EP26.02: Ultrasound accuracy of transvaginal ultrasound compared with magnetic resonance image in deep infiltrating endometriosis

The diagnosis accuracy of deep infiltrating endometriosis (DIE) for magnetic resonance (MRI) and transvaginal scan (TVS) is not well stabilised and varies widely. The aim of this study was to assess the accuracy of TVS and MRI by comparing with surgical findings in our centre. Prospective observational study carried out between years 2009 and 2014, during which time 393 consecutive patients with clinically suspected DIE were evaluated. Among them, 48 patients who had surgery, TVS and MRI at our centre were the objective of this issue. Our ultrasound (US) protocol includes a bowel preparation with a rectal enema 12h before scan. US examination was carried out with transabdominal scan (panoramic view of the pelvis organs and abdomen, with special attention to renal pelvis and ureters) and TVS. The vaginal probe was moved gently to evaluate the uterus and adnexa, vesicovaginal space, vesical wall, uterosacral ligaments (USL), retrocervical area and pouch of Douglas (RCPD), recto-sigmoid bowel (RS), lateral compartment and rectovaginal septum. The displacement of the structures over each other (sliding sign) and tender pain under pressure were also evaluated. US diagnosis of deep infiltrating endometriosis (DIE) was made if at least one these structures showed an abnormal hypoechoic linear or nodular thickening, ≥5 mm, with regular or irregular contours. Endometriosis was confirmed histologically (endometrial glands or stromal fibrosis), in at least one site, in 100% patients. For the most frequent localisations, sensitivity was better for MRI in USL (65.5% vs 60.7%), RCPD (70.8 vs 60.9%) and US was better for RS (81.3 vs 66.7%). Both, TVS and MRI had similar overall sensitivity (67.6%). TVS permits better accurate diagnosis of RS endometriosis but is less reliable than MRI for USL and RCPD involvement. Both, US and MRI, are accurate in the diagnosis of DIE, with no differences in overall results. TVS should be considered as the first-line imaging technique.