What does BI-RADS grading mean? The American Association of Radiology established the Breast Imaging Reporting and Data System (BI-RADS) in order to standardize the evaluation of mammography images. The current version of BI-RADS is the 2003 fourth edition, which is also used for ultrasound and MRI reports. 2003 American Radiological Society Breast Imaging Reporting and Data System (BI-RADS) Diagnostic Grading Grade 0: Requires additional imaging. Grade 1: Negative Grade 2: Benign. Includes fibroadenomas that have calcified, multiple secretory calcifications, lesions with a fatty component, intramammary lymph nodes, and implanted prostheses. Grade 3: Possibly benign, short-term follow-up observation is recommended. (Possibility of malignancy is less than 2%, short-term follow-up generally means six months) Including non-calcified well defined lumps and clusters of punctate calcifications Grade 4: Suspicious of malignancy, biopsy is recommended. Grade 5: Highly suggestive of malignancy and should be managed appropriately. The likelihood of malignancy is greater than 95%. Grade 6: Biopsy has confirmed malignancy.