BI-RADS — What It Means on Your Imaging Report
Quick Answer
BI-RADS is a scoring system (0–6) used to classify mammogram and breast ultrasound findings — the number tells your doctor what to do next, from "routine screening" to "highly suspicious."
What Is BI-RADS?
BI-RADS stands for Breast Imaging Reporting and Data System. It was developed by the American College of Radiology (ACR) to create a standardized way for radiologists to communicate mammogram and breast imaging findings. Instead of using vague language, every radiologist assigns a category from 0 to 6, so your doctor knows exactly what the findings mean and what action to take.
The system has been in use since 1993 and is the global standard for breast imaging reports. If you have had a mammogram, breast ultrasound, or breast MRI, your report will include a BI-RADS category.
Categories / Classification
| BI-RADS | Assessment | What It Means | Recommended Action |
|---|---|---|---|
| 0 | Incomplete | The images need additional evaluation | Additional imaging (extra mammogram views, ultrasound, or MRI) |
| 1 | Negative | No abnormalities found | Continue routine screening (typically every 1–2 years) |
| 2 | Benign | A non-cancerous finding (such as a cyst or calcification) | Continue routine screening — no further action needed |
| 3 | Probably Benign | Very likely not cancer (over 98% chance of being benign) | Short-interval follow-up, usually in 6 months |
| 4 | Suspicious | A finding with features that raise concern | Biopsy recommended. Category 4 is subdivided into 4A (low suspicion, 2–10%), 4B (moderate, 10–50%), and 4C (high, 50–95%) |
| 5 | Highly Suspicious | Very strong probability of cancer (over 95%) | Biopsy is essential before treatment planning |
| 6 | Known Cancer | Cancer has already been confirmed by prior biopsy | Used for tracking during treatment (e.g., monitoring response to chemotherapy) |
When You Might See This on Your Report
BI-RADS appears on:
- Mammogram reports — the most common context
- Breast ultrasound reports — often used alongside mammography
- Breast MRI reports — typically for high-risk patients
Every breast imaging report is required to include a BI-RADS final assessment category. You will usually find it in the Impression or Assessment section at the bottom of the report.
Should I Be Worried?
It depends on the category:
- BI-RADS 1 and 2 mean everything is normal or clearly benign — no cause for concern.
- BI-RADS 3 means the finding is almost certainly benign (over 98% probability), but your doctor wants to monitor it with a follow-up scan in about 6 months to confirm it has not changed.
- BI-RADS 0 simply means the radiologist needs more images to make a decision — it is not a cancer indicator.
- BI-RADS 4 and 5 do require a biopsy to determine whether the finding is cancerous. However, according to the American Cancer Society, approximately 80% of breast biopsies come back benign. A biopsy recommendation does not mean you have cancer — it means your doctor needs more information.
What Should I Do Next?
- Check the BI-RADS number in the Impression or Assessment section of your report.
- Follow the recommended action for your specific category (see the table above).
- Talk to the doctor who ordered the exam — they will explain the findings in the context of your personal health history and risk factors.
- If a biopsy is recommended, ask about the type of biopsy, what to expect, and the timeline for results.
- Keep copies of your imaging reports so future scans can be compared with prior results.