The Breast Imaging Reporting and Data System (BI-RADS) is a standardized system to describe mammogram findings and results. Developed by the American College of Radiology (ACR), results of mammograms are sorted into categories numbered 0 through 6 with interpretation as follows:

Category 0: Additional imaging evaluation and/or comparison to prior mammograms is needed.

Category 1: Negative.

Category 2: Benign (noncancerous) finding.

Category 3: Probably benign finding—Follow-up in a short time frame is suggested.

Category 4: Suspicious abnormality—Biopsy should be considered.

Category 5: Highly suggestive of malignancy—Appropriate action should be taken.

Category 6: Known biopsy-proven malignancy—Appropriate action should be taken. ■