Pathology and risk stratification-based evaluation of ovarian masses on MRI

Characterisation of an indeterminate ovarian mass is important as it guides management and clinical outcomes. Ultrasound is the first-line modality in the assessment of ovarian tumours. When ovarian masses are indeterminate on ultrasound, MRI provides excellent resolution in tissue characterisation and enhancement patterns. Ovarian masses can be categorised based on risk-scoring systems such as the American College of Radiology (ACR) MRI Ovarian-Adnexal Reporting and Data System (O-RADS). The imaging features of non-neoplastic, benign, borderline and malignant neoplastic ovarian lesions are discussed in this review with a focus on the pathology process accounting for the MRI appearance. Characteristic findings and clues in differentiating a benign lesion from a malignancy are presented in this review.