{"paper_id":"a8a2b2f0-6f00-40bf-90bb-4ba951f2cc9f","body_text":"142\nEndometriosis in magnetic resonance imaging: essentials for radiologists \nand clinicians \nLaura M. Olarte-Bermudez1* , Ana M. Rendon-Garavito1 , Andres F . Herrera-Ortiz1,2 ,  \nSara Paris-Zorro1 , Diana Romero-Mayorga1  and Javier Romero-Enciso 1\n1Department of Radiologia, Fundacion Santa Fe de Bogota; 2Facultad de Medicina, Universidad del Bosque. Bogota, Colombia\nIN DEPTH REVIEW\n*Corresponding author:  \nLaura M. Olarte-Bermudez  \nE-mail: lauraolbe@unisabana.edu.co\n2696-8444 / © 2025 Federación Mexicana de Radiología e Imagen, A.C. Published by Permanyer. This is an open access article under the \nCC BY-NC-ND (https://creativecommons.org/licenses/by-nc-nd/4.0/).\nAvailable online: 10-10-2025\nJ Mex Fed Radiol Imaging. 2025;4(3):142 -153\nwww.JMeXFRI.com\nFEDERACIÓN MEXICANADE RADIOLOGÍA E IMAGEN, A.C\nJournal of the Mexican Federation of Radiology and Imaging\nOfficial Journal of the \nJournal of the Mexican Federation \nof Radiology and Imaging\nReceived for publication: 23-04-2025\nAccepted for publication: 15-09-2025\nDOI: 10.24875/JMEXFRI.25000008\nABSTRACT\nEndometriosis is a chronic disease, characterized by the growth and implantation of endometrial tissue outside the uterus,  \nusually in deep pelvic structures, often resulting in inflammation, fibrosis and pain. The ovaries, the uterosacral ligaments, the \nrectovaginal septum, and, less frequently, other parts outside of the pelvis such as the diaphragm and the sciatic nerve are \nfrequently affected. Timely diagnosis remains a challenge despite the high prevalence due to the heterogeneous clinical \npresentation. Magnetic resonance imaging (MRI), provides better resolution compared to other imaging modalities and helps \nidentify different forms of the disease, including superficial, deep infiltrative endometriosis (DIE) and endometriomas. This \nreview describes the recommended MRI protocol, descriptions of key imaging findings, the Deep Pelvic Endometriosis Index \n(dPEI) and the MRI consensus lexicon, and the ENDOVALIRM group's compartment-based approach an MRI-based system \nthat helps classify disease by severity and location for guiding clinical decisions, support preoperative planning and predict \nsurgical outcomes. According the compartment-based approach an MRI-based system, two horizontal lines divide the pel -\nvis into an anterior, a middle and posterior region. In addition, vertical lines divide the pelvis into a central, a left and a right \ncompartment. This anatomical framework creates 9 compartments: anterolateral, anteroventral, mediolateral, midcentral,  \nposterolateral, posterior-central with additional extrapelvic areas. This review aims to support radiologists and gynecology \nteams in the accurate detection and classification of endometriosis through standardized MRI interpretation, increasing \ndiagnostic confidence and contributing to better surgical and clinical outcomes.\nKeywords: Endometriosis. Magnetic resonance imaging. Deep pelvic endometriosis index. ENDOVALIRM group. MRI protocol.\nINTRODUCTION\nEndometriosis is a common chronic inflammatory dis-\nease, characterized by abnormal growth of endometrial \ntissue outside the uterus, which is usually benign but with \na heavy health burden. Ectopic endometrial tissue con -\nsists of normal endometrial stroma and glands that react \nto the hormonal changes that occur during the menstrual \ncycle. These periodic hormonal changes are associated \nwith cyclic bleeding, and fibrosis1. This condition occurs \nin approximately 5-10% of women of childbearing age, \nwith the global burden estimated to be around 176 million \nwomen worldwide. According to some studies, the  \nprevalence in some populations is as high as 20% of \nwomen2,4. Endometriosis is present in up to 90% of \npatients presenting with infertility and chronic pelvic pain. \nDespite this, around 65% of cases are misdiagnosed5,6.\nThere have been major advances in the detection  \nand characterization of different patterns and locations \nusing diagnostic modalities such as magnetic resonance \n\nL.M. Olarte-Bermudez et al.  Endometriosis in MRI\n143\nimaging (MRI). However, timely and accurate diagnosis \nof endometriosis remains a challenge as the disease \npresents very differently in terms of both symptoms and \nimaging findings5. This contributes to the fact that it typ -\nically takes 10 years between the onset of symptoms \nand diagnosis, with most women seeing 3 or more doc -\ntors and healthcare professionals before receiving the \ncorrect diagnosis. Typically, the diagnosis is not made \nuntil the fourth decade of life, although symptoms usually \nbegin in the early twenties 6. In light of these cases, this \nreview compiles updates for radiologists, trainees, and \ngynecologists to take a better approach to endometriosis \nby introducing a standardized scale that allows radiolo -\ngists to appropriately communicate their findings to \ngynecologists.\nNORMAL GYNECOLOGICAL ANATOMY\nThe uterus is a pear-shaped reproductive organ located \nin the female pelvis between the rectum in the posterior \nregion and the bladder in the anterior region. This organ \ncan be divided into three main segments: the fundus, the \nbody and the cervix. The body and the fundus are mostly \ncomposed of the myometrium, the main muscle layer, \nwhich is made up of layered and interwoven smooth \nmuscles interspersed with arterioles, nerves and areolar \ntissue, which ensures their contractile function and better \nstructural integrity. Distally, the uterine body narrows, and \nopens into the vagina via the cervical canal. The fibers \nof the outer layer of the body and the fundus are arranged \ntransversely and continue into the surrounding structures, \nincluding the fallopian tubes, the round ligament and the \novary ligament7. The uterus is covered on the outside by \nthe serosa, a thin layer derived from the peritoneum. \nInside, the uterine cavity is lined by the endometrium, an \nepithelial stroma containing tubular endometrial glandular \ntissue, that changes cyclically with the phases of the \nmenstrual cycle8. In approximately 80% of women, the \nuterus is in anteversion. \nAbove and anteriorly, the peritoneum covers the  \nuterine body and the bladder and forms the vesico-  \nuterine pouch. Posteriorly, the peritoneum covers the \nfundus, the cervix and the upper part of the vagina, and \nform the rectouterine pouch, also known as the Douglas \npouch. On MRI, the endometrium can be visualized  \nas a hyperintense structure on T2-weighted images  \nand shows homogeneous, low-signal, non–contrast-  \nenhanced T1-weighted imaging 7.