Understanding BI-RADS Assessment Categories for Breast Ultrasound Recalls
When a patient is recalled from a screening mammogram for a breast ultrasound, one of the most important responsibilities of the breast ultrasound technologist is understanding the purpose of the examination and the significance of the radiologist's final BI-RADS assessment. While technologists do not assign BI-RADS categories, recognizing what each category represents helps improve scanning technique, lesion documentation, and communication with the interpreting radiologist.
The Breast Imaging Reporting and Data System (BI-RADS), developed by the American College of Radiology (ACR), provides standardized terminology and assessment categories that help ensure consistent patient management and follow-up recommendations. During a diagnostic breast ultrasound, the imaging findings contribute to the final BI-RADS category assigned by the radiologist.
BI-RADS Categories Commonly Encountered During Ultrasound Recalls
BI-RADS 0 – Incomplete
A BI-RADS 0 assessment is assigned after a screening mammogram when additional imaging is needed. This is the most common reason patients are recalled for a diagnostic breast ultrasound. The ultrasound examination helps further characterize the area of concern before a final assessment can be made.
BI-RADS 1 – Negative
No sonographic abnormalities are identified. The area of concern has no corresponding ultrasound finding, or the breast tissue appears entirely normal. Routine screening is typically recommended.
BI-RADS 2 – Benign Finding
A definitely benign finding is identified, such as a simple cyst, intramammary lymph node, or lipoma. No additional follow-up beyond routine screening is required.
BI-RADS 3 – Probably Benign
The finding has a very high likelihood of being benign (greater than 98%), but short-term imaging follow-up is recommended to document stability. Many oval, circumscribed, parallel masses with benign imaging characteristics fall into this category.
BI-RADS 4 – Suspicious Abnormality
A suspicious finding is present that warrants tissue sampling. BI-RADS 4 lesions have a wide range of malignancy risk and are often subdivided into:
4A: Low suspicion
4B: Moderate suspicion
4C: High suspicion
Ultrasound-guided biopsy is commonly recommended for these lesions.
BI-RADS 5 – Highly Suggestive of Malignancy
The imaging features are highly suspicious for cancer, with a greater than 95% likelihood of malignancy. Prompt tissue diagnosis and appropriate management are recommended.
BI-RADS 6 – Known Biopsy-Proven Malignancy
This category is used when malignancy has already been confirmed by biopsy before definitive treatment. Ultrasound may be performed to evaluate disease extent, treatment response, or assist with surgical planning.
Why Understanding BI-RADS Matters for Ultrasound Technologists
Although assigning BI-RADS categories is the radiologist's responsibility, understanding the assessment system helps technologists perform more focused examinations, anticipate the radiologist's needs, and appreciate why certain imaging features require additional documentation or biopsy recommendations. A solid understanding of BI-RADS also improves communication within the breast imaging team and ultimately contributes to high-quality patient care.
