Combined Transvaginal/Transabdominal Pelvic Ultrasonography Accurately Predicts the 3 Dimensions of Deep Infiltrating Bowel Endometriosis Measured after Surgery: A Prospective Study in a Specialized Center

Study objective: To assess the sensitivity and accuracy of combined transvaginal/ transabdominal ultrasonography (TV/TA US) for evaluation of deep infiltrating bowel endometriosis nodules measured after surgery.

Design: Prospective study (Canadian Task Force classification II.1).

Setting: A center for advanced endoscopic gynecologic surgery.

Patients: All women undergoing laparoscopic surgery and scheduled for segmental resection for clinically suspected bowel endometriosis between January 2014 and December 2016.

Interventions: In all women with clinically suspected bowel endometriosis, a US scan was performed before surgery to detect and measure the 3 diameters of bowel endometriotic lesions: longitudinal, anteroposterior, and transverse. These diameters were compared with those obtained by direct measurement on a fresh specimen. The sensitivity and specificity values of US evaluation were calculated, with 95% confidence intervals.

Measurements and main results: The sensitivity and specificity of TV/TA US in the 328 patients of this study were 100% when rectal endometriotic lesions were investigated. The specificity was 100%, whereas the sensitivity decreased to 91.4% when sigmoid lesions were investigated. Bowel muscularis infiltration was histologically confirmed in all cases in which endometriotic lesions were detected by US (284 of 284; 100%). All missed sigmoid lesions (12 of 296) were located >25 cm from the anal verge. The mean diameters of endometriotic nodules calculated by US evaluation and by direct measurement on the fresh specimen were 43.19 × 19.87 × 10.79 mm and 42.76 × 19.64 × 10.62 mm, respectively, with no statistically significant differences between the 2 methods.

Conclusion: We believe that US can be considered an accurate diagnostic technique for the evaluation of deep infiltrating bowel endometriosis when performed by a dedicated experienced sonographer in a specialized center.