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

Abstract 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.