\nThe cervix, which acts as a connecting duct between \nthe uterine cavity and the vagina, normally measures \napproximately 4 cm in length and 3 cm in diameter in \nnon-pregnant women. On high-resolution T2-weighted \nMRI of the pelvis, the cervix can be differentiated into three \nzones: a central hyperintense zone formed by the endo-\ncervical mucosa, a hypointense middle layer, and an outer \nlayer with low to moderate signal intensity, both consisting \nof fibromuscular stroma9. A unique anatomical structure \nthat requires special attention is the uterine torus, a small \ntransverse thickening in the posterior part of the cervix \nwhere the uterosacral ligaments converge10. \nThe broad ligament, a lateral peritoneal fold that  \nsurrounds the fallopian tubes, is the most important of \nthe various ligamentous structures that support the \nuterus. The fallopian tubes consist of 5 anatomically \ndifferent segments: The intramural portion, the isthmus, \nthe ampulla, the infundibulum, and the fimbriae, which \nare finger-like projections connected to the ovaries 8. \nThe ovaries are ovoid organs, that are normally  \nhave a volume of 6-7 ml in premenopausal women. \nHowever, great variability can occur. They are located \nin the ovarian fossa, are supported by several ovarian \nligaments and are connected to the fallopian tubes  \nvia the fimbriae. On MRI, the ovarian cortex appears \nhypointense on T2-weighted images, while the medulla \nshows intermediate to high signal intensity, reflecting its \nvascular and stromal composition 7.\nPATHOGENESIS AND CLINICAL \nMANIFESTATIONS\nDespite continuous research, the exact etiology and \npathophysiology of endometriosis are still not fully \nunderstood, which significantly hinders the develop -\nment of definitive curative therapies. Several environ -\nmental, immunologic, genetic and endocrine risk fac tors \nhave been identified, including short menstrual cycle \nduration, young age at menarche, low body mass index, \nnulliparity and congenital obstructive müllerian defects11. \nExposure to certain toxins such as bisphenol A and \nphthalates, alcohol consumption and low physical activ -\nity have also been associated with an increased risk of \nthis condition 12. Some studies also suggest a familial \npredisposition, with twin studies showing a 50% herita -\nbility and an increased risk (3-15 times) in first-degree \nrelatives with the disease 13–15. Among the proposed \nmechanisms, the most widely accepted theory for  \nthe pathogenesis of endometriosis is the “retrograde \nmenstrual phenomenon”. This theory proposes that \nfragments of the endometrium migrate through the  \nfallopian tubes into the peritoneum, implant, grow and \ninvade the pelvic structures, leading to inflammation  \nand fibrosis. In addition, it has been suggested that \n\nJ Mex  Fed  Radiol  iMaging . 2025;4(3):142-153\n144\nhematogenous and lymphatic dissemination of endome-\ntrial cells may be a mechanism for the occurrence of \nectopic lesions in distant organs 16,17. \nThere are various forms of the disease, including \nsuperficial peritoneal endometriosis, deep infiltrative \nendometriosis (DIE) and endometriomas. The clinical \nmanifestations of patients with endometriosis vary \ndepending on the location of the disease. Superficial \nperitoneal endometriosis is usually characterized by \nbeing asymptomatic, while DIE is associated with pelvic \npain, dysmenorrhea, dyspareunia, urinary symptoms \nand infertility 18. Studies have shown that there is no \ndirect correlation between the severity of symptoms \nand the extent of impairment of the lesion, as some \npatients with full-blown disease are unaware of their \ncondition, adding to the mystery of the disease 19. It  \nis important to consider the sensory innervation of \nendometriotic lesions, as deeply infiltrating lesions can \naffect nerve fibers, resulting in current pain 18. \nThe definitive diagnosis of endometriosis should be \nmade by laparoscopy. Histologic examination of the \nbiopsied tissue should show ectopic endometrial glands \nand stroma20. However, several international guidelines \nrecommend a more conservative, image-based initial \napproach. Transvaginal ultrasound (TVUS) is conside -\nred the imaging technique of choice due to its easy \naccessibility and low cost. MRI is a very useful tool for \ndiagnosis and preoperative planning as it offers better \ncontrast resolution, and more detailed anatomy. With \nan overall sensitivity of 91% to 93.5% and a specificity \nof 86% to 87.5%, it is an excellent tool for diagnosis, \nmapping and preoperative planning 11. \nThe anatomical forms of presentation such as super -\nficial peritoneal endometriosis, DIE and endometriomas \nshow different imaging findings 21. Endometriomas are \ncystic lesions of the ovary characterized by high T1 \nsignal intensity and intermediate T2 signal intensity \nwith the classic shading appearance, reflecting hemor -\nrhagic content and cyclic blood breakdown. Several \nimaging signs have been described in large endome -\ntriomas. One of the most common signs is the “kissing \novary” sign, in which periovarian adhesions pull the \novaries together near the midline 22. Another feature of \nendometriomas is the double level of fluid– inside the \nendometrioma, indicating blood in various stages of \ndegradation within the endometrioma 17.\nAcute endometriosis lesions shows high T1 signal inten-\nsity but with variable T2 signal due to different bleeding \nand glandular contents. Chronic or fibrotic endometriosis \nshows low signal intensity on both T1 and T2, indicating \nreplacement of active tissue with fibrosis and scar tissue.\nMULTIMODALITY IMAGING FOR \nENDOMETRIOSIS\nEndometriosis requires imaging as a fundamental \ntool for diagnosis, disease monitoring, and preoperative \nplanning. TVUS is the imaging modality of choice for \nthe evaluation of suspected endometriosis because it \nis easily accessible, does not require ionizing radiation, \nhas high diagnostic accuracy, and is cost-effective 23. \nFurther advantages are the possibility of real-time \nassessment and its non-invasive nature 23.\nThe diagnostic performance of TVUS varies depending \non the type and location of endometriotic lesions. A 2016 \nCochrane review, which included 17 studies reported a \nsensitivity of 93% and specificity of 96% for the detection \nof endometriomas in the ovaries, while the sensitivity for \nDIE, was 79% and specificity 94%. Recent guidelines \nfrom the European Society of Human Reproduction and \nEmbryology (ESHRE) recommend that imaging tech -\nniques, especially TVUS, should replace diagnostic lap-\naroscopy as the first line of investigation due to the \nadvantages mentioned above. Accordingly, laparoscopy \nis now reserved for cases where imaging is inconclusive \nor when therapeutic intervention is planned.\nExpert-guided transvaginal ultrasound (ETVUS) is \ndefined as a dynamic real-time ultrasound examination \nperformed by a clinician with expertise in endometriosis. \nIt has been shown to improve detection rates and pro -\nvide better information for preoperative assessment of \nthe extent of disease24. ETVUS has a sensitivity of 77.5% \nfor deep endometriosis, comparable to a sensitivity of \n78.5% reported by Bazot et al.11 in similar cohorts 24.