BIRADS Scores: A Standardized Classification System for Breast Imaging
BIRADS (Breast Imaging Reporting and Data System) scores are a standardized classification system developed by the American College of Radiology (ACR) to categorize breast imaging findings based on their likelihood of malignancy, guiding further management decisions. 1
BIRADS Categories
Category 0: Incomplete Assessment - Needs additional imaging evaluation and/or prior mammograms for comparison. Typically used in screening situations when additional views or ultrasound are needed for complete assessment. 1
Category 1: Negative - No abnormalities found. The breasts are symmetric with no masses, architectural distortion, or suspicious calcifications present. 1
Category 2: Benign Findings - Negative mammogram with benign findings such as calcifying fibroadenomas, oil cysts, lipomas, intramammary lymph nodes, vascular calcifications, implants, or architectural distortion clearly related to prior surgery. 1
Category 3: Probably Benign - Findings have less than 2% likelihood of malignancy. Short-interval follow-up (usually 6 months) is recommended to ensure stability. Examples include grouped round calcifications, oval circumscribed masses, and nonpalpable asymmetries. 1, 2
Category 4: Suspicious Abnormality - Findings warrant biopsy consideration. Risk of malignancy is widely variable but greater than category 3 and less than category 5. 1, 3
Category 5: Highly Suggestive of Malignancy - Findings have a high probability (≥95%) of being cancer. Examples include spiculated masses or malignant-appearing pleomorphic calcifications. 1, 4
Category 6: Known Biopsy-Proven Malignancy - Added in the fourth edition of BI-RADS for lesions confirmed to be malignant through biopsy but before definitive therapies. 1
Clinical Application and Follow-up Recommendations
For Screening Results:
BIRADS 1-2: Resume routine screening mammography in 1 year. 1
BIRADS 3: Diagnostic mammograms at 6 months, then every 6-12 months for 1-2 years. If stable or resolved, resume routine screening. If changes occur, proceed to biopsy. 1
BIRADS 4-5: Tissue diagnosis using core needle biopsy (preferred) or needle localization excisional biopsy with specimen radiograph. 1
BIRADS 6: Management according to breast cancer treatment guidelines. 1
Important Considerations
The overall BIRADS assessment is based on the most worrisome findings when multiple abnormalities are identified. 1
When both mammography and ultrasound are performed, the BIRADS categories represent the cumulative findings of both imaging modalities. 1
The BIRADS assessment category may change based on subsequent imaging findings (increase, decrease, or remain the same). 1
Pathology-imaging concordance is essential when biopsies are performed. When pathology and imaging are discordant, repeat imaging and/or additional tissue sampling is recommended. 1
Studies have shown that proper application of BIRADS 5 should yield a positive predictive value of ≥95% for malignancy, with at least four suspicious imaging descriptors typically present. 4
BIRADS 3 should not be used in screening studies without a comprehensive diagnostic evaluation that may reveal suspicious features or downgrade a finding to benign. 2