OC20.01: Preoperative mapping of deep infiltrating endometriosis in the posterior compartment using transvaginal strain elastography and IDEA classification

To perform an investigation the use of strain elastography in order to determine the effectiveness of this method for the evaluation of deep infiltrating endometriosis (DIE) nodules in the posterior compartment. We used the IDEA (International Deep Endometriosis Analysis group) sonography overview protocol for patients with suspected endometriosis. Over a period of 19 months 325 consecutive patients were examined. The degree of strain was visualised using the colour codes placed on the B-mode image. In the posterior compartment the suspected endometriotic nodules and their adjacent tissues covered with peritoneum, the tissue displacement rates were computed. Differences in the tissue deformity were then compared to adjacent, nonaffected organs and peritoneal sections. Laparoscopic surgery and histological examination were performed for all patients. In the rectovaginal space using strain elastography, deep infiltrating nodules presented a typical blue (hard) appearance with a clearly defined outer border. The method showed 98% rectal and 92% of the rectosigmoideal nodules. Sacrouterin ligament nodules were detected in 96%. Strain ratios in the nodules varied from 0.051% to 0.212%. During the detection of endometriotic nodules, a difference in the tissue deformity values of more than twice between the controll and affected areas was considered significant. In 61% of DIE nodules the central area of the nodule was softer (green) then the marginal zone. Elastography of the rectovaginal space may be an objective method for assessment of deep infiltrating endometriosis in the posterior compartment. Using the data earned by the elastography about the severity of the disease can help to guide the surgeon preparing for surgical intervention.