BI-RADS (Breast Imaging-Reporting and Data System) is a standardized grading system used globally by radiologists to report mammogram, ultrasound, and MRI results. It provides a universal language to describe how suspicious a finding is and what the next step should be.

The scale ranges from 0 to 6. For example, a score of 1 or 2 means the findings are benign and routine screening is recommended. A score of 3 indicates a probably benign finding requiring short-interval follow-up. A score of 4 (subdivided into 4A, 4B, and 4C) means the finding is suspicious and a biopsy is recommended. BI-RADS also grades breast density from A (fatty) to D (extremely dense). It is crucial to discuss your BI-RADS score with a breast surgeon, as clinical context—such as family history or symptoms—heavily influences the recommended action.

Frequently Asked Questions

What is breast density and why does it matter?

Breast density describes the relative amount of different tissues seen on a mammogram — it is not related to breast size or firmness. Breasts are made up of glandular tissue (which produces milk), connective tissue, and fatty tissue. Women with dense breasts have more glandular and connective tissue and relatively little fat.

Density matters because of how tissue appears on a mammogram. Fatty tissue looks transparent, making it easy to see through. Dense tissue looks solid white — and so does breast cancer, which means a cancer can be harder to spot in dense breasts. The only way to know if you have dense breasts is to have a mammogram.

Breast density is often inherited but can change over time. Women with dense breasts have a somewhat higher risk of breast cancer and may need closer follow-up — the doctor may recommend an ultrasound in addition to mammography to evaluate dense breasts more thoroughly.