Breasts are made up of different types of tissue; there are dense fibrous and glandular, and less-dense fatty tissues. Each woman has their own unique combination of these tissues. Some have enough dense tissue to be classified as having "dense breasts."
The four images above are mammograms.
Are Dense Breasts Uncommon?
No, dense breasts are not uncommon. In fact, about 50% of women have dense breasts. About 10% of women have "extremely dense" breasts, while 40% of women have a level of density called "heterogeneously dense".
How do I know if I have dense breasts?
Since April 1, 2013, California law (Senate Bill 1538; Section 123222.3 of the Health and Safety Code) requires imaging centers to notify patients who have dense breasts. The law states:
Why is breast density important?
Higher levels of density may make it more difficult for a mammographer to detect breast cancer—dense tissue is simply harder to see through on a traditional x-ray mammogram, and areas of higher density can look much like tumors.
If I have dense breasts, do I still need a mammogram?
Yes. Mammography is still the gold-standard for breast-cancer detection. In fact, there are types of cancers which only show up on mammograms. You should continue to follow the guidelines for mammography based on your age, your risk-factors, and your doctor’s advice.
If I have dense breasts, is there more that I can do?
At this time, mammography remains the only recommended breast-cancer screening exam. There are, however, secondary screening options, such as automated whole breast ultrasound. If you are interested in an automated whole breast ultrasound, you should discuss them with your regular physician.
For more information, click on What is Automated Whole Breast Ultrasound?
Source: The American College of Radiology