ULTRASOUND for endometriosis, a condition in which tissue resembling the lining of the uterus develops outside the uterine cavity, performed similarly to magnetic resonance imaging (MRI) for the preoperative detection of endometriotic lesions and adhesions, according to a prospective observational study of 463 women.
The study assessed imaging against laparoscopic findings in women undergoing surgery for suspected endometriosis at a tertiary referral centre between April 2021 and May 2024. All participants underwent transvaginal and transabdominal ultrasound using the International Deep Endometriosis Analysis (IDEA) protocol, alongside MRI.
Ultrasound demonstrated high sensitivity and specificity across the #Enzian compartments assessed. For ovarian endometriosis, sensitivity reached 97.52% on the left and 97.22% on the right, with specificity of 96.77% and 97.73%, respectively.
For deep endometriosis involving the rectosigmoid bowel, ultrasound had 95.79% sensitivity and 95.60% specificity. MRI showed corresponding values of 94.21% and 94.14%.
The main statistically significant difference was seen in compartment T, which covers adhesions involving the tubo-ovarian unit. Ultrasound had higher specificity than MRI on both the left side (96.63% vs 92.70%; p=0.0336) and right side (94.79% vs 89.86%; p=0.0153).
No other sensitivity or specificity comparison between the modalities reached statistical significance.
Ultrasound showed higher exact concordance with laparoscopic severity grading than MRI for adnexal lesions and adhesions. Concordance was 96.3% versus 94.8% for left ovarian disease and 97.2% versus 94.6% for right ovarian disease.
For tubo-ovarian adhesions, exact concordance was 93.9% versus 89.0% on the left and 92.6% versus 86.7% on the right. For rectosigmoid deep endometriosis, ultrasound had a 3.1 percentage-point advantage in exact concordance with laparoscopy, at 94.0% versus 90.9%.
The findings suggested that ultrasound performed according to the IDEA protocol could provide diagnostic performance comparable to MRI across relevant #Enzian compartments. Its higher specificity for compartment T and closer agreement with surgical severity grading in several areas could be relevant to preoperative assessment.
Reference
Pete B et al. Head-to-head prospective comparison of diagnostic accuracy of preoperative ultrasonography and MRI in patients undergoing surgery for deep endometriosis using #Enzian classification. Ultrasound Obstet Gynecol. 2026;DOI:10.1002/uog.70298.
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