Comparison of routine pelvic US and MR imaging in patients with pathologically confirmed endometriosis

Bowel Endometriosis: Systematic Approach to Diagnosis with US and MRI

Endometriosis involving the bowel is a severe form of the disease, and the bowel is the most common site of extragenital endometriosis. Surface lesions of the bowel are considered peritoneal disease. Bowel endometriosis (BE) is defined as endometriotic tissue infiltrating the muscularis propria layer of the bowel wall. BE is estimated to affect up to 37% of patients with known deep endometriosis, highlighting its coexistence with genital endometriosis. The rectosigmoid colon is the most common segment of the bowel involved, followed by the distal small bowel. US and MRI are the most common imaging modalities used to detect BE. Depending on which bowel segment is imaged, endometriosis protocols for transvaginal US after bowel preparation with a transabdominal component and MRI and MR enterography are most commonly used. The authors provide a systematic approach to the diagnosis of BE using these imaging modalities. Imaging protocols and techniques for optimization of visualization of the bowel are discussed, the normal bowel wall anatomy with both imaging modalities is described, and the varying degrees of bowel wall involvement in endometriosis are illustrated. The imaging features of infiltration of endometriosis in the bowel muscularis propria are described in detail, along with key imaging findings to be conveyed to surgical colleagues to optimize surgical treatment and decrease complications, thereby improving overall patient outcomes. ©RSNA, 2025 Supplemental material is available for this article.

Agreement between magnetic resonance imaging and ultrasonography in deep pelvic endometriosis

OBJECTIVE

Deep pelvic endometriosis is the most common cause of chronic pelvic pain and infertility. Guidelines proposed standardized approaches for the diagnosis of deep pelvic endometriosis with ultrasonography and magnetic resonance imaging; however, knowing the reasons for discrepancy is crucial. We aimed to analyze the agreement between ultrasonography and magnetic resonance imaging for deep pelvic endometriosis findings and provide potential pitfalls and reasons for discordant findings.

METHODS

The study group consists of consecutive patients with deep pelvic endometriosis diagnosed on pelvic (n=1) or transvaginal ultrasonography (n=34) who underwent noncontrast pelvic magnetic resonance imaging. The agreement between the ultrasonography and magnetic resonance imaging was assessed using the prevalence and bias-adjusted kappa statistics. Potential pitfalls and reasons for discordant findings were presented.

RESULTS

The study group consisted of 35 patients with deep pelvic endometriosis. The mean age was 39.5±6.2 years. The most common site of involvement was the rectosigmoid colon (n=34, 97.1%), followed by endometrioma/hemorrhagic cyst (n=32, 91.4%). There was a perfect agreement for endometrioma/hemorrhagic cyst (100%), almost perfect agreement for bladder involvement (PABAK=0.886), and moderate agreement for other sites. The number of uterosacral ligament involvement was lower with ultrasonography than with magnetic resonance imaging. However, due to the impact of gas signals on magnetic resonance imaging imaging, the number and boundaries of rectosigmoid deep pelvic endometriosis were better defined with ultrasonography.

CONCLUSION

The agreement between ultrasonography and magnetic resonance imaging for deep pelvic endometriosis findings varies according to the sites of involvement. Ultrasonography and magnetic resonance imaging are not standalone diagnostic techniques but are complementary to each other. We provided potential diagnostic pitfalls.

Endometriosis imaging in the community setting: implementation of the SRU consensus recommendations on routine pelvic US

Endometriosis is a common gynecologic disorder with a significant burden of morbidity that is often subject to substantial diagnostic delay. While transvaginal ultrasound (TVUS) is the first-line imaging tool for symptoms like chronic pelvic pain and infertility, it has limitations in detecting deep endometriosis. In 2024, the Society of Radiologists in Ultrasound (SRU) issued recommendations to enhance detection by incorporating additional techniques into standard TVUS. This article outlines practical adaptations to improve diagnostic accuracy with minimal extra scan time in community practices. It covers patient selection, stakeholder involvement, training, and quality assurance while addressing implementation challenges. Community ultrasound practices play a key role in early detection, guiding patients toward appropriate care.

