Lesion-to-anal-verge distance in rectosigmoid endometriosis on transvaginal sonography vs magnetic resonance imaging: prospective study

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.

Ultrasound Diagnosis of Bowel Endometriosis

BACKGROUND

Bowel endometriosis is one of the more severe manifestations of deep endometriosis; it may cause pain and intestinal symptoms. The noninvasive diagnosis of bowel endometriosis is of crucial importance in planning the management of patients affected by this condition.

OBJECTIVES

This review aims to describe how transvaginal ultrasonography (TVS) is performed in patients with suspicion of rectosigmoid endometriosis, the diagnostic performance, and the strengths and limitations of this technique.

METHODS

To identify relevant literature, a literature search was performed across the PubMed and Google Scholar databases up to July 2024.

OUTCOME

Numerous meta-analyses have demonstrated that TVS has high diagnostic accuracy in diagnosing rectosigmoid endometriosis. Rectosigmoid nodules can present with different morphological characteristics, but they are typically described as irregular, hypoechoic nodules located in the anterior wall of the rectosigmoid colon. The presence of "soft markers," such as a negative sliding sign and kissing ovaries, can further reinforce the diagnosis of this condition. Posterolateral parametrial involvement often coexists with large rectal nodules. Introducing water contrast into the rectosigmoid does not improve the performance of TVS in diagnosing rectosigmoid endometriosis.

CONCLUSIONS AND OUTLOOK

TVS should be the first-line investigation in women suspected of having rectosigmoid endometriosis. The widespread use of TVS for the diagnosis of intestinal endometriosis can reduce diagnostic delays and facilitate the treatment of patients affected by this condition.

Gastrointestinal function and pain outcomes following segmental resection or discoid resection for low rectal endometriosis

INTRODUCTION

This study aims to examine the effect of full thickness discoid resection (FTDR) and modified, limited nerve-vessel sparing segmental bowel resection (NVSSR) in symptomatic patients with low rectal deep endometriosis (DE) within 7 cm from the anal verge.  Presurgical and postsurgical evaluation of gastrointestinal (GI) function reflected by low anterior resection syndrome (LARS) and gastrointestinal function-related quality of life index (GIQLI) scores, complication rates, pain scores/visual analog scale (VAS) and endometriosis health profile (EHP-30) was performed.

METHODS

In this prospective multicenter cohort study, 63 premenopausal patients with symptomatic low (within 7 cm from the anal verge) colorectal endometriosis, undergoing low modified limited nerve vessel sparing rectal segmental bowel resection (NVSSR) and full thickness discoid resection (FTDR) were evaluated. Presurgery and postsurgery lower anterior resection syndrome (LARS) scores, gastrointestinal function-related quality of life index (GIQLI), pain symptoms, endometriosis health profile (EHP-30) parameters compared between two groups.

RESULTS

Out of 63 women, 49 (77.8%) underwent NVSSR while 14 (22.2%) underwent FTDR. LARS-like symptoms were observed presurgically in 24/63 (38.1%) patients. Postsurgical LARS was observed in 14/63 (22.2%) of the patients (10/49, 20.4% in NVSSR vs. 4/14, 28.5% in the FTDR group). The LARS-like symptoms significantly decreased following surgery in the FTDR group (p = 0.049) and showed a trend for decrease in the NVSSR group (p = 0.077). Postsurgical de novo LARS was only observed in 5/63 (8%) of the patients (NVSSR 4/49, 8.1%, FTDR 1/14, 7.1%). Postsurgical GIQLI scores improved in both groups (p < 0.001) with comparable changes in the NVSSR and FTDR cohorts (p = 0.490). Postoperative grade III complication rates between NVSSR and FTDR did not vary significantly (6/49, 12.2% vs. 3/14, 21.4% p = 0.26). Pain/VAS scores and EHP-30 scores significantly decreased after a mean follow-up of 29.6 ± 11 months and 30.6 ± 11 months in the NVSSR and FTDR groups, respectively (EHP-30; p < 0.001; dysmenorrhea, dyspareunia, dyschezia all p < 0.05 for both cohorts).

DISCUSSION

When comparing low colorectal surgery by either NVSSR or FTDR in a high-risk group for surgical complications, both techniques confer improvement of GI function reflected by LARS and GIQLI with non-significant differences in major complication rates, reduced pain and EHP-30 scores.

