Breast Imaging Reporting and Data System (BI-RADS) and Mammogram Results

The standardized system of reporting breast cancer risk is called the Breast Imaging Reporting and Data System (BI-RADS). It was developed by the American College of Radiology and is a numerical scale ranging from 0 to 6 that is used in mammogram, breast ultrasound, and breast magnetic resonance imaging (MRI) reports. These screening and diagnostic tests help determine your BI-RADS score.

A BI-RADS number reveals to your healthcare providers anything that may look potentially abnormal. It can also help them quantify how concerning the finding is. A change in the number from test to test can also help your healthcare providers more clearly detect a difference between the test results.

This article will explain the BI-RADS classifications and what they mean for your health.

Breast Imaging Reports

A mammogram, a low-energy X-ray examine of the breasts for diagnosis and screening, is the most common breast imaging test. It is often used in breast cancer screening. A breast ultrasound or breast MRI can also help identify breast cancer, and these tests are usually ordered when further evaluation is needed after a mammogram is reviewed.

Breast imaging reports should consist of a description of your breast density and any abnormalities in your breasts or in the surrounding area. The report will include the size, location, shape, and any other details about a breast mass. It may also be compared to previous images, especially if you have ever had a concerning mass in the past.

One section on your report includes your BI-RADS score, which indicates the radiologist's opinion about the absence or presence of breast cancer. Your score provides details about the possible diagnosis and whether additional testing is necessary.

BI-RADS Classifications and What They Mean

Your BI-RADS score is a number between 0 and 6. Each number corresponds to a classification that estimates your breast cancer risk based on the imaging test.

Category 0: Incomplete

A score of 0 means that your mammogram or ultrasound didn't provide enough information for a clear diagnosis. This does not necessarily mean your healthcare provider is worried about breast cancer.

This designation requires a follow-up imaging study, such as a mammogram or ultrasound obtained with special views, or a breast MRI. Your report may be classified with a 0 rating if a palpable breast lump isn't imaging clearly, if scar tissue from a previous biopsy or surgery is interfering with the image, or if your breasts are dense.

Category 1: Normal

A score of 1 means that you do not have any suspicious masses or calcifications and your breast tissue looks healthy.

Category 2: Benign

A score of 2 is given when your breast tissue looks normal and any cysts, fibroadenomas (noncancerous tumors), or other masses appear benign.

Category 3: Probably Benign

A score of 3 refers to a finding of uncertain significance. Short-term follow-up is ordered to make sure that the finding remains stable.

Category 4: Possibly Malignant

A score of 4 is reported when there are one or more suspicious lesions, masses, or calcifications. A breast biopsy is often recommended to check the suspicious area.

Category 5: Malignant

A score of 5 means that there is a mass (or more than one mass) with an appearance of cancer. A biopsy is recommended to make an accurate diagnosis.

It's important to note that even though this category is described as "malignant," masses may appear cancerous but are related to a benign condition instead. Conditions such as adenosis, fat necrosis, radial scars, and mastitis can sometimes look like cancer on a mammogram.

Category 6: Malignant Tissue

Category 6 is only used if tissue from a biopsy has been examined and found to be cancerous. If this is the case, treatment is necessary. This can include surgery, chemotherapy, and/or radiation. The imaging test is being obtained as part of the treatment or follow-up plan.

BI-RADS Scoring and Breast Density

BI-RADS reports also score breast density, which assesses how much fatty, glandular, and fibrous tissue you have in your breasts. Dense breast tissue can make it harder to detect breast cancer on a mammogram and also raises the risk of developing breast cancer.

On a mammography report, breast density is assigned to one of the following four categories:

• Category A: The breasts are almost entirely fatty.
• Category B: There are scattered areas of fibroglandular density.
• Category C: The breasts are heterogeneously dense, which may obscure small masses.
• Category D: The breasts are extremely dense, which lowers the sensitivity of mammography.

Limitations of BI-RADS

For younger women, children, and adolescents, the BI-RADS score may not be reliable.

It's also important to note that your BI-RADS score doesn't replace the opinion and insight of your healthcare provider or radiologist regarding your imaging tests. The number is not a substitute for a clinical exam.

Summary

Your BI-RADS score is there to help your doctor discuss your breast cancer risk with you and what your results mean. The score also allows your healthcare provider to compare results over time and determine whether additional, definitive testing is necessary. It does not replace a thoughtful analysis by a radiologist or a clinical exam, and it may not be reliable for everyone.

Talk with your healthcare provider about your BI-RADS score and what it means for your health and future screenings or treatment.

A Word From Verywell

Some breast images do not fit neatly into BI-RADS categories, and there may be a wide variety of findings even within the categories. While you may want to quickly find your BI-RADS number to make a conclusion about your health, it is important that you discuss your results with your healthcare provider—even if your breast imaging test turns out negative.

Screening mammograms are considered the most effective way to identify early-stage breast cancer and to get the most timely and definitive treatment. It is important to follow the guidelines for recommended screening tests, and follow-up tests if recommended. The BI-RADS score is a useful way to compare and standardize breast imaging studies. Just remember that it is only one of the many tools that your medical team uses to assess your health.