EP31.06: Agreement between transvaginal ultrasound and magnetic resonance imaging in diagnosing deep endometriosis

Transvaginal ultrasound (TVS) and magnetic resonance imaging (MRI) are two non-invasive methods for diagnosing ovarian and deep endometriosis (DE). The aim of this study was to assess the agreement between TVS and MRI in diagnosing endometriomas and DE. Observational cross-sectional study of patients undergoing TVS at ultrasound unit with expertise in endometriosis and MRI at the Department of Radiology between 2019-2022. Endometriosis findings at TVS were described using terms and definitions according to the International Deep Endometriosis Analysis (IDEA) consensus. Endometriomas and DE findings for each location at TVS and MRI were compared. In total, 40 women were included. There was good agreement between TVS and MRI for endometriosis, deep pelvic endometriosis, and ovarian endometriomas (p < 0.001). Endometriosis was seen in 25 (65%) of women at TVS and 27 (70%) at MRI. There was significant agreement between TVS and MRI for presence of bowel DE, but significantly more bowel lesions were seen at TVS (16 patients, 19 lesions in total) than at MRI (11 patients, 11 lesions in total). TVS and MRI showed poor to moderate agreement in diagnosing deep endometriosis of the uterosacral ligaments (USL) and vagina wall. Endometriosis lesions in other locations were rare. Description of endometriosis findings at MRI was not systematic. Agreement between TVS and MRI in detecting endometriosis varies depending on localisation of endometriosis lesions. Due to difficulties in comparing findings at TVS and MRI, a standardised approach for TVS and MRI reports would benefit interprofessional communication. Further studies with greater sample sizes, mutual terminology, and comparison with surgical findings are needed.