Lesion size and location in deep infiltrating bowel endometriosis: Correlation with gastrointestinal dysfunction and pain

INTRODUCTION

Presence of deep infiltrating bowel endometriosis (DE) is associated with occurrence of dyschezia and gastrointestinal symptoms. The degree of the disease, the lesion length, and the location, that is, lesion-to-anal-verge distance (LAVD) of DE, as well as the severity of the symptoms appear to be correlated. Nevertheless, it is not yet known to what extent the size and LAVD of bowel DE influence the severity of gastrointestinal symptoms. The present study aims to evaluate a possible correlation of lesion location (LAVD) and size (according to the #Enzian classification) with preoperative symptoms.

MATERIAL AND METHODS

In this prospective study, premenopausal patients with histologically confirmed DE undergoing modified limited nerve-vessel sparing rectal segmental bowel resection or full-thickness discoid resection were evaluated. Extent of endometriosis was defined according to the #Enzian classification during surgery. The primary outcome measure was the correlation between lesion size and location with the GI function impairment reflected by presurgical lower anterior resection syndrome (LARS) scores; the secondary outcome was differences in presurgical numeric rating scale pain scores of dyschezia, dyspareunia, and dysmenorrhea as well as the impact of concomitant DE of other locations on symptom intensity.

RESULTS

Of 162 consecutive patients, 151 were included in the final analysis. No significant correlation was observed between lesion size (#Enzian compartments C1/C2/C3) or LAVD and GI dysfunction reflected by LARS-like symptoms (p = 0.314 and p = 0.185, respectively) or pain symptoms (dyschezia, p = 0.440; dyspareunia, p = 0.136; and dysmenorrhea p = 0.221). Furthermore, no significant correlation was observed between lesion size and GI dysfunction when merging two severity grades (#Enzian compartments C1 plus C2 vs. C3; p = 0.611). In addition, LAVD did not affect the degree of dyschezia (p = 0.892), dyspareunia (p = 0.395), or dysmenorrhea (p = 0.705). Finally, the presence of concomitant DE lesions infiltrating the vagina/rectovaginal space (#Enzian compartment A) and/or sacrouterine ligaments/parametrium (#Enzian compartment B) did not alter the severity of preoperative dyschezia (p = 0.493) or dysmenorrhea (p = 0.128) but showed a trend toward affecting gastrointestinal function (p = 0.078) and was significantly associated with dyspareunia (p = 0.035).

CONCLUSIONS

In present study, we could not find a correlation between colorectal DE lesion size and location (LAVD) and gastrointestinal function impairment or intensity of dyschezia and dysmenorrhea. Additional involvement of vagina/rectovaginal space (#Enzian compartment A) and/or sacrouterine ligaments/parametrium (#Enzian compartment B) exerts a significant impact on the degree of dyspareunia in women with colorectal DE.

Surgical treatment of colorectal endometriosis: an updated review

PURPOSE OF REVIEW

This review aims to summarize recent literature on the surgical treatment of colorectal endometriosis.

RECENT FINDINGS

The last decade has seen a surge in the number of studies on bowel endometriosis, with a focus on preoperative evaluation, perioperative management, surgical approach, and surgical outcomes. Many of these studies have originated from large-volume referral centers with varying surgical approaches and philosophies. Colorectal surgery for endometriosis seems to have a positive impact on patient symptoms, quality of life, and fertility. However, these benefits must be weighed against a significant risk of postoperative complications and the potential for long-term bowel or bladder dysfunction, especially for more radical procedures involving the lower rectum. Importantly, most studies regarding surgical technique and outcomes have been limited by their observational design.

SUMMARY

The surgical management of bowel endometriosis is complex and should be approached by a multidisciplinary team. Methodical preoperative evaluation, including appropriate imaging, is vital for surgical planning and patient counseling. The decision to perform a more conservative or radical excision is nuanced and remains an area of controversy. High quality studies in the form of multicenter randomized controlled trials are needed before clear recommendations can be made.

Diagnosis of superficial endometriosis on transvaginal ultrasound by visualization of peritoneum of pouch of Douglas

OBJECTIVE

Around 80% of women with endometriosis have superficial endometriosis (SE) rather than ovarian or deep endometriosis (DE). However, to date, advances in non-invasive, imaging-based diagnosis have been limited to DE or ovarian disease. The objective of this study was to determine whether we can detect SE on transvaginal ultrasound scan (TVS) by assessing the peritoneum of the pouch of Douglas (POD).