Best Practices: Ultrasound Versus MRI in the Assessment of Pelvic Endometriosis

Endometriosis is a common yet morbid disease. Imaging plays an important role in diagnosis and treatment planning. Both ultrasound (US) and MRI are used to detect disease. We performed a literature review to assess whether one is superior. A total of 33 studies from the 4482 identified in the initial search were found to assess the efficacy of US and/or MRI in detecting pelvic endometriosis. Most studies were performed at centers with extensive experience with endometriosis, using dedicated US and MRI protocols. A wide range of sensitivities and specificities were reported, but overall weighted means of diagnostic statistics for US and MRI were similar. The choice of dedicated US versus dedicated MRI in the evaluation of endometriosis should therefore be based on the expertise in the region. The data also showed US had better accuracy than MRI for identifying the depth of wall invasion in bowel-wall disease, whereas MRI better depicted pelvic-wall and extraperitoneal disease than US. Routine US and MRI protocols performed worse than dedicated US and MRI protocols, which may account for delays in diagnoses. Clinical and research efforts directed at improving the sensitivity of routine imaging for diagnosing deep endometriosis could improve patient access to appropriate care.

Quality Improvement Report: The Sliding Sign Initiative-Facilitating Earlier Detection of Deep Endometriosis in an Academic US Department

A delayed diagnosis of endometriosis can significantly impact a patient's quality of life. To facilitate an earlier diagnosis, we implemented a modified pelvic US protocol that included use of the dynamic sliding sign (SS) maneuver to screen at-risk populations. The aim of this initiative was to improve both SS maneuver performance and SS reporting consistency to 80% and determine the number of new endometriosis cases identified after US. A quality improvement framework based on the plan-do-study-act (PDSA) methodology was used to develop and evaluate interventions. Eligible pelvic US studies were reviewed at regular intervals to track SS maneuver performance and SS reporting, with control charts used to detect intervention-related variation. A chart review of all abnormal SS cases was also performed. The project initiation (PDSA cycle 1) included protocol development and educational sessions. Reminder posters were placed during cycle 2 and revised in cycle 3, and the eligibility criteria were revised. Cycles 4 and 5 consisted of in-person discussions, distribution of a reference guide, and creation of a dictation software macro. In terms of results, sonographers performed the SS maneuver correctly in 52.1% of eligible patients after cycle 1, increasing to 83.9% by cycle 5. In the cases in which the SS maneuver was performed by the sonographer, after PDSA cycle 1, the SS was reported by the radiologist in 69% of cases (including both correct and incorrect interpretations), and both reported and interpreted correctly in 59% of cases, reaching 79.5% by cycle 3, and plateauing thereafter. Thirty-seven patients were newly diagnosed with endometriosis after undergoing US of the SS. The objectives of our SS initiative were met, with improved SS US performance, improved SS reporting and interpretation, and a number of new endometriosis cases diagnosed. ©RSNA, 2024 Supplemental material is available for this article. See the invited commentary by Jha and VanBuren in this issue.

ACR Appropriateness Criteria® Endometriosis

Endometriosis is a common condition impacting individuals assigned female at birth. Though incompletely understood, the disorder is caused by endometrial-like tissue located outside of the endometrial cavity, associated with inflammation and fibrosis. Clinical presentation is variable, ranging from asymptomatic to severe pelvic pain and infertility. Treatment is determined by the patient's individualized goals and can include medical therapies to temporize symptoms or definitive surgical excision. Imaging is used to help diagnose endometriosis and for treatment planning. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Society of Radiologists in Ultrasound Consensus on Routine Pelvic US for Endometriosis

Endometriosis is a prevalent and potentially debilitating condition that mostly affects individuals of reproductive age, and often has a substantial diagnostic delay. US is usually the first-line imaging modality used when patients report chronic pelvic pain or have issues of infertility, both common symptoms of endometriosis. Other than the visualization of an endometrioma, sonologists frequently do not appreciate endometriosis on routine transvaginal US images. Given a substantial body of literature describing techniques to depict endometriosis at US, the Society of Radiologists in Ultrasound convened a multidisciplinary panel of experts to make recommendations aimed at improving the screening process for endometriosis. The panel was composed of experts in the imaging and management of endometriosis, including radiologists, sonographers, gynecologists, reproductive endocrinologists, and minimally invasive gynecologic surgeons. A comprehensive literature review combined with a modified Delphi technique achieved a consensus. This statement defines the targeted screening population, describes techniques for augmenting pelvic US, establishes direct and indirect observations for endometriosis at US, creates an observational grading and reporting system, and makes recommendations for additional imaging and patient management. The panel recommends transvaginal US of the posterior compartment, observation of the relative positioning of the uterus and ovaries, and the uterine sliding sign maneuver to improve the detection of endometriosis. These additional techniques can be performed in 5 minutes or less and could ultimately decrease the delay of an endometriosis diagnosis in at-risk patients.

