RCOG World Congress 2025

Ultrasound Diagnosis of Superficial Peritoneal & Uterosacral Ligament Endometriosis (SPULE)
Z LAING-AIKEN1, J LUDLOW1,2
1. Women and Babies Department, Royal Prince Alfred Hospital, Sydney, Australia
2. Ultrasound Care, Sydney, Australia

BACKGROUND

•Transvaginal ultrasound (TVS) is a reliable tool for the diagnosis of deep infiltrating endometriosis, including Pouch of Douglas (POD) obliteration and rectal nodules.

•Recent publications have demonstrated techniques to improve the diagnosis of superficial peritoneal (SP) and uterosacral ligament (USL) endometriosis (SPULE).

•The objective of this study was to determine whether TVS is an accurate, reliable tool for the diagnosis of SPULE.

•In studies published to date TVS diagnosis of SPULE, the same practitioner(s) have performed both the TVS and the laparoscopic surgery, introducing significant bias and reducing generalisability.

DESIGN

•Retrospective observational cohort study at a tertiary hospital network in Sydney, Australia, between 1/1/2019 and 30/12/2023

METHODS

•Participants underwent TVS and diagnostic laparoscopy for investigation and management of endometriosis by multiple sonologists and surgeons.

•TVS assessed potential SPULE features, including USL thickening, hypoechoic nodules and increased echogenic material in the POD, pelvic side wall (PSW) and pararectal region.

•The findings were compared with laparoscopy

•Sensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) were calculated

RESULTS

•Median age: 33 years.

•Most common referral reasons: dysmenorrhoea (n=61) and dyspareunia (n=42; 31%).

•TVS findings: 56% deep endometriosis (DE), 26% superficial (SE), 18% negative for DE/SE.

•Laparoscopy: 89% had endometriosis; 81% peritoneal, 79% USL involvement.

•The presence of any TVS SPULE feature correctly diagnosed endometriosis with sensitivity of 93%, specificity of 53%, PPV 94% and NPV 32%

•Limitations: Heterogeneous reporting of ultrasound and laparoscopy findings.

CONCLUSION

•TVS can support non-invasive diagnosis of SPULE when UL thickening, hypoechoic nodules, or echogenic material are visualised.

•Due to the high prevalence of endometriosis in this cohort, findings may not be generalisable to all gynaecological TVS settings.

•A low NPV suggests negative scans do not reliably exclude SPULE, while low specificity indicates some sonographic features may lack diagnostic precision.

•Future directions include evaluation of false positive and false negative cases, with the aim of refining diagnostic criteria for SPULE and contributing to standardised reporting protocols.

REFERENCES

AJUM 2019;22:157-164; ANZJOG 2019;22:157-164; UOG 2020;55:137-139; UOG 2024;63:263-270

RCOG World Congress 2025

Ultrasound Diagnosis of Superficial Peritoneal and Uterosacral Ligament Endometriosis (SPULE)

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