METHODS

This was a retrospective diagnostic test study following a change in practice to include POD peritoneum assessment for SE during TVS at a tertiary London hospital. Eligible patients underwent TVS by a single clinician trained in endometriosis scanning and a subsequent surgical procedure (laparoscopy) between April 2018 and September 2021. Participants formed a consecutive series. The TVS findings were compared with those of laparoscopy as the gold standard. Comparison of TVS findings with intraoperative findings was performed by calculating the diagnostic test performance measures (sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and positive and negative likelihood ratios).

RESULTS

The study included a total of 100 patients. We found that 43/100 (43.0%) patients had no endometriosis, 33/100 (33.0%) had SE and 24/100 (24.0%) had DE on laparoscopy. SE was correctly detected on TVS in 17/33 patients, with a sensitivity of 51.5% (95% CI, 33.5-69.2%), specificity of 94.0% (95% CI, 85.4-98.4%), PPV of 81.0% (95% CI, 60.8-92.1%) and NPV of 79.7% (95% CI, 73.4-84.9%). DE was correctly diagnosed in 20/24 cases, including all ovarian cases, with a sensitivity of 83.3% (95% CI, 62.3-95.3%), specificity of 97.4% (95% CI, 90.8-99.7%), PPV of 90.9% (95% CI, 71.6-97.5%) and NPV of 94.9% (95% CI, 88.3-97.8%). The detection of SE on TVS was most accurate in the POD (sensitivity, 50.0%; specificity, 96.4%; PPV, 76.9%; NPV, 88.9%).

CONCLUSIONS

This study shows that the detection of SE in the POD is possible using routine TVS. While negative TVS does not reliably confirm the absence of disease or replace diagnostic laparoscopy, positive TVS facilitates non-invasive diagnosis for a much larger group of women than was previously possible. This should help to reduce the time from the onset of symptoms to diagnosis and enable initiation of medical treatment without the risk, cost and delay associated with a surgical diagnosis. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Intra- and interobserver reproducibility of transvaginal ultrasound for the detection and measurement of endometriotic lesions of the bowel

INTRODUCTION

The number and invasion depth of endometriotic bowel lesions, total length of bowel affected by endometriosis, lesion-to-anal verge distance, and extent of pouch of Douglas obliteration are important factors in preoperatively determining risk and complexity of endometriosis surgery. The intra- and interobserver reproducibility of transvaginal ultrasound in the evaluation of many of these parameters has not yet been investigated. Our study aimed to assess the intra- and interobserver reproducibility of transvaginal ultrasound between an experienced and less experienced examiner for all of these parameters.

MATERIAL AND METHODS

This prospective observational cross-sectional study was conducted between July 2019 and November 2020. Fifty consecutive premenopausal women who underwent transvaginal ultrasound examination in our clinic for the first time, were examined by the same two operators during the same attendance. Outcomes of interest were the inter-rater reproducibility of transvaginal ultrasound for detecting the presence, number, depth and size of bowel endometriotic nodules, lesion-to-anal-verge distance, total length of bowel affected, and pouch of Douglas obliteration. The intraobserver reproducibility was assessed for the continuous parameters. Cohen's kappa (κ) statistic, Cohen's weighted kappa (κ), proportions of agreement, intraclass correlation coefficient (ICC) and Bland-Altman limits of agreement were used to assess the reproducibility of the parameters.

RESULTS

The inter-rater agreement and reliability were very good for identifying bowel endometriosis, the number and invasion depth of bowel nodules, determining whether the maximum nodule length was <3 cm, and lesion-to-anal-verge distance <8 cm (proportion of agreement 0.92, 0.94, 0.97, 0.94, 0.96; κ 0.92, 0.91, 0.92, 0.82, 0.89). The inter-rater agreement and reliability were good for assessing pouch of Douglas obliteration (proportion of agreement 0.86, κ 0.80). The intra-rater reliability for the mean nodule diameter (ICC 0.93 and 0.97) and total length of bowel affected (ICC 0.94 and 0.91) were excellent for operators A and B, respectively. The inter-rater reliability for the mean nodule diameter was good (ICC 0.80), and moderate for the total length of bowel affected (ICC 0.70). The Bland-Altman limits of agreement demonstrated clinically acceptable ranges for these two parameters.

CONCLUSIONS

This study demonstrated a high intra- and inter-rater reproducibility of transvaginal ultrasound in the diagnosis of bowel endometriosis and measurement of its various components.