Deep infiltrating endometriosis: Should rectal and vaginal opacification be systematically used in MR imaging?

Diagnostic MRI for deep pelvic endometriosis: towards a standardized protocol?

OBJECTIVES

To assess the diagnostic efficacy of an MRI protocol and patient preparation in detecting deep pelvic endometriosis (DPE).

MATERIAL AND METHODS

The cohort is from the ENDOVALIRM database, a multicentric national retrospective study involving women who underwent MRI followed by pelvic surgery for endometriosis (reference standard). Two senior radiologists independently analyzed MRI findings using the deep pelvic endometriosis index (dPEI) to determine lesion locations. The study evaluated the impact of bowel preparation, vaginal and rectal opacification, MRI unit type (1.5-T or 3-T), additional sequences (thin slice T2W or 3DT2W), and gadolinium injection on reader performance for diagnosing DPE locations. Fisher's exact test assessed differences in diagnostic accuracy based on patient preparation and MRI parameters.

RESULTS

The final cohort comprised 571 women with a mean age of 33.3 years (± 6.6 SD). MRI with bowel preparation outperformed MRI without bowel preparation in identifying torus/uterosacral ligament (USL) locations (p < 0.0001) and rectosigmoid nodules (p = 0.01). MRI without vaginal opacification diagnosed 94.1% (301/320) of torus/USL locations, surpassing MR with vaginal opacification, which diagnosed 85% (221/260) (p < 0.001). No significant differences related to bowel preparation or vaginal opacification were observed for other DPE locations. Rectal opacification did not affect diagnostic accuracy in the overall population, except in patients without bowel preparation, where performance improved (p = 0.04). There were no differences in diagnostic accuracy regarding MRI unit type (1.5-T/3-T), presence of additional sequences, or gadolinium injection for any endometriotic locations.

CONCLUSION

Bowel preparation prior to MRI examination is preferable to rectal or vaginal opacification for diagnosing deep endometriosis pelvic lesions.

CLINICAL RELEVANCE STATEMENT

Accurate diagnosis and staging of DPE are essential for effective treatment planning. Bowel preparation should be prioritized over rectal or vaginal opacification in MRI protocols. Optimizing MRI protocols for diagnostic performance with appropriate opacification techniques will help diagnose deep endometriosis more accurately.

KEY POINTS

Evaluating deep endometriosis in collapsible organs such as the vagina and rectum is difficult. Bowel preparation and an absence of vaginal opacification were found to be diagnostically beneficial. Bowel preparation should be prioritized over rectal or vaginal opacification in MRI protocols.

Endometriosis MR mimickers: T2-hypointense lesions

Endometriosis is a common crippling disease in women of reproductive age. Magnetic resonance imaging (MRI) is considered the cornerstone radiological technique for both the diagnosis and management of endometriosis. While its sensitivity, especially in deep infiltrating endometriosis, is superior to that of ultrasonography, many sources of false-positive results exist, leading to a lack of specificity. Hypointense lesions or pseudo-lesions on T2-weighted images include anatomical variants, fibrous connective tissues, benign and malignant tumors, feces, surgical materials, and post treatment scars which may mimic deep pelvic infiltrating endometriosis. False positives can have a major impact on patient management, from diagnosis to medical or surgical treatment. This educational review aims to help the radiologist acknowledge MRI criteria, pitfalls, and the differential diagnosis of deep pelvic infiltrating endometriosis to reduce false-positive results. Critical relevance statement MRI in deep infiltrating endometriosis has a 23% false-positive rate, leading to misdiagnosis. T2-hypointense lesions primarily result from anatomical variations, fibrous connective tissue, benign and malignant tumors, feces, surgical material, and post-treatment scars. Key points • MRI in DIE has a 23% false-positive rate, leading to potential misdiagnosis.• Anatomical variations, fibrous connective tissues, neoplasms, and surgical alterations are the main sources of T2-hypointense mimickers.• Multisequence interpretation, morphologic assessment, and precise anatomic localization are crucial to prevent overdiagnosis.• Gadolinium injection is beneficial for assessing endometriosis differential diagnosis only in specific conditions.

Patient acceptability and quality of self-administered intravaginal gel for pelvic MRI

Background:

MRI of the pelvis can be limited for infiltrating lesions or those of same signal intensity as surrounding structures. Vaginal distension using aqueous gel counters this by defining the fornices, cervix and anterior rectal wall. This increases the accuracy of diagnosis and staging of various pelvic pathology, however, there is currently neither a universally accepted protocol for using gel nor focus on patient self-administration.

Aims:

To improve patient expectations regarding pelvic MRI with intravaginal gel, as well as the service we provide should they prefer self-administration and this produces vaginal distension of radiological quality equivalent to doctor-administration.

Methods:

Illustrated information explaining the benefits of gel and the technique of self-administration was sent to patients scheduled for pelvic MRI between March 2020 and April 2021 at our study centre. This included a questionnaire to assess understanding and preference for self-administration. Vaginal distension achieved on imaging was analysed using TeraRecon and compared between self and doctor-administered cases.

Results:

38 of 45 patients opted for self-administration of gel. Those who identified as White British were more likely to self-administer. There was comparable quality of vaginal distension between self and doctor administered cases, with no significant difference between orthogonal measurements and retained gel volume.

Conclusion:

Self-administration of intravaginal gel for pelvic MRI is acceptable to patients and frees a doctor of this duty. It is a well tolerated technique which produces high quality vaginal distention on imaging. We recommend wider use of intravaginal and even rectal gel in the investigation of complex endometriosis and pelvic tumours.