Acute abdominal pain in women of reproductive age: keys to suggest a complication of endometriosis

Although endometriosis is a common gynecological condition in women of reproductive age, a complication of endometriosis is rarely considered as the differential diagnosis of acute abdominal pain in that context. However, acute events in women with endometriosis can represent life-threatening conditions, which require emergent treatment and often surgical management. Mass effect of endometriotic implants can give rise to obstructive complications, specifically occurring in the bowel or in the urinary tract, while inflammatory mediators released by ectopic endometrial tissue can lead to inflammation of the surrounding tissues or to superinfection of the endometriotic implants. Magnetic resonance imaging is the best imaging modality to reach the diagnosis of endometriosis, but an accurate diagnosis is possible on computed tomography, especially in the presence of stellar, mildly enhanced, infiltrative lesions in suggestive areas. The aim of this pictorial review is to provide an image-based overview of key findings for the diagnosis of acute abdominal complications of endometriosis.

Endometriosis of the skeletal muscular system (ESMS): a systematic review

BACKGROUND

Extrapelvic endometriosis occurring at skeletal muscle and joint sites is not rare and is prone to delayed diagnosis and inappropriate treatment. Herein, endometriosis of the skeletal muscular system (ESMS) is systematically reviewed to facilitate early diagnosis and treatment.

METHODS

Literature on ESMS published before March 2022 was retrieved from the Ovid Medline and Web of Science databases, and the major clinical data were extracted for descriptive analysis.

RESULTS

A total of 62 studies (78 ESMS cases) met these requirements. The ESMS included the abdominal muscles (50.7%), pelvic floor muscles (11.6%), lower limb muscles (11.6%), hip muscles (8.7%), lumbar muscles (7.2%), joints (5.8%), upper limb muscles (2.9%), and shoulder-neck muscles (1.4%). The age was 34.0 ± 7.2 years (range 17-49 years). Approximately 63.8% of patients had at least one previous pelvic surgery, and 76.8% of local symptoms were related to the menstrual cycle. The course of disease was 29.6 ± 25.4 months (range 0.5-96 months). Only 30.3% of the patients sought initial medical advice from gynecologists, while 69.7% sought initial medical advice from a nongynecological physician. Twenty-seven patients underwent fine-needle aspiration (FNA) under ultrasound or CT monitoring, and only 44.4% (12/27) were confirmed to have endometriosis by FNA tissue pathology. Approximately 47.4% (37/78) of the patients had a normal pelvic cavity appearance. Surgical resection was performed in 92.3% (72/78) of the patients, of whom 88.9% (64/72) underwent complete resection of the lesion (negative surgical margin) and 20.8% (15/72) received postoperative hormone therapy. At 16.7 months of follow-up, 83.3%, 13.8%, 2.9%, and four patients had complete response, partial response, recurrence, and permanent function impairment, respectively.

CONCLUSION

Endometriosis can occur at almost any site in the musculoskeletal system. For women of reproductive age with catamenial pain or a mass in the musculoskeletal system, endometriosis should be suspected. Fine-needle aspiration can easily lead to missed diagnoses. Surgical resection for negative margins is the main treatment, and permanent impairment of function may occur in a few patients due to delayed diagnosis. Vascular lymphatic metastasis is the most likely mechanism of pathogenesis.

Endometriosis: A multimodal imaging review

Endometriosis is a chronic inflammatory disorder characterized endometrial-like tissue present outside of the uterus, affecting approximately 10% of reproductive age women. It is associated with abdomino-pelvic pain, infertility and other non - gynecologic symptoms, making it a challenging diagnosis. Several guidelines have been developed by different international societies to diagnose and classify endometriosis, yet areas of controversy and uncertainty remains. Transvaginal ultrasound (TV-US) is the first-line imaging modality used to identify endometriosis due to its accessibility and cost-efficacy. Enhanced sonographic techniques are emerging as a dedicated technique to evaluate deep infiltrating endometriosis (DIE), depending on the expertise of the sonographer as well as the location of the lesions. MRI is an ideal complementary modality to ultrasonography for pre-operative planning as it allows for a larger field-of-view when required and it has high levels of reproducibility and tolerability. Typically, endometriotic lesions appear hypoechoic on ultrasonography. On MRI, classical features include DIE T2 hypointensity, endometrioma T2 hypointensity and T1 hyperintensity, while superficial peritoneal endometriosis (SPE) is described as a small focus of T1 hyperintensity. Imaging has become a critical tool in the diagnosis, surveillance and surgical planning of endometriosis. This literature review is based mostly on studies from the last two decades and aims to provide a detailed overview of the imaging features of endometriosis as well as the advances and usefulness of different imaging modalities for this condition.

