VP62.04: A prospective study comparing rectal water‐contrast transvaginal ultrasonography with sonovaginography for the diagnosis of deep posterior endometriosis

Preoperative assessment of deep posterior endometriosis (DE) nodules is necessary to inform patients about the possible treatments and to provide informed consent in case of surgery. This study aims to investigate the accuracy of rectal water-contrast transvaginal ultrasonography (RWC-TVS) and sonovaginography (SVG) in women with suspicion of posterior DE. This prospective comparative study enrolled women with clinical suspicion of posterior DE. Criteria of exclusion were a previous diagnosis of posterior DE by magnetic resonance, computed tomography, or laparoscopy. All patients underwent RWC-TVS and SVG, independently performed by two ultrasonographers blinded to the results of the other technique. Patients underwent laparoscopic surgery within the following 6 months; findings of imaging were compared with surgical and histological results. In 215 out of 254 (84.6%) patients enrolled, posterior DE was surgically confirmed in rectovaginal septum (n = 83), recto sigmoid (n = 49), uterosacral ligaments (n = 137), and vagina (n = 13). RWC-TVS and SVG demonstrated similar sensitivity (SE; 93.0% vs 89.8%; p = 0.17) and specificity (SP; 87.2% vs 82.1%; p = 0.69) in diagnosing posterior DE. Specifically, both exams had similar accuracy in detecting nodules of uterosacral ligaments (p = 0.44), vagina (p = 0.63) and rectovaginal septum (p = 0.51). The intestinal nodules were located on sigmoid colon in 22.4%, on rectosigmoid junction in 16.3%, on upper rectum in 28.6%, and on lower rectum in 32.7% of patients. RWC-TVS had higher SE (91.8% vs 77.6%; p = 0.04) and similar SP (99.5% vs 98.5%; p = 0.50) in diagnosing rectosigmoid endometriosis and estimated better infiltration of intestinal mucosa/submucosa (p = 0.13), and distance between nodule and anal verge (p = 0.08); only RWC-TVS allowed the estimation of bowel lumen stenosis. RWC-TVS and SVG have similar accuracy in the diagnosis of DE. RWC-TVS has a higher performance in assessing the characteristics of rectosigmoid endometriosis.