A Multicenter Study Assessing the Diagnostic Accuracy of Ultrasonographic Features of the Uterosacral Ligaments in Patients With and Without Endometriosis

Study Objective: To assess the diagnostic accuracy of different ultrasonographic features of uterosacral ligaments (USLs) affected by endometriosis. Design: Multicentric, observational, prospective, diagnostic study. Setting: Two tertiary care clinics. Patients: All consecutive symptomatic patients aged between 18 and 50 years with an ultrasonographic diagnosis of endometriosis and submitted to surgery from January 2023 to July 2023. Interventions: The preoperative ultrasonographic features of the USLs were compared between those affected by USL endometriosis and those not affected, as confirmed by pathologic examination. Diagnostic accuracy metrics—including sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve (AUC)—were calculated for the following ultrasound features of the USLs: optimal anteroposterior diameter cutoff (in millimeters), echogenicity, peritoneal surface characteristics, tenderness upon targeted probe pressure, and presence of contiguous endometriotic lesions. Measurements and Main Results: Eighty-five women were enrolled. The anteroposterior diameter of the USLs affected by endometriosis was significantly higher than that of unaffected USLs (mean [±SD], 5.0 [±2.5] mm vs 3.3 [±1.6] mm; p <.001). USLs affected by endometriosis showed more frequently a hypoechoic or inhomogeneous echogenicity (p <.001), an irregular peritoneal surface (p <.001), tenderness upon target vaginal probe pressure (p <.001), and an association with rectal endometriosis lesions contiguous to the USLs (p = .004). The best USL anteroposterior diameter cutoff value to predict USL endometriosis involvement was 4.2 mm, with sensitivity, specificity, and AUC of 57.3%, 86.3%, and 0.72, respectively. The AUC was low for all the ultrasound features considered individually. The combination of each ultrasound feature with the most accurate USL anteroposterior diameter cutoff value showed a moderate accuracy in diagnosing USL endometriosis involvement. Conclusion: The combination of an anteroposterior thickness of USLs of >4.2 mm with at least 1 of the abovementioned ultrasound features suggestive of endometriosis may have a moderate diagnostic accuracy in diagnosing USL endometriosis involvement at ultrasound.