\nContrast-enhanced ultrasound (CEUS) has become \na complementary method in some selected cases. \nCEUS provides a better imaging approach to charac -\nterize endometriotic lesions by using microbubble con -\ntrast agents to assess tissue perfusion and vascular \narchitecture in real time, especially in differentiating \nsolid endometriotic implants from other adnexal or pel -\nvic masses 25. Endometriotic nodules may have differ -\nent enhancement patterns, typically showing moderate \nto low vascularity due to associated fibrosis and chronic \ninflammation. CEUS may also be helpful to detect vas -\ncular involvement in DIE or to guide targeted biopsies \nof atypical or suspicious lesions 25.\nMRI ENDOMETRIOSIS PROTOCOL\nThe literature has shown that the MRI protocol for \nendometriosis should be performed in a superconducting \n1.5T (Tesla) system26. An axial and sagittal T2 single-shot \n\nL.M. Olarte-Bermudez et al.  Endometriosis in MRI\n145\nfast spin echo (SSFSE) sagittal plane aligned parallel to \nthe longitudinal axis of the uterus. In addition, the exam-\nination requires an oblique coronal and oblique axial \nT2-weighted Fast Recovery Fast Spin Echo (FRFSE) \nsequence26. T2-weighted sequences without fat suppres-\nsion are the preferred sequences for detecting pelvic \nendometriosis, as they are considered the most effective \nmethod due to their superior anatomical delineation and \nsensitivity to fibrotic changes26.\nIn order to maximize the quality of the diagnostic \nmethod, preparation for the examination is crucial. We \nrecommend that patients fast for approximately 4-6 \nhours prior to MRI and undergo bowel preparation to \nreduce peristaltic artifacts. In addition, the examination \nshould be performed outside the patient’s menstrual \ncycle, as this can be a confounding factor26. In our insti-\ntution, the protocol indicates the use of antispasmodic \ndrugs (glucagon or hyoscine) to minimize bowel peri -\nstalsis. We also ask patients to keep the bladder full  \nto detect endometriosis lesions near the bladder. An \nendovaginal gel is also inserted to dilate the vaginal \ncanal and improve the view of the adjacent structures. \nTable 1 shows the MRI protocol at our institution: cor -\nonal T2-weighted images covering the entire pelvis  \nand extending from the lesions of the kidneys to the \npelvic floor; axial, sagittal, and coronal T2-weighted \nimages; axial T1-weighted in-phase and out-of-phase \nimages; coronal T1-weighted fat-saturated images  \nwithout contrast; and post-contrast T1-weighted fat-  \nsaturated images acquired in the axial, coronal, and \nsagittal planes.\nSeveral authors 18,27,28 have proposed improved MRI \nprotocols specifically designed for the detection of DIE. \nThese protocols include T2-weighted images without \nfat suppression in the axial, coronal, and sagittal planes \nfor a clear view of the round ligaments and pelvic \nregion27,28. The protocols also recommend T1-weighted \nimages with fat-suppression to detect hemorrhagic foci \nsmaller than 1 cm. T2-weighted fat-suppressed images, \neither in the axial or coronal plane, help to better iden -\ntify small amounts of free fluid adjacent to lesions 28. \nGadolinium contrast agent is generally discouraged as \nthere is currently insufficient evidence of its significant \nadded benefit 18.\nENDOMETRIOSIS LOCATIONS BY \nCOMPARTMENTS \nEndometriosis in the anterolateral \ncompartment: round ligament\nThe round ligament is part of the upper edge of the \nbroad ligament, which is covered by a peritoneal fold. \nIts main anatomical function is to support the uterus by \nanchoring it to the mons pubis and labia majora via the \ninguinal canal. This canal obliterates physiologically \nbetween the eighth month of gestation and the first \nTable 1. MRI 1.5T and 3.0T protocol for the assessment of endometriosis\nField  \nstrength\nSequence FOVa mm Matrix TR ms TE ms Flip angle, \ndegrees\nSlice thickness, \nmm\n1.5T Cor T2 FSE panoramic 40 × 60 468 × 468 9480 136 140 4\nAxial Dual Echo 43 × 1 288 × 160 120 2.2 85 4\nAxial DWI 40 × 40 112 × 128 8270 72 - 4\nSag T2FSE spin eco 20 × 20 300 × 224 7.2 120 140 3\nCor T2 FSE 20 × 20 300 × 224 7.2 120 110 3\nT1 LAVA 3D Sag 24 × 24 300 × 176 7.5 2.1 12 2.2\n3.0T Cor T2 PROPELLER 20 × 20 320 × 320 442 112 111 5\nSag T2 FRSE 20 × 20 320 × 200 442 54.6 110 3\nAxial T2 FRSE 20 × 20 320 × 256 5510 112 100 3\nDWI 34 × 34 80 × 128 5510 112 - 5\nDual Eco 36 × 36 240 × 140 5510 112 - 5\nLAVA 2D Sag 24 × 24 188 × 128 112 112 12 2.30 × 1.03\naVaries according to the width of the patient’s pelvis. MRI: magnetic resonance imaging; T: tesla; TI: time inversion; FOV: field of view; TR: \ntime repetition; TE: time echo; ms: milliseconds; FSE: fast spin echo; FRSE: fast recovery spin echo; DWI: diffusion-weighted imaging; LAVA: \nliver acquisition with volume acceleration; 3D: three-dimensional; 2D: two-dimensional; PROPELLER: periodically rotated overlapping parallEL \nlines with enhanced reconstruction; Sag: sagittal; Cor: coronal.\n\nJ Mex  Fed  Radiol  iMaging . 2025;4(3):142-153\n146\npostnatal year. This ligament also helps to maintain the \nanteversion of the uterus throughout the reproductive \nperiod. The round ligament is a 10-12 cm long cord-like \nstructure, composed of fibromuscular tissue. It is con -\nsidered clinically relevant to endometriosis due to its \nanatomical proximity to the fallopian tubes, vessels, \nand nerves contained within the broad ligament 29,30. \nOn MRI, it usually appears as a thin, generally \nsmooth, hypointense structure on T1- and T2 weighted \nimages, extending from the uterine horns to the pelvic \nwall and running anterior to the external iliac vessels, \nwhich are highlighted by the surrounding fat.\nEndometriosis of the round ligament is rare, with an \nestimated incidence of 0.3% to 0.6% of cases, most of \nwhich occur in the extrapelvic region and on the right \nside. Signs and symptoms may vary depending on the \nlocation of the lesion, with pain usually localized to the \nlower abdomen31. Endometriotic involvement may cause \nasymmetric thickening, typically larger than 1 cm, with \neither a smooth or nodular morphology. The segment \nadjacent to the uterus is most commonly affected. Figure \n1 shows an MRI of the pelvis of a 44-year-old woman \nwith pelvic pain associated with the perception of a mass \nin the right groin. T2-weighted images show a poorly \ndefined heterogeneous lesion in the right inguinal canal \nthat is predominantly hypointense. There are also irreg -\nular fibrotic bands with blurred borders suggestive of \nendometriotic infiltration. Hyperintense foci suggestive \nof blood content are seen on the T1-weighted fat-sup -\npressed sequences without contrast.  The MRI findings \nare consistent with the diagnosis of endometriosis of \nthe right inguinal canal.