MRI sliding sign: Using MRI to assess rectouterine mobility in pelvic endometriosis

INTRODUCTION

Surgical excision of deep infiltrating endometriosis (DIE) is complex and associated with morbidity. Diagnostic imaging plays an important role in the preoperative workup. We sought to determine the utility of single sagittal T2-weighted MRI motion sequence in the preoperative assessment of pelvic mobility in patients with endometriosis.

METHODS

An observational study at a single tertiary public referral centre in Australia. Eighty-one MRI studies from 1 May 2019 to 3 December 2019, were enrolled. Studies were included if they were performed to stage endometriosis, including a T2-weighted motion series, adequately covering a uterus, cervix and rectum. Fifty-seven studies met inclusion criteria. The reference standard was a contemporaneous transvaginal ultrasound (TVUS) reporting on pelvic organ mobility. Three subspecialist radiologists were then blindly asked to identify, on the cine loop: rectouterine immobility, superficial endometriosis (pelvic bowel adhesions), rectosigmoid Deep Infiltrating Endometriosis (DIE). Fleiss' Kappa assessed interobserver agreement. Consensus MRI sensitivity and specificity were estimated against the reference standard (TVUS).

RESULTS

Median age was 35 years (range 19-51). Forty-three cases had a contemporaneous TVUS; 14 reporting a sliding sign, 29 with fixed pelves. Interobserver agreement was 'substantial' (k = 0.79) for absent MRI sliding sign and 'almost perfect' (k = 0.90) for absence of DIE. Consensus MRI had 90% sensitivity (95% CI 73-98%) for pelvic immobility at TVUS (absent sliding sign). Interobserver agreement and consensus MRI sensitivity were higher for adhesions and immobility than normal findings.

CONCLUSION

An MRI motion sequence can identify patients with pelvic adhesions and immobility, helping determine surgical difficulty when TVUS is not diagnostic.

Encyclopedia of endometriosis: a pictorial rad-path review

Endometriosis affects approximately 10% of reproductive age women and represents a significant cause of pelvic pain and infertility. Unfortunately, the diagnosis of endometriosis is often delayed by years. Endometriosis may manifest as cystic lesions in the ovaries known as endometriomas. Superficial endometriosis is typically detected by laparoscopy along the pelvic peritoneum as these lesions tend to be difficult to detect by imaging. Deep infiltrative endometriosis may be detected by ultrasound, CT or MRI in classic locations within the pelvis, such as the posterior cul-de-sac and uterosacral ligaments. Endometriosis may also involve the thorax, gastrointestinal and urinary tracts, and locations such as the abdominal wall and abdominal organs. We present MRI and CT case examples, together with corresponding laparoscopic and histopathology images to enhance radiologists' understanding of this disease.

Percutaneous cryoablation of abdominal wall endometriosis: the Mayo Clinic approach

Abdominal wall endometriosis (AWE) is a rare form of endometriosis that often results in substantial pain and debility. The current treatment algorithm for AWE is not well established. The purpose of this review is to describe the Mayo Clinic experience with thermal ablation of symptomatic AWE as well as to review current imaging and interventional literature regarding the diagnosis and treatment of AWE.

The role of imaging as a guide to the surgical treatment of endometriosis

Minimally invasive surgery for complex endometriosis requires preoperative planning that intimately connects the gynecologic surgeon to the radiologist. Understanding the surgeon's perspective to endometriosis treatment facilitates a productive relationship that ultimately benefits the patient. We examine minimally invasive surgery for endometriosis and the key radiologic information which enable the surgeon to successfully negotiate patient counseling, preoperative planning, and an interdisciplinary approach to surgery.

Recommendations for MRI technique in the evaluation of pelvic endometriosis: consensus statement from the Society of Abdominal Radiology endometriosis disease-focused panel

Endometriosis is a common entity causing chronic pain and infertility in women. The gold standard method for diagnosis is diagnostic laparoscopy, which is invasive and costly. MRI has shown promise in its ability to diagnose endometriosis and its efficacy for preoperative planning. The Society of Abdominal Radiology established a Disease-Focused Panel (DFP) to improve patient care for patients with endometriosis. In this article, the DFP performs a literature review and uses its own experience to provide technical recommendations on optimizing MRI Pelvis for the evaluation of endometriosis.