Introduction The aims of this study were to assess the outcomes of ovarian masses after the introduction of the Ovarian-Adenexal Imaging-Reporting-Data System (ORADS). This system allows a standardised classification of ovarian lesions. It consists of two classifications for ultrasound and magnetic resonance imaging. The aim is to optimise cancer outcomes and reduce unnecessary surgery. ORADS has been shown to have similar sensitivities as the IOTA simple rules and ADNEX model but has the advantage of assigning management.

Methods Ultrasound and MRI ORADS scores of 1-5 over the period of one year from the 1st october 2022 to the 30th september 2023 were assessed along with histology outcomes.

Results 777 patients had ultrasound ORADS scores of 1-3. 96 patients had ultrasound ORADS scores of 4-5. Of the USS ORADS score 4, 38.0% were benign, 13.9% were borderline or malignant, the rest were downgraded on MRI. Of the MRI ORADS 4, 62.5% were benign, 37.5% were malignant. Of the USS ORADS score 5, 25% were benign, 50% were borderline or malignant and the rest were downgraded on MRI. Of the MRI ORADS 5, all were malignant. The sensitivity of ultrasound was 92% with a specificity of 59%, and the sensitivity of MRI was 86% with a specificity of 96% to differentiate between benign and malignant masses.

Conclusion/Implications The diagnostic performance of both ultrasound and MRI for benign and malignant masses was high. MRI should be considered as the next in line investigation over CT by the multidisciplinary team to help downgrade lesions and avoid more extensive surgery.