EP23.09: Characterisation of ovarian masses using pelvic magnetic resonance imaging: the prospective IOTA‐MRI study

The aim of this study was to evaluate the diagnostic accuracy of pelvic magnetic resonance imaging (MRI) using the ADNEXMRSCORING system in differentiating adnexal masses as benign or malignant if the IOTA Simple Rules (SR) are inconclusive. This prospective international multicentre study was conducted between 2017 and 2023, enrolling patients with adnexal masses that could not be clearly categorised by SR and were scheduled for surgical intervention. We report interim analysis results for patients included between February 2017 and December 2022. After ultrasound assessment, patients underwent diffusion and perfusion-weighted pelvic MRI, and surgical removal with histological examination of the mass. The primary aim was to determine the sensitivity, specificity, and area under the receiver operating characteristics curve (AUC) of the ADNEXMRSCORING system for the differentiation between benign and malignant adnexal masses. Initially, 286 patients from nine centres were recruited. After excluding ineligible cases and centres with low inclusion rates, 211 patients from six centres were included in the interim analysis. Histological examination revealed that 61% of the masses were benign, 17% were borderline, 16% were malignant and 6% were metastatic. The ADNEXMRSCORINGsystem had an AUC of 0.83 (95% CI; 0.77-0.88). Using an ADNEXMRSCORE cut-off of 2-3 for benign masses and 4-5 for malignant masses, MRI showed a sensitivity of 72% (95% CI: 61.4%-80.5%) and a specificity of 85.3% (95% CI: 78.1%-90.4%) to detect malignancy. In conclusion, pelvic MRI complemented by the ADNEXMRSCORING system offers a promising diagnostic second line approach to differentiate benign from malignant adnexal masses in cases where SR results are inconclusive. These findings highlight the potential clinical utility of this combined modality in improving diagnostic accuracy and guiding appropriate management strategies for patients with ‘difficult’ adnexal masses.