\nEndometriosis of the round ligament exhibits variable \nMRI signal characteristics depending on the composi -\ntion of the lesion, including stromal tissue, glandular \nelements, hemorrhage, inflammatory reaction, or fibro -\nsis. Purely fibrotic lesions appear hypointense on both \nT1- and T2-weighted images, whereas hemorrhagic foci \nshow hyperintensity on T1-weighted and/or fat-sup -\npressed T1-weighted sequences. However, lesions are \nusually a mixture of both components and visual sur -\ngical findings such as shortening, deviation or thicken -\ning of the round ligaments of the uterus (RLUs) have a \nhigh positive predictive value (83.3%) for the diagnosis \nof endometriosis in these ligaments; these findings may \nfacilitate the decision to excise these ligaments 18. \nAlthough the prevalence of endometriosis in RLUs is \nnot as high as in other structures, endometriosis in \nRLUs may have clinical implications for the persistence \nof postoperative symptoms, as comprehensive resec -\ntion of all visible lesions increases the likelihood of \nimprovement in symptoms and quality of life 32,33.\nEndometriosis in the anteroventral \ncompartment: bladder \nBladder endometriosis is the most common form of \nurinary tract involvement in endometriosis, and accounts \nfor about 70% to 85% of genitourinary cases. However, \nonly 1% of cases present with isolated urinary tract \nfoci33,34. This form of the disease is clinically significant \nas it is associated with chronic, often debilitating symp -\ntoms such as dysuria, hematuria, increased urinary \nfrequency, and voiding dysfunction. Therefore, timely \nFigure 1. MRI of the pelvis of a 44-year-old woman with pelvic pain associated with the perception of a mass in the right groin. A: axial view, \nT2-weighted sequence shows a round, poorly defined predominantly hypointense lesion, and to a lesser extent, multiple small hyperintense \nregions, giving a heterogeneous appearance (white arrow). B: axial T1-weighted sequence with fat suppression, without contrast, shows \nhyperintense foci within the endometrial lesion (white arrow), representing a blood component. C: sagittal T2-weighted view shows fibrotic \nbands, with poorly defined borders (white arrow), involving the right inguinal canal. The MRI findings are consistent with the diagnosis of \nendometriosis of the right inguinal canal.\nMRI: magnetic resonance imaging.\nA B C\n\nL.M. Olarte-Bermudez et al.  Endometriosis in MRI\n147\nTVUS, especially in combination with transabdominal \nviews and bladder filling, can also help to detect endome-\ntriomas. This technique may reveal hypoechoic mural \nnodules or irregularities along the bladder dome or pos -\nterior wall. In some cases, loss of the normal interface \nbetween the posterior bladder wall and the anterior uter-\nine surface may serve as an additional clue. Cystoscopy \ncan be used to confirm mucosal involvement and rule  \nout malignancy, although it is of limited use in detecting \nlesions outside the mucosa. Accurate identification of \nbladder endometriosis is critical for planning surgical inter-\nvention, as complete resection or partial cystectomy may \nbe required to improve symptoms, particularly in inva -\nsive disease that is unresponsive to medical therapy.\nEndometriosis of the middle central \ncompartment: uterosacral ligament\nThe uterosacral ligaments are paired fibromuscular \nstructures that extend from the posterolateral cervix \nand upper vagina to the anterior aspect of the sacrum, \nproviding important support to the uterus and main -\ntaining pelvic floor the stability. These ligaments are \ncommonly affected in DIE, which often involves the \nmid-central compartment of the posterior pelvic cavity. \nDIE is defined as invasion > 5 mm of the peritoneal \nsurface by endometriotic lesions, most commonly \nlocated at the uterosacral ligaments, rectovaginal \nspace, pararectal space and vesico-uterine fold 35.\nimaging is required for diagnosis, as it may be associa -\nted with the risk of renal failure due to urinary tract \nobstruction. \nIn bladder endometriosis, MRI typically shows locali -\nzed or diffuse wall thickening with associated signal \nabnormalities. Findings include nodular thickening with \nT2-weighted low signal intensity fibrotic stranding; \nsometimes, hyperintense hemorrhagic foci may be \npresent in T1-weighted sequences. Figure 2  shows an \nMRI of the pelvis of a 45-year-old woman with hypo -\ngastric pain and dysmenorrhea, who had undergone a \nhysterectomy. On coronal T2-weighted images, the \nlesion extends to the bladder serosa and infiltrates the \nanterior perivesical fat in the Retzius space. On sagittal \nT2-weighted images, an irregular, predominantly \nhypointense lesion is seen at the level of the bladder \ndome with distention of the vagina due to the use of \nintravaginal gel. On T1-weighted images without fat \nsuppression, the lesion is hypointense and pseudono -\ndular, whereas contrast-enhanced T1-weighted images \nwith fat suppression show heterogeneous hyperinten -\nsity due to contrast uptake, The MRI findings are con -\nsistent with the diagnosis of DIE involving the bladder. \nIn most cases, lesions are confined to the serosal layer \nof the bladder, although extension into the muscularis \npropria may occur in advanced disease. The mucosa \nin particular is often spared, which may result in cys -\ntoscopy showing normal findings despite significant \nextramucosal disease.\nFigure 2. MRI of the pelvis of a 45-year-old woman with hypogastric pain and dysmenorrhea, who had a history of hysterectomy. A: coronal \nT2-weighted MRI shows a poorly defined, pseudonodular lesion in the anterior bladder wall (white arrow), extending to the bladder serosa \nand infiltrating the anterior perivesical fat (space of Retzius). B: sagittal T2-weighted MRI shows an irregular, predominantly hypointense \nlesion (white arrow) involving the bladder dome. The distended vagina is visible due to the presence of intravaginal gel. C: T1-weighted \nimage without fat suppression showing a hypointense, pseudonodular lesion in the anterior bladder wall (white arrow). D: contrast-enhanced \nT1-weighted image with fat suppression shows a pseudonodular lesion of the bladder wall, that appears hyperintense due to contrast uptake \n(white arrow). The MRI findings are consistent with the diagnosis of DIE involving the bladder.  \nDIE: deep infiltrative endometriosis; MRI: magnetic resonance imaging. \nA B C\nD\n\nJ Mex  Fed  Radiol  iMaging . 2025;4(3):142-153\n148\nThe most common site of DIE is the uterosacral lig -\naments, which are affected in up to 70% of cases 36. \nThe differential diagnosis of ureteral endometriosis \nincludes ureteral invasion by cervical cancer. On MRI, \nthe main findings are asymmetric shortening, thicken -\ning, and nodularity involving the ligaments 37. Figure 3 \nshows an MRI of the pelvis of a 32 -year-old woman \nwith pelvic pain and dysmenorrhea. The axial T2- \nweighted image shows smooth thickening of the right \nuterosacral ligament. The MRI findings are consistent \nwith the diagnosis of DIE in the uterosacral ligament.