ACR BI-RADS MRI Category

Category 0 : need additional imaging evaluation

Category 1 : negative

Category 2 : benign findings

Category 3 : probably benign finding - short interval follow up suggested ( <2%)

Category 4 : suspicious abnormality - biopsy should be considered
　　　　　　　　4A (2～32%)
　　　　　　　　4B (33～66%)
　　　　　　　　4C (67～94%)

Category 5 : highly suggestive of malignancy - appropriate action should be taken ( >95%)

Category 6 : known biopsy-proven malignancy - appropriate action should be taken (100%)


( possibility of malignancy )