BI-RADS (Breast Imaging Reporting and Data System)

The American College of Radiology's BI-RADS manual gives radiologists one vocabulary, report structure and final assessment category for mammography, breast ultrasound and breast MRI; the current release is the illustrated v2025 manual, an extension of the fifth edition of the atlas.

The National Cancer Institute's mammogram fact sheet sets out what each category means and what follows it: 0, more imaging is needed before a category can be given; 1, negative, and 2, a benign finding, both mean continuing routine screening; 3, probably benign, means a repeat mammogram in six months; 4, a suspicious abnormality, may need a biopsy; 5, highly suggestive of cancer, needs a biopsy; and 6 is used for a cancer already proven by biopsy, before treatment starts. The report also states breast density. Since 1999 every woman in the United States who has a mammogram must be sent a written result in plain language.