\nImpairment of the uterosacral ligament typically  \npresents as fibrotic thickening with low signal on T2- \nweighted images, which may be spiculated, nodular, or \nsmooth. In some cases, focal areas of high signal inten-\nsity may be present on T1-weighted images, suggesting \nhemorrhagic components. Although specific diameter \nthresholds have been proposed for the diagnosis of \nendometriosis of the uterosacral ligament, these are \nnot yet well validated 37.\nEndometriosis of the posterolateral \ncompartment: rectovaginal septum\nEndometriosis of the rectovaginal septum is a serious \ncondition with clinical manifestations such as abdominal \npain, colonic obstruction, and, in some cases, renal \nobstruction. The diagnostic difficulty of multifocal endo -\nmetriosis begins with its similarity to other pathologies38. \nDeep dyspareunia, dyschezia, and chronic pelvic pain \nare common symptoms that intensify during menstrua -\ntion. In some cases, rectovaginal endometriosis may \nmimic irritable bowel syndrome, inflammatory bowel dis-\nease, or pelvic inflammatory disease, leading physi -\ncians to misdiagnose. A thorough clinical history, with \nparticular attention to cyclical symptoms, is crucial to \nraise suspicion and prompt appropriate referral for \nimaging and avoid unnecessary surgery 21,39.\nA meta-analysis found that the sensitivity and spec -\nificity of MRI for the diagnosis of rectovaginal septal \nendometriosis were 82% and 77%, respectively. On \nMRI, rectovaginal endometriosis may present as ill-  \ndefined lesions, soft tissue thickening, or obliteration of \nthe pouch of Douglas. On MRI these lesions typically \nshow low signal intensity on T1- and T2-weighted \nimages with late contrast enhancement due to the \nfibrotic component 40,41. Occasionally, punctate hyperin -\ntense foci may be present on T1-weighted images, \nindicating subacute hemorrhage or highly viscous fluid. \nFigure 4  shows an MRI of the pelvis of a 39-year-old \nwoman with chronic pelvic pain, constipation and \nFigure 3. MRI of the pelvis of a 32 -year-old woman with pelvic pain \nand dysmenorrhea. The axial T2-weighted image shows smooth \nthickening of the right uterosacral ligament (white arrow). The MRI \nfindings are consistent with the diagnosis of DIE in the uterosacral \nligament.\nDIE: deep infiltrative endometriosis; MRI: magnetic resonance imaging.\ndyspareunia. Sagittal T2-weighted images show irregu -\nlar, hypointense lesions involving the rectovaginal sep -\ntum, with a distended vagina visible due to the presence \nof intravaginal gel. The MRI findings are consistent with  \nthe diagnosis of DIE involving the rectovaginal septum.\nAlthough MRI is superior to other imaging modalities \nin the overall visualization of the pelvis, its diagnostic \naccuracy in the detection of superficial peritoneal lesions \nis limited. In this context, laparoscopy remains the gold \nstandard for the diagnosis of superficial endometriosis \nand is more accurate than MRI, TVUS or physical  \nexamination for this particular subset of lesions 40.\nEndometriosis of the posterior-central \ncompartment: rectosigmoid colon\nDeep endometriosis is an entity that poses a challenge \nfor the gynecologist. The rectosigmoid colon is most \ncommonly affected by intestinal endometriosis, which \nmainly affects the central posterior compartment (65.7%). \nIn the rectum, it usually affects the middle and upper third \nof the organ 39. On MRI, endometriosis appears as T2 \nhypointense thickening of the muscle layer, ranging from \nplaque-like involvement to nodular, mass-like lesions. A \nclassic sign of rectal involve ment is the ‘mushroom cap’ \nappearance, caused by T2-hypointense fibromuscular \nhypertrophy of the muscularis, with wrinkling and retrac-\ntion of the serosa or adventitia resembling the appear -\nance of a mushroom. Figure 5 shows an MRI of the pelvis \nof a 40-year-old woman with pelvic pain and rectal bleed-\ning during menstruation. a lesion of the mucosa of the \n\nL.M. Olarte-Bermudez et al.  Endometriosis in MRI\n149\nmid-rectum with thickening of the muscularis propria, \nforming the mushroom cap sign. The axial and sagittal \nT2-weighted MRI images show the finding of this mush-\nroom cap lesion is a reliable predictor of infiltration of the \nmuscularis. The MRI findings are consistent with the \ndiagnosis of DIE with involvement of the rectosigmoid \ncolon and show the mushroom cap sign. \nA typical imaging finding for sigmoid involvement is the \n‘fortune cookie’ sign, which appears as a T2-weighted \nmass with low signal intensity, central retraction, and \ndelayed homogeneous enhancement that resembles the \nappearance of a fortune cookie. T1-hyperintense foci cor-\nresponding to hemorrhagic components can also be \nobserved in the fortune cookie and mushroom cap sign42. \nAssessment of rectal segments, classified as low (< 5 cm), \nmiddle (5-10 cm), and high (> 10 cm) from the anal verge \nis essential when assessing the anal margin42.\nExtrapelvic endometriosis: diaphragmatic \nand perihepatic\nExtrapelvic endometriosis is rare and has several local-\nizations, such as the abdominal, thoracic and hepatic \ncapsule. The most common location of thoracic endome-\ntriosis is the diaphragm, with an incidence of 0.15% to \n1.5%, followed by the pleura and lung 41. Diaphragmatic \nendometriosis can manifest clinically as catamenial or \nnon-catamenial pneumothorax. Initial imaging modalities \ninclude chest X-ray and computed tomography (CT); \nhowever, MRI provides better imaging, with a reported \nsensitivity of 78% and specificity of 83% 41,43.\nA catamenial pneumothorax is defined as a pneumo -\nthorax occurring three days before or after menstrua -\ntion. It accounts for 3-6% of spontaneous cases in \nwomen and is associated with endometriotic diaphrag -\nmatic foci extending into the thorax. These foci can \nirritate and perforate the pleura. Endometriotic nodules \nare found in 78% of catamnestic cases. This disease \nmainly affects the right side (90%) 43. \nThe main challenge in the diagnosis of diaphragmatic \nendometriosis is its potential rarity, in addition to its \nasymptomatic nature, which can reach almost 70% of \ncases44. When symptomatic, it manifests by pain in the \narm, shoulder or right upper quadrant and is often diag -\nnosed incidentally during surgical procedures, although \nthe exact mechanism is still unclear 45. Some theories \nsuch as retrograde menstruation, hematogenous spread, \nlymphatic dissemination, and coelomic metaplasia have \nbeen proposed as possible causes 46. \nOn MRI, endometrial foci may appear hyperintense \nin all sequences. Figure 6 of an abdomino-pelvic MRI \nof a 36-year-old woman with dyspareunia, and dysmen-\norrhea and cyclic right upper quadrant pain shows a \nsubcapsular lesion with intermediate signal intensity and \ninternal hypointense septa on T2-weighted images. On \nT1-weighted fat-suppressed (LAVA) sequences, a  \nhyperintense nodule within the lesion suggests an  \nendometrioma with blood derivatives. Post-contrast \nFigure 4. MRI of the pelvis of a 39-year-old woman with chronic pelvic pain associated with constipation and dyspareunia. A-B: sagittal  \nT2-weighted MRI shows irregular, hypointense lesions involving the rectovaginal septum (white arrows). The distended vagina is visible due \nto the presence of intravaginal gel. The MRI findings are consistent with the diagnosis of DIE involving the rectovaginal septum.