Value of 3D MRI and Vaginal Opacification for the Diagnosis of Vaginal Endometriosis

Objective: The aim of the study was to evaluate three-dimensional (3D) T2 MRI before and after vaginal opacification (VO) by gel (3DT2VO) and the additional value of 3DT1 with fat-suppression (3DT1FS) MRI in the diagnosis of vaginal endometriosis.

Methods: In this study conducted from 2010 to 2013, 51 patients scheduled for surgical treatment of endometriosis underwent MRI 1 day before surgery. Three readers (novice, intermediate, expert) were asked to retrospectively diagnose vaginal endometriosis independently and blindly using four different readings (i.e., 3DT2, 3DT2VO, 3DT2 with 3DT1FS, 3DT2VO with 3DT1FS). Vaginal endometriosis diagnosis was positive on observation of a thickening of vaginal walls on 3DT2 with or without high-signal-intensity spots on 3DT2 and/or 3DT1FS. The reference standard was surgery and histology. Descriptive analysis, Chi-square test, and ROC curves were used for statistical analysis.

Results: For all readers, the combination of 3DT2 and 3DT1FS significantly improved the diagnosis of vaginal endometriosis compared with 3DT2 (p = 0.002, p = 0.02, and p = 0.003). 3DT2VO significantly improved diagnosis for the intermediate reader (p = 0.01). High-signal-intensity spots on 3DT1FS had a sensitivity of 50–63.6%, specificity of 86.2–96.6%, and high positive likelihood ratios (14.5-Inf).

Conclusion: 3DT2 in association with 3DT1FS appears to be the best 3D MRI protocol for the diagnosis of vaginal endometriosis, whatever the level of experience of readers. The additional value of 3DT2VO is variable among the readers.

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.

Assessment of the Effectiveness of the Vaginal Contrast Media in Magnetic Resonance Imaging for Detection of Pelvic Pathologies: A Meta-analysis

OBJECTIVE

Magnetic resonance imaging (MRI) is an excellent modality for pelvic imaging. The anatomy of uterine cavity and vagina is optimally evaluated when the walls, which may spontaneously be collapsed, are distended. Distension of these cavities during pelvic MRI for evaluation of gynecologic diseases has been conducted with vagina, filled with ultrasound gel or saline solution. In this meta-analysis, we aim to assess the effectiveness of vaginal contrast media in MRI for improving the detection of pelvic pathologies.

METHODS

The PubMed, MEDLINE, EMBASE, Web of Science, Google Scholar, Science Citation Index, and Cochrane Library databases were systematically searched through March 2019 for studies of the accuracy of MRI using vaginal contrast media in the diagnosis and staging of pelvic pathologies. Four eligible studies of a total of 120 patients were included in the meta-analysis. The sensitivity rates and relative risk for MRI, before and after vaginal contrast medium administration, were pooled, and their 95% confidence intervals (CIs) were determined.

RESULTS

The pooled sensitivity rate for MRI before administering intravaginal contrast medium in detecting pelvic pathologies was 63% (95% CI, 54%-72%), and that after was 89% (95% CI, 83%-93%). The interstudy heterogeneity rate (assessed using the I statistic) was relatively low: 13% (P = 0.33) and 0% (P = 0.45) before and after vaginal contrast medium use, respectively. The average relative risk was 1.54 (SD, 0.22; 95% CI, 1.18-1.89; median, 1.50; range, 1.34-1.80). This demonstrated that, on average, the sensitivity rate for MRI in detecting pelvic disorders increased by 54% after the use of a vaginal contrast medium.

CONCLUSIONS

Use of vaginal contrast media improved the diagnostic ability of MRI in identifying pelvic pathologies.

Magnetic Resonance Imaging Compared with Rectal Endoscopic Sonography for the Prediction of Infiltration Depth in Colorectal Endometriosis

STUDY OBJECTIVE

To compare the accuracies of magnetic resonance imaging (MRI) and rectal endoscopic sonography (RES) in the prediction of the infiltration depth of colorectal endometriosis.

DESIGN

A retrospective cohort study (Canadian Task Force classification II-2).

SETTING

A university teaching hospital.

PATIENTS

Forty patients with symptomatic deep infiltrating endometriosis (DIE) of the rectum who underwent colorectal resection were included.

INTERVENTIONS

All patients underwent abdominopelvic MRI and RES preoperatively to assess the infiltration depth of colorectal endometriosis, and segmental resection of the rectosigmoid by laparoscopy was performed if RES showed bowel invasion. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive and negative likelihood ratios (LRs), and intermethod agreement were calculated for DIE muscularis and submucosal/mucosal infiltration confirmed by histopathological analysis.

MEASUREMENTS AND MAIN RESULTS

For MRI detection of DIE muscularis infiltration, the sensitivity, specificity, PPV, NPV, and negative LR were 68%, 100%, 100%, 20%, and 0.32, respectively. For the MRI detection of DIE submucosal/mucosal involvement, the sensitivity, specificity, PPV, NPV, and positive and negative LRs were 47%, 81%, 69%, 63%, 2.49, and 0.65, respectively. The PPV of RES detection of DIE muscularis infiltration was 93%. For the RES detection of DIE submucosal/mucosal layers, the sensitivity, specificity, PPV, NPV, and positive and negative LRs were 79%, 48%, 58%, 71%, 1.51, and 0.44, respectively.

CONCLUSION

In the current study, MRI is valuable for detecting endometriosis of the rectum but is less accurate in detecting submucosal/mucosal involvement than RES. Magnetic resonance imaging was not successful for preoperative determination of segmental resection versus a more conservative approach. When bowel involvement is detected by MRI, RES is not essential. When symptoms suggest DIE in patients without intestinal lesions detected by MRI, RES is necessary to exclude bowel invasion.