different DIE features and\nsites of involvement. The current findings are consistent\nwith the results of other studies (21) and underscore the ac-\ncuracy of TVS to detect pelvic endometriosis.\nDiagnosis of USL endometriosis using TVS has always\nbeen a major challenge in clinical practice, as it is strongly\nrelated to the sonographer’s experience and diagnostic\nmethod (22). Consequently , there are disputes over the\nsensitivity (and to a lesser extent specificity) of TVS for de-\ntecting USL endometriosis. Some studies reported a low\nsensitivity for TVS to demonstrate DIE in USL (4, 18, 23-25),\nwhereas some others, similar to the current research, con-\ncluded that TVS is highly sensitive for the detection of USL\nendometriosis (22, 26). Generally , anatomic complexities\n(especially in patients with pelvic adhesion/POD obliter-\nation) and a small lesion size can lead to underdiagno-\nsis. However, clinical awareness, professionally trained op-\nerators, and certain diagnostic methods (i.e., tenderness-\nguided methods and standoff techniques for near-field ar-\neas) may increase the detection rate (24, 27).\nThe ovarian mobility has been reported as the most\naccurate ultrasound indicator of pelvic adhesions, and\novarian/uterine mobility is acceptable for diagnosing en-\ndometriosis (6, 24, 28). This observation confirms the cur-\nrent results, although laparoscopic visualization was more\npromising in the present study . Transvaginal sonography\nhas been shown to be a promising modality for detect-\ning pelvic adhesions and POD obliteration (28-30), which is\nconsistent with our findings. Additionally , some studies re-\nIran J Radiol. 2022; 19(4):e127068. 7\n\nSadighi N et al.\nported a high level of TVS-laparoscopy agreement for ovar-\nian adhesions that are either mobile or fixed on palpation.\nSome studies suggested that TRS may improve the de-\ntection rate of DIE (23, 31, 32) and can help diagnose en-\ndometriosis in the intestines (6, 8, 33, 34). On the other\nhand, Bazot et al. compared the diagnostic yield of TVS\nand TRS in patients with pelvic endometriosis and demon-\nstrated that TVS was very accurate in identifying intesti-\nnal and bladder endometriosis (23). Generally , tubal block-\nade and the resulting dilatation (presenting as either hy-\ndrosalpinx or hematosalpinx) are common in DIE and con-\ntribute to infertility (35). In the present study , a similar de-\ntection rate was reported for hydrosalpinx/hematosalpinx\non TVS and laparoscopy . Based on the current results,\nperitoneal cysts were more frequently identifiable on la-\nparoscopy compared to TVS. Likewise, peritoneal cysts\nwere not significantly associated with a higher DIE detec-\ntion rate on TVS (36).\nConsidering the high accuracy of TVS for diagnosing\nDIE in challenging sites, such as distal ureter, bladder base,\nand upper and lower rectum, which may not be readily ac-\ncessible during laparoscopy , besides the unique applicabil-\nity of this modality for the examination of uterine/ovarian\nmotility , it may be even more advantageous for some cases.\nAdditionally , TVS has been shown to be more accurate in\nidentifying DIE lesions in patients with a minimal or mild\ndisease or when lesions are atypical in terms of morphol-\nogy , although they may appear normal on laparoscopy\n(36).\nPrecise diagnosis and mapping of DIE can greatly help\nwith treatment or surgical planning (if necessary), thereby\nreducing the risk of underestimation and incomplete ex-\ncision of DIE foci and obviating the need for multiple sur-\ngical procedures (since non-excised residual lesions tend\nto grow overtime and involve the adjacent structures) (37,\n38). Accurate DIE mapping may suggest the important\nrole of other specialists when bowel, distal ureter, or blad-\nder involvement is detected. Additionally , with an accu-\nrate estimation of the disease extent, clinically relevant\nDIE deposits are more likely to be localized and excised.\nMoreover, preoperative DIE mapping enables surgery cus-\ntomization, which may preclude complex adhesiogenic\nsurgeries.\nThe present study had some limitations. First, a small\npopulation for each site of involvement may cause sam-\npling bias. To obtain representative samples for each sub-\ngroup, comprehensive studies on larger populations or\npooling data from different studies are required. Sec-\nond, pelvic adhesion assessment can be deemed subjec-\ntive; however, the current study and some other investi-\ngations showed that it is accurate enough to be incorpo-\nrated into daily clinical practice (18). Third, this study did\nnot include asymptomatic cases of DIE, and the results can-\nnot be generalized to all patients. Collection of relevant\ndata from women undergoing exploring laparoscopy or\nlaparoscopy for any other indication, while paying atten-\ntion to the common sites of DIE plaque deposition may\nyield different findings and is encouraged in future inves-\ntigations. Finally , only TVS-positive cases were included in\nthis study , which might cause selection bias, whereas TVS-\nnegative cases (milder forms of pelvic DIE) who may show\nDIE on laparoscopy were not included; this can influence\nthe agreement of TVS and laparoscopic findings for some\nsites, if not all; nevertheless, nodules which are missed on\nTVS tend to be smaller and easier to excise, with a lower\nrisk of iatrogenic trauma in the bladder, ureters, and bowel\nwall (27).\nIn conclusion, the current findings showed that TVS\nis an accurate and non-invasive tool for detecting and\nmapping DIE and POD obliteration, regardless of the pres-\nence of OE, tubal dilation, or pelvic cysts and adhesions.\nTransvaginal sonography can be regarded as a useful tool\nfor identifying DIE preoperatively , as it may waive the need\nfor exploratory or confirmatory laparoscopy in DIE or at\nleast facilitate precise pre-procedural DIE mapping, be-\nsides the prediction of surgical difficulties, surgery dura-\ntion, postoperative complications, and length of hospital\nstay .\nFootnotes\nAuthors’ Contributions: B. M., N. S., M. G., and J. A. pro-\nvided guidance for the preparation of this manuscript.\nB. M., N. S., M. G., B. B., F. D. T., and R. D. collected the\ndata. B. B., R. D., and J. A. analyzed and interpreted the\ndata and drafted the manuscript. All authors reviewed the\nmanuscript, made significant revisions, and approved the\nfinal version of the manuscript.\nConflict of Interests: N. S., B. M., and M. G. are editorial\nboard members and faculty members of Tehran University\nof Medical Sciences. Also, B. B. and F. D. T. are faculty mem-\nbers of Tehran University of Medical Sciences.\nData Reproducibility: The dataset presented in this\nstudy is available on request from the corresponding au-\nthor during submission or after its publication.\nEthical Approval: This study was approved under the\nethical approval code of IR.TUMS.MEDICINE.REC.1400.1191\n(link: ethics.research.ac.ir/EthicsProposalView .php?id =\n240212).\nFunding/Support: The authors received no financial sup-\nport for the research, authorship, and/or publication of\nthis article.\n8 Iran J Radiol. 2022; 19(4):e127068.\n\nSadighi N et al.\nInformed Consent: Written informed consent was ob-\ntained from all the participants.\nReferences\n1. Vercellini P, Vigano P, Somigliana E, Fedele L. Endometriosis: patho-\ngenesis and treatment.Nat Rev Endocrinol. 2014;10(5):261–75. [PubMed\nID: 24366116]. https://doi.org/10.1038/nrendo.2013.255.\n2. Sonavane SK, Kantawala KP, Menias CO. 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