OP17.04: Accuracy of transvaginal sonography in the diagnosis of deep posterior endometriosis

To evaluate the accuracy of transvaginal sonography (TVS) in the diagnosis of deep infiltrating endometriosis of the posterior compartment (rectovaginal septum, rectosigmoid) when undertaken by sonographers of differing experience. Sonographic, surgical and histopathologic data from 246 patients operated between January 2002 and February 2005 for suspected pelvic endometriosis were retrospectively obtained. Preoperative TVS were carried out by physicians of varying experience. The presence and size of the endometriotic lesions located on the posterior compartment were compared with the surgical and histological findings. 96 patients underwent removal deep endometriotic lesions of the posterior compartment. Sensitivity, specificity, positive and negative predictive value and overall diagnostic accuracy expert operators were 69%, 95%, 93%, 73% and 83% respectively. Corresponding features for first-level operators were: 43%, 100%, 79% and 82%. In patients with positive findings at TVS, the mean diameter of the endometriotic nodule was of 5.2 ± 4.2 cm, while in cases with negative findings the average diameter was 2.7 ± 1.2 cm (p < 0.05). An intestinal resection upon removal of the nodule was unnecessary in any of the patients who recorded a false negative result. Diagnosis of deep infiltrating endometriosis is difficult when the nodules are small in size. In experienced hands TVS can reveal the presence and the location of deep endometriosis when its diameter is ≥ 1 cm. Operators with less experience in TVS have a lower sensitivity in comparison to expert physicians. To minimise operating times, rates of complication and optimize the efficacy of surgery, sonography should be carried out by adequately trained personnel with good experience.