Breast Density 101

Aug 8, 2018
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There is a wide range of normal appearances to breasts, both visually and on mammography. One of the important ways breasts differ in mammography is breast tissue density. Breasts are composed of many types of tissues including fat, supporting structures like cooper’s ligaments, vessels, nerves, and glandular tissue. The glands that produce milk and the fibrous supportive tissue are collectively called “fibroglandular tissue” which appears dense on x-rays called a mammogram. Some breasts are mostly fatty and some breasts are mostly dense, with the majority somewhere in the middