Transvaginal ultrasonography combined with water-contrast in the rectum in the diagnosis of rectovaginal endometriosis infiltrating the bowel.

This prospective study evaluated the efficacy of transvaginal ultrasonography combined with water-contrast in the rectum (RWC-TVS) in the diagnosis of rectal infiltration in 35 women with rectovaginal endometriosis. After mechanical bowel preparation, a 6-mm catheter was inserted into the rectal lumen up to a 20-cm distance from the anus. The rectum was distended by injecting saline solution. Rectal infiltration was diagnosed when a rectovaginal hypoechoic mass penetrated into the intestinal wall thickening the muscolaris mucosa. Ultrasonographic findings were compared with surgery and histology. The sensitivity of RWC-TVS in identifying rectal infiltration reaching at least the muscular layer was 100%, the specificity was 85.7%, the positive predictive value was 91.3%, and the negative predictive value was 100%. In 4 of 5 (80.0%) nodules reaching the submucosa, the depth of infiltration was underestimated by RWC-TVS. The RWC-TVS reliably determined the largest diameter of the endometriotic nodules and was well tolerated by the patients. Transvaginal ultrasonography, magnetic resonance imaging, rectal endoscopic ultrasonography, multislice computerized tomography combined with the distension of the colon by rectal enteroclysis have previously been proposed for the diagnosis of bowel endometriosis. Combining RWC-TVS with multislice computerized tomography enteroclysis may improve our ability to diagnose rectal endometriosis before surgery.