Mammogram Reports and BI-RADS: Category 1

Mammogram Reports and BI-RADS: Category 1

Mammography reports may seem complex to the uninitiated. Every breast imaging report will end with a final result assessing the findings and indicating what, if anything, needs to be done next. That final result is given in a uniform manner across all imaging facilities and is reported as a BI-RADS category. BIRADS stands for Breast Imaging-Reporting and Data System, which is a tool developed by the American College of Radiology to simplify breast imaging reports and their recommendations. It breaks results down into seven possible categories, from Zero to Six. We’re going to spend the rest of this week explaining the categories- what they mean and showing examples of what the different categories might look like on imaging. Today, we’re starting with negative, or BIRADS category 1.


A BI-RADS category 1 means the mammogram, breast ultrasound and/or MRI breast show no suspicious findings for cancer. “Negative” in this connotation is good – it means there are no signs to suggest breast cancer. The majority of breast imaging studies will fall in this category. With a final report of BI-RADS category 1, you can go to normal screening. For patients of average risk older than 40, this means we can see you again in 12 months for your annual screening mammogram!


There is a range of what a normal mammogram looks like, with some breasts mostly dense and others mostly fatty. Below is an example of a normal, BI-RADS category 1 negative mammogram (figure 3) and (figure 4 (dense tissue)). Your mammogram is unique – nobody will have quite the same size breasts or the same distribution of fat and glandular tissue. This is why comparison studies are so helpful – looking for change in your tissue is a valuable part in the assessment for signs of breast cancer.


Breast ultrasounds are done for many reasons including further evaluation of findings on other breast imaging tests, further evaluation of something being felt on physical exam of the breast, and in some patients for screening for breast cancer in conjunction with their mammogram. Breast tissue on ultrasound will have varying degrees of glandular and fatty tissue, again unique for you. An example of normal, BI-RADS category 1 negative breast ultrasound images is shown in figure 2.


Breast MRI is a test showing anatomy of breast tissue as well as how that tissue changes with blood flow with injection of a contrast agent. Breast MRI is used as an additional way of screening for breast cancer in certain high risk patients. It is also used as a problem solving tool, and plays an important role in some breast cancer patients to look for the extent of cancer in the breasts. With MRI, the entire breast, armpit and chest wall can be imaged, as shown below (figure 1) in this normal, BI-RADS category 1 MRI.


Now we hope you have an understanding of what exactly BI-RADS means and what a category 1 result tells you and your doctor. Stay tuned for an explanation of category 2 and more breast imaging examples.   




Originally posted 7/9/13 on