RESEARCH QUESTIONHow do clinical rectovaginal examination and transvaginal ultrasound examination perform in the diagnosis of parametrial infiltration in patients with endometriosis?DESIGNThis was a multicentre prospective observational study. Patients with suspected deep endometriosis at clinical examination and/or at ultrasound evaluation and scheduled for surgery were included. Following multicentre multidisciplinary meetings, consensus was obtained on terms and methodology to define the parametrium at pelvic anatomy, ultrasound and surgery. Sensitivity, specificity, accuracy, and positive and negative likelihood ratios were calculated for clinical and ultrasound examinations with respect to surgery.RESULTSIn total, 195 women were selected for the present study and 164 were included in the analysis. Ultrasound examination had good to high specificity (>80%) for all parameters, except the left lateral parametrium (78.8%). The sensitivity of ultrasound examination was good to high for fixity of the right and left ovaries, uterosacral ligaments, retrocervix and rectovaginal space; and low for the anterior and lateral parametria, vagina, bladder and bowel. Clinical examination had good to high specificity for fixity of the left ovary, anterior parametrium, right uterosacral ligament, retrocervix and vagina; and low specificity for fixity of the right ovary, lateral parametrium, left uterosacral ligament and rectovaginal space. The sensitivity of clinical examination was good for the uterosacral ligaments and rectovaginal space, and low for the remaining parameters.CONCLUSIONUltrasound examination provided good specificity for all the parameters, but sensitivity was low for the anterior and lateral parametria. Clinical examination provided good specificity for the anterior and posterior parametria, but sensitivity was low for the anterior and lateral parametria. Further prospective studies are needed to validate this methodology and confirm the results.