Original article
Genitourinary imaging
Bladder endometriosis: Preoperative MRI analysis with assessment of extension to ureteral orifices

https://doi.org/10.1016/j.diii.2020.11.011Get rights and content
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Highlights

  • MRI enables to accurately locate endometriosis implants within the bladder wall.

  • Low bladder volume impacts distance estimation between endometriosis implants and ureteral orifice.

  • A bladder volume > 150 mL seems to allow a more accurate MRI evaluation of bladder endometriosis.

  • Optimized bladder repletion is critical for the analysis of bladder endometriosis.

Abstract

Purpose

The purpose of this study was to retrospectively evaluate the performance of magnetic resonance imaging (MRI) in locating endometriosis implants within the bladder wall with assessment of ureteral orifice extension using surgical findings as standard of reference.

Materials and methods

MRI examinations of 39 consecutive women (mean age: 31.2 ± 5.5 [SD] years; age range: 22–42 years) operated in 3 university hospitals for bladder endometriosis over a 6-year period were reviewed by 2 independent readers. Interobserver agreement was assessed using Kappa tests. Results of consensus reading were used to calculate sensitivity, specificity and accuracy of MRI for the diagnosis, location and extent of endometriosis implants using surgical findings as the standard of reference.

Results

Mean bladder repletion volume was 134 ± 110 [SD] mL (range: 21–479 mL). The mean largest endometriosis implant diameter was 30 ± 7 [SD] mm (range: 19–41 mm). On MR images, 34/39 (87%) endometriosis implants were present in the two anterior thirds of the dome (k = 0.45), 31/39 (79%) extended or were present in the posterior third pouch (k = 0.92) and 25/39 (64%) extended into the bladder base (k = 0.84) with sensitivities of 100% (31/31; 95% confidence interval [CI]: 89–100%), 100% (30/30; 95% CI: 88–100%) and 90% (19/21; 95% CI: 69–98%), respectively, specificities of 83% (5/6, 95% CI: 36–100), 88% (7/8, 95% CI: 47–100%), 87% (13/15; 95% CI: 52–96), respectively and accuracies of 97% (36/37, 95% CI: 86–100%), 97% (37/38; 95% CI: 86–100%), and 89% (32/36; 95% CI: 74–97%), respectively. In 9 (9/25; 36%) patients with bladder base involvement, a zero distance was reported between endometriosis implants and ureteral orifices, all but one presenting with low-to-moderate bladder volumes. In the two patients who needed ureteral resection-reimplantation, ureteral dilation was associated with a zero distance. External adenomyosis was reported in 26/39 (66%) patients (k = 0.94).

Conclusion

A dedicated preoperative MRI work-up for bladder endometriosis helps accurately depict and locate endometriosis implants. Adequate bladder filling is needed to improve appropriate estimate of the distance between endometriosis implants and ureteral orifices to better predict requirement of ureteral resection-reimplantation.

Keywords

Adenomyosis
Cystectomy
Endometriosis
Magnetic resonance imaging (MRI)
Urinary bladder diseases

Abbreviations

CI
Confidence Interval
DIE
Deep Infiltrating Endometriosis
MS
Millisecond
mL
Milliliter
MRI
Magnetic Resonance Imaging
SD
Stantard Deviation
URR
Ureteral Resection-Reimplantation
TR/TE
Time to Repetition/Time to Echo
TVU
Transvaginal Ultrasound

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