\nDIE: deep infiltrative endometriosis; MRI: magnetic resonance imaging.\nA B\n\nJ Mex  Fed  Radiol  iMaging . 2025;4(3):142-153\n150\nT1-weighted imaging with subtraction shows heteroge -\nneous enhancement of the lesion. The MRI findings are \nconsistent with the diagnosis of extra pelvic extension \nof the endometriosis to the diaphragm and the perihe -\npatic region.\nSusceptibility artifacts in the thorax can lead to dis -\ntortions that obscure the diagnosis due to the proximity \nto the air in the lungs. Recognizing the typical linear \nshape, that runs parallel to the diaphragm, can be help -\nful in distinguishing true endometriosis lesions from \nartifacts47.\nExtrapelvic endometriosis: sciatic nerve\nIsolated, DIE of the sacral nerve roots or pelvic nerves \nsuch as the sciatic nerve is a rare entity that usually \ncauses back pain, buttock pain with radiation to the dor-\nsal region of the thigh and lateral aspect of the leg. \nPhysical examination may reveal a positive Lasegue’s \nsign, loss of sensation, reflex changes, muscle weak -\nness and paresis18. The sciatic nerve is rarely affected \nby endometriosis. It is usually a case of cyclic sciatica \nthat does not respond to the usual conservative treat -\nment48. Cyclic sciatica is a reactive, self-limiting inflam -\nmatory reaction to deposits and bleeding of endometrial \nglands and stroma in the sciatic nerve. \nEarly and timely diagnosis is essential, as untreated \nand unrecognized cases carry the risk of permanent \nneuronal damage if left untreated 27. Given the complex-\nity of the condition, treatment requires a multidisci -\nplinary approach, involving the specialties of gynecology, \northopedics, neurology and radiology. MRI and/or \nmyelography are of paramount importance for preoper -\native assessment, especially for the localization of the \nlesion, which must be confirmed by immunohistochem -\nistry22. A study by Kale et al. 42 showed that endometri -\nosis isolated to the sciatic nerve root is more commonly \nfound on the right side. \nMRI findings suggestive of neural involvement include \nneural thickening, abnormal signal intensity, and increased \nenhancement on contrast-enhanced MRI. Sciatic endo -\nmetriosis foci can be identified by the stage of hemor -\nrhage, as they typically have high signal intensity on \nT1-weighted images, and variable signal intensity on \nT2-weighted images49. Figure 7 shows an MRI of the \npelvis of a 36-year-old woman with chronic pelvic pain, \nand unilateral shooting pain that extended from the but -\ntock down to the posterior thigh, suggesting sciatic nerve \ninvolvement. Axial T2-weighted images show an ill-de -\nfined, spiculated, hypointense lesion in the right lateral \nwall of the pelvis with involvement of the sciatic nerve \nFigure 5. MRI of the pelvis of a 40 -year-old woman with pelvic pain associated with rectal bleeding during menstruation. A: sagittal and  \nB: axial T2-weighted MRI views show a lesion of the mucosa of the mid-rectum with thickening of the muscularis propria forming  \nthe mushroom cap sign (white arrows). The distended vagina and rectum are visible due to the presence of intravaginal and intrarectal gel. \nThe MRI findings are consistent with the diagnosis of DIE with involvement of the rectosigmoid colon and show the mushroom cap sign.\nDIE: deep infiltrative endometriosis; MRI: magnetic resonance imaging.\nA B\n\nL.M. Olarte-Bermudez et al.  Endometriosis in MRI\n151\nroots. The MRI findings are consistent with the diagnosis \nof DIE with sciatic nerve.\nIt is important to note that the absence of pelvic endo-\nmetriosis does not exclude the diagnosis of sciatic \nnerve endometriosis, which emphasizes the importance \nof high clinical suspicion in patients. In women of child -\nbearing age who complain of sudden sciatic symptoms \nthat correlate in time with the menstrual cycle and exac-\nerbation of symptoms, nerve involvement secondary to \nendometriosis should be considered 50. MRI is a helpful \ntool in determining the cause.\nENDOVALIRM group MRI consensus \nlexicon and compartment-based approach \nAccording to the ENDOVALIRM group, the pelvis can \nbe divided into 9 compartments based on important \nstructural landmarks 41. Two horizontal lines divide the \npelvis into an anterior, a middle and posterior region \n(Figure 8). The anterior horizontal line is drawn anterior \nto the cervix or vagina, while the posterior line is located \nanterior to the rectum. In addition, vertical lines divide \nthe pelvis into a central, left and right compartment. \nThese lines run from posterior to anterior, through the \nuterosacral ligament, the mesorectal fascia, the lateral \nwalls of the cervix and the bladder. This anatomical \nframework creates 9 compartments: right anterolateral, \nright mediolateral, right posterolateral, anterocentral, \nmediocentral, posterocentral, left anterior, left medial, \nand left posterior with additional extrapelvic areas 41.\nThe Deep Pelvic Endometriosis Index (dPEI) is an \nMRI-based system, developed for DIE, the aims to com-\nprehensively describe all localizations of deep endome -\ntriosis by creating structured reports with diagrams and \nscores. This scale is valuable for predicting operative \ntime, length of hospital stay and possible subsequent \ncomplications, making it an excellent tool for clinical and \nsurgical management22,24,41. This scale has shown high \ndiagnostic performance, with a sensitivity of 91% and a \nspecificity of 90% 22,24. According to the dPEI, one point \nis awarded for each affected compartment, resulting in a \ntotal of 10 points, as extrapelvic sites are also taken into \naccount. The severity is interpreted as follows: mild (< 2 \npoints), moderate (3-4 points), and severe (> 5 points)41.\nAlthough the sensitivity of MRI is considered to be \nbetter than that of TVUS or laparoscopy, its diagnostic \nperformance varies depending on the type of endometri-\nosis present. Accordingly, laparoscopy was found to be \nthe better method for detecting superficial endometriosis \ncompared to MRI, TVUS, or physical examination41.\nFigure 6. MRI of the abdomen and pelvis of a 36-year-old woman with right upper quadrant pain, dyspareunia, and dysmenorrhea, and cyclic \nright upper quadrant pain. A: T2-weighted image shows a subcapsular hepatic lesion with intermediate signal intensity and multiple internal \nhypointense septa (white arrow). B: T1-weighted image with fat suppression (LAVA) with a hyperintense nodule inside the lesion, showing \nan endometrioma with blood derivatives (white arrow). C: post-contrasted T1-weighted image with subtraction shows heterogeneous \nenhancement of the lesion (white arrow). The MRI findings are consistent with the diagnosis of extrapelvic extension of the endometriosis \nto the diaphragm and the perihepatic region.\nMRI: magnetic resonance imaging; LAVA: Liver Acquisition with Volume Acceleration.\nA B C\n\nJ Mex  Fed  Radiol  iMaging . 2025;4(3):142-153\n152\nCONCLUSION\nEndometriosis is a disease with a wide spectrum of \nsymptoms, signs and imaging findings, represents a \nmajor burden worldwide due to its high prevalence, \ndebilitating effects, and usually delayed diagnosis. MRI \nplays an invaluable in the non-invasive assessment of \nendometriosis, providing unmatched anatomical detail \nand sensitivity in the localization of DIE. The introduc -\ntion of standardized reports and protocols for MRI, such \nas the MRI consensus lexicon and the ENDOVALIRM \ngroup’s compartment-based approach to the assess -\nment of dPEI, strengthens understanding between \nradiologists and clinicians, and provides tremendous \nhelp in surgical and clinical planning, improving patient \noutcomes, especially when combined with clinical find -\nings and additional imaging modalities. It is important \nthat radiologists are familiar with the anatomical land -\nmarks, potential pitfalls and key imaging signs, as this \nis essential for disease compromise. This review high -\nlights the key MRI features of endometriosis and \nemphasizes the importance of close collaboration \nbetween radiologists and clinicians to optimize the out -\ncome for the patient.\nAcknowledgment\nThe authors thank Professor Ana M. Contreras-\nNavarro for her guidance in preparing and writing this \nscientific paper.\nFunding\nThe authors declare that they have not received \nfunding.\nConflicts of interest\nThe authors have no conflicts of interest to disclose.\nEthical considerations\nProtection of humans and animals.  The authors \ndeclare that no experiments involving humans or ani -\nmals were conducted for this research.\nConfidentiality, informed consent, and ethical \napproval. The study does not involve patient personal \ndata nor requires ethical approval. The SAGER guide -\nlines do not apply.\nDeclaration on the use of artificial intelligence . \nThe authors declare that no generative artificial intelli -\ngence was used in the writing of this manuscript.\nREFERENCES\n 1. Alonzo L, Cannella R, Gullo G, Piombo G, Cicero G, Lopez A, et al. \nMagnetic resonance imaging of endometriosis: the role of advanced  \ntechniques. J Clin Med. 2024;13(19):5783. doi:10.3390/jcm13195783.\n 2. Chaggar P, Tellum T, Thanatsis N, De Braud LV, Setty T, Jurkovic D. \nPrevalence of deep and ovarian endometriosis in women attending a \ngeneral gynecology clinic: prospective cohort study. Ultrasound Obstet \nGynecol. 2023;61(5):632-641. doi:10.1002/uog.26175.\nFigure 7. MRI of the pelvis of a 36-year-old woman with chronic pelvic \npain, and unilateral shooting pain extending from the buttocks to the \nposterior thigh, suggesting involvement of the sciatic nerve. Axial \nT2-weighted images show an ill-defined, spiculated, hypointense \nlesion in the right lateral pelvic wall (white arrow) with involvement \nof the sciatic nerve roots. The MRI findings are consistent with the \ndiagnosis of DIE with sciatic nerve. \nDIE: deep infiltrative endometriosis; MRI: magnetic resonance imaging.\nFigure 8. Anatomy of the female pelvic floor based on the MRI \nconsensus lexicon and the compartment-based approach of the \nENDOVALIRM group. The axial drawing shows two horizontal lines \nrepresenting the anterior, middle and posterior compartments. There \nare also two vertical lines separating the right and left lateral (purple) \nand central (green) compartments. This anatomical framework  \ncreates 9 compartments: right anterolateral, right mediolateral, right \nposterolateral,  anterocentral, mediocentral, posterocentral, left \nanterior, left medial, and left posterior with additional extrapelvic areas.\nMRI: magnetic resonance imaging.\n\nL.M. Olarte-Bermudez et al.  Endometriosis in MRI\n153\n 29. Saguintaah M, Eulliot J, Bertrand M, Prodhomme O, Béchard N, Bolivar-  \nPerrin J, et al. Canal of Nuck abnormalities in pediatric female patients. \nRadioGraphics. 2022;42(2):541-558. doi:10.1148/rg.210145.\n 30. Brainwood M, Beirne G, Fenech M. Persistence of the processus vagi -\nnalis and its related disorders. Australas J Ultrasound Med. 2020;23(1):  \n22-29. doi:10.1002/ajum.12195.\n 31. VanBuren W, Feldman M, Shenoy-Bhangle AS, Sakala MD, Young S, \nChamie LP, et al. Radiology state- of-the-art review: endometriosis ima -\nging interpretation and reporting. Radiology. 2024;312(3):e233482. doi: \n10.1148/radiol.233482.\n 32. Crispi CP, de Souza CA, Oliveira MA, Dibi RP, Cardeman L, Sato H, \net al. Endometriosis of the round ligament of the uterus. J Minim Invasi -\nve Gynecol. 2012;19(1):46-51. doi:  10.1016/j.jmig.2011.09.006.\n 33. Bourgioti C, Preza O, Panourgias E, Chatoupis K, Antoniou A, Nikolaidou \nME, et al. MR imaging of endometriosis: spectrum of disease. Diagn \nInterv Imaging. 2017;98(11):751-767. doi: 10.1016/j.diii.2017.05.009.\n 34. Guerriero S, Ajossa S, Pagliuca M, Borzacchelli A, Deiala F, Springer S, \net al. Advances in imaging for assessing pelvic endometriosis. Diagno -\nstics (Basel). 2022;12(12):2960. doi:10.3390/diagnostics12122960.\n 35. Mabrouk M, Raimondo D, Arena A, Iodice R, Altieri M, Sutherland N, \net al. Parametrial endometriosis: the occult condition that makes the hard \nharder. J Minim Invasive Gynecol. 2019;26(5):871-876. doi:10.1016/j.\njmig.2018.08.022.\n 36. Moro F, Ianieri MM, De Cicco Nardone A, Carfagna P, Mascilini F, Vizzielli \nG, et al. Comparison of clinical and ultrasound examinations in assessing \nthe parametria in patients with deep infiltrating endometriosis: a multicentre \nprospective study. Reprod Biomed Online. 2024;48(4):103733. doi:10.1016/j.\nrbmo.2023.103733.\n 37. Kinkel K, Frei KA, Balleyguier C, Chapron C. Diagnosis of endometriosis \nwith imaging: a review. Eur Radiol. 2006;16(2):285-298. doi:10.1007/\ns00330-005-2882-y.\n 38. Xiao L, White D, Kruger LF, Alwatari Y, Blackmon S, Burnett T, et al. \nThoracic endometriosis syndrome: imaging findings and the value of a \ndedicated MRI protocol. Abdom Radiol (NY). 2025. Epub ahead of print. \ndoi:10.1007/s00261-025-04835-w.\n 39. Zamurovic M, Tomic A, Djordjevic K, Simanic S, Sopta J, Rasulic L, et al. \nIsolated deep infiltrating endometriosis of the sciatic nerve: a case report \nand overview of the literature. Medicina (Kaunas). 2023;59(12):2161. \ndoi:10.3390/medicina59122161.\n 40. Hosseiny M, Khoshpouri P, Cledera T, Brun-Vergara ML, Avalos F, \nBartlett DJ. Endometriosis of the diaphragm. Radiographics. 2024;44(11): \ne240153. doi:10.1148/rg.240153.\n 41. Thomassin-Naggara I, Rousset P, Touboul C, Razakamanantsoa L,  \nManganaro L. Reasons why it is time to change imaging guidelines on \nendometriosis. Eur Radiol. 2024;34(9):6175-6181. doi:10.1007/s00330-\n024-10595-w.\n 42. Kale A, Baydili KNS, Keles E, Gundogdu E, Usta T, Oral E. Comparison \nof isolated sciatic nerve and sacral nerve root endometriosis: a review of \nthe literature. J Minim Invasive Gynecol. 2022;29(8):943-951. doi:10.1016/ \nj.jmig.2022.05.017.\n 43. Barra F, Ferrero S, Zorzi C, Evangelisti G, Perrone U, Valente I, et al. \nFrom the tip to the deep of the iceberg: parametrial involvement in en -\ndometriosis. Best Pract Res Clin Obstet Gynaecol. 2024;94:102493. \ndoi:10.1016/j.bpobgyn.2024.102493.\n 44. Ceccaroni M, Roviglione G, Farulla A, Bertoglio P, Clarizia R, Viti A, et al. \nMinimally invasive treatment of diaphragmatic endometriosis: a 15-year \nsingle referral center’s experience on 215 patients. Surg Endosc. 2021; \n35(12):6807-6817. doi:10.1007/s00464-020-08186-z.\n 45. Thomassin-Naggara I, Monroc M, Chauveau B, Fauconnier A,  \nVerpillat P, Dabi Y, et al. Multicenter external validation of the deep \npelvic endometriosis index magnetic resonance imaging score. JAMA \nNetw Open. 2023;6(5):e2311686. doi:10.1001/jamanetworkopen.2023. \n11686.\n 46. Hirata T, Koga K, Osuga Y. Extra-pelvic endometriosis: a review. Reprod \nMed Biol. 2020;19(4):323-333. doi:10.1002/rmb2.12340.\n 47. Rousset P, Rousset-Jablonski C, Alifano M, Mansuet-Lupo A, Buy JN, \nRevel MP. Thoracic endometriosis syndrome: CT and MRI features. Clin \nRadiol. 2014;69(3):323-330. doi:10.1016/j.crad.2013.10.014.\n 48. Agarwal N, Subramanian A. Endometriosis – morphology, clinical pre -\nsentations and molecular pathology. J Lab Physicians. 2010;2(1):1-9. \ndoi:10.4103/0974-2727.66699.\n 49. Chin S, Kitzing YX, Quesada J, Lo G. Endometriosis MRI: atypical cases, \npitfalls and mimics. J Med Imaging Radiat Oncol. 2024;68(4):427-433. \ndoi:10.1111/1754-9485.13670.\n 50. Lomoro P, Simonetti I, Nanni A, Cassone R, Di Pietto F, Vinci G, et al. \nExtrapelvic sciatic nerve endometriosis, the role of magnetic resonance \nimaging: case report and systematic review. J Comput Assist Tomogr. \n2019;43(6):976-980. doi:10.1097/RCT.0000000000000916.\n 3. Dinu MD, Haj Hamoud B, Amza M, Gorecki GP, Sima RM, Gica  N, et al. \nEndometriosis in menopausal women—A new age is coming? Literature \nreview. Life (Basel). 2024;14(4):485. doi: 10.3390/life14040485.\n 4. Zondervan KT, Becker CM, Koga K, Missmer SA, Taylor RN, Viganò P. \nEndometriosis. Nat Rev Dis Primers. 2018;4(1):9. doi: 10.1038/s41572-\n018-0008-5.\n 5. Chamie L. Imaging diagnosis of endometriosis. J Mex Fed Radiol Ima -\nging. 2022;1(3):138-150. doi:10.24875/JMEXFRI.M22000019.\n 6. As-Sanie S, Mackenzie SC, Morrison L, Schrepf A, Zondervan KT, Horne \nAW, et al. Endometriosis: a review. JAMA. 2025;334(1):64-78. doi: \n10.1001/jama.2025.2975.\n 7. Ryan S, McNicholas M, Eustace SJ. Anatomy for diagnostic imaging. 3rd \ned. Edinburgh: Saunders/Elsevier; 2011.\n 8. Brüel A, Christensen EI, Tranum-Jensen J, Qvortrup K, Geneser F. \nGeneser histología. 4th ed. Madrid: Panamericana; 2015.\n 9. Devine C, Gardner C, Sagebiel T, Bhosale P. Magnetic resonance ima -\nging in the diagnosis, staging, and surveillance of cervical carcinoma. \nSemin Ultrasound CT MR. 2015;36(4):361-368. doi:10.1053/j.sult.2015. \n05.004.\n 10. Prendiville W, Sankaranarayanan R. Anatomy of the uterine cervix and \nthe transformation zone. 1st ed. Lyon: International Agency for Research \non Cancer; 2017.\n 11. Bazot M, Daraï E. Diagnosis of deep endometriosis: clinical examination, \nultrasonography, magnetic resonance imaging, and other techniques. \nFertil Steril. 2017;108(6):886-894. doi: 10.1016/j.fertnstert.2017.10.026.\n 12. Rahman MS, Park Y, Hosseinirad H, Shin JH, Jeong JW. The interplay \nbetween endometriosis and obesity. Trends Endocrinol Metab. 2025. \nEpub ahead of print. doi: 10.1016/j.tem.2025.03.011.\n 13. Saha R, Pettersson HJ, Svedberg P, Olovsson M, Bergqvist A, Marions \nL, et al. Heritability of endometriosis. Fertil Steril. 2015;104(4):947-952. \ndoi: 10.1016/j.fertnstert.2015.06.035.\n 14. Seli E, Berkkanoglu M, Arici A. Pathogenesis of endometriosis. Obstet \nGynecol Clin North Am. 2003;30(1):41-61. doi: 10.1016/s0889-\n8545(02)00052-9.\n 15. Wang Y, Nicholes K, Shih IM. The origin and pathogenesis of endometri -\nosis. Annu Rev Pathol. 2020;15:71-95. doi: 10.1146/annurev-pathmechdis- \n012419-032654.\n 16. Chapron C, Chopin N, Borghese B, Foulot H, Dousset B, Vacher-Lavenu \nMC, et al. Deeply infiltrating endometriosis: pathogenetic implications of \nthe anatomical distribution. Hum Reprod. 2006;21(7):1839-1845. doi: \n10.1093/humrep/del079.\n 17. Souza D, Aráujo Jr JE, Ferreira C, Velloni F, Elias Junior J, de Barros \nN, et al. Imaging in endometriosis: current concepts. Curr Radiol Rep. \n2022;10:393. doi: 10.1007/s40134-022-00393-x.\n 18. Gui B, Valentini AL, Ninivaggi V, Marino M, Iacobucci M, Bonomo L, et al. \nDeep pelvic endometriosis: don’t forget round ligaments. Review of ana -\ntomy, clinical characteristics, and MR imaging features. Abdom Imaging. \n2014;39(3):622-632. doi: 10.1007/s00261-014-0091-3.\n 19. Allaire C, Bedaiwy MA, Yong PJ. Diagnosis and management of  \nendometriosis. CMAJ. 2023;195(10):E363-E371. doi: 10.1503/cmaj. \n220637.\n 20. Zuber M, Shoaib M, Kumari S. Magnetic resonance imaging of endome -\ntriosis: a common but often hidden, missed, and misdiagnosed entity. Pol \nJ Radiol. 2022;87:e448-e461. doi: 10.5114/pjr.2022.119032.\n 21. Fleischer K, Bachi A, Kam J, Narayanan P, Nair R, Khazali S. Bladder \nendometriosis: what do we know and what is left to find out? A narrative \nreview. Best Pract Res Clin Obstet Gynaecol. 2024;96:102536. doi: \n10.1016/j.bpobgyn.2024.102536.\n 22. Hoyos LR, Johnson S, Puscheck E. Endometriosis and imaging. Clin Ob -\nstet Gynecol. 2017;60(3):503-516. doi: 10.1097/GRF.0000000000000305.\n 23. Quesada J, Härmä K, Reid S, Rao T, Lo G, Yang N, et al. Endometriosis: \na multimodal imaging review. Eur J Radiol. 2023;158:110610. doi: \n10.1016/j.ejrad.2022.110610.\n 24. Fraser MA, Agarwal S, Chen I, Singh SS. Routine vs. expert-guided \ntransvaginal ultrasound in the diagnosis of endometriosis: a retrospective \nreview. Abdom Imaging. 2015;40(3):587-594. doi: 10.1007/s00261-014-\n0243-5.\n 25. Zheng Z, Zhang S, Zheng C, Wang R, Zhang Y, Chen P, et al. Qualita -\ntive and quantitative features of deep endometriosis in contrast-enhanced \nultrasound: an initial experience and literature review. Clin Hemorheol \nMicrocirc. 2023;85(1):73-82. doi: 10.3233/CH-231843.\n 26. Foti PV, Farina R, Palmucci S, Vizzini IAA, Libertini N, Coronella M, et al. \nEndometriosis: clinical features, MR imaging findings and pathologic \ncorrelation. Insights Imaging. 2018;9(2):149-172. doi: 10.1007/s13244-\n017-0591-0.\n 27. Sonavane SK, Kantawala KP, Menias CO. Beyond the boundaries—  \nendometriosis: typical and atypical locations. Curr Probl Diagn Radiol. \n2011;40(6):219-232. doi:10.1067/j.cpradiol.2011.01.003.\n 28. Jaramillo-Cardoso A, Shenoy-Bhangle A, Garces-Descovich A, Glickman \nJ, King L, Mortele KJ. Pelvic MRI in the diagnosis and staging of pelvic \nendometriosis: added value of structured reporting and expertise. Abdom \nRadiol (NY). 2020;45(6):1623-1636. doi: 10.1007/s00261-019-02199-6.","source_license":"CC0","license_restricted":false}