04/17/2026
Approximately 40-50% of patients undergoing screening mammogram have dense breast tissue.
About 30-40% have heterogeneously dense (BI-RADS category C) and less than 10% have extremely dense (BI-RADS category D).
Dense breast tissue makes it easier to miss small masses on mammogram so a breast ultrasound MAY be useful. However, it may also lead to unnecessary additional imaging, biopsies and increased healthcare costs.