Use of the probably benign (BI-RADS category 3) assessment for masses on breast MRI: Is it transferable to general clinical practice?

The purpose of this study was to identify potential BI-RADS 3 mass descriptors on breast magnetic resonance imaging by systematically defining positive predictive values (PPV). In a blinded retrospective review of BI-RADS 4 masses, reader 1 identified 132 masses and reader 2 identified 76 masses. PPV for mass descriptors and for descriptor combinations was determined. No mass descriptor resulted in a PPV ≤2% (BI-RADS 3 threshold). Descriptors with the lowest PPVs were circumscribed margin (8%), rim internal enhancement and persistent kinetics (13% each), and oval shape (15%). The results demonstrate the difficulty in transferring the theoretical concept of lesion surveillance to systematic clinical use.