Introduction/Background Adnexal lesions range from benign and simple cysts to borderline and malignant tumors. Determining how to treat these masses requires the use of highly accurate diagnostic tools. It is imperative to use a tool that helps accurately diagnose the extent of the disease and choose the optimal treatment approach. The study aimed to evaluate the accuracy of ultrasound (US) compared with MRI and the results of both compared with postoperative pathology of adnexal tumors.

Methodology This prospective cohort study included 84 women with at least one adnexal lesion detected by US who underwent surgery at our hospital. MRI and transvaginal (TV) US-O-RADS grading systems were calculated for all patients preoperatively, and the results were compared to postoperative pathology reports using detection rate (DR) values.

Results About 65.5% of the adnexal masses were benign, and 34.5% were borderline/malignant. The correlation between MRI and TV US O-RADS scores was significantly (p-value<0.001) acceptable (r=0.637). Although the highest TV US and MRI O-RADS DR values were in malignant tumors, all DRs were less than 50%.

Conclusion It seems that TV US can replace MRI when performed by an expert radiologist. Although both TV US and MRI O-RADS scores had low DR in differentiating between benign and malignant tumors, having an almost 50% chance of malignancy is enough to refer the patient to an expert institute with gynecologic oncologists and accessible intraoperative frozen section consultation to decrease the severe consequences of incomplete staging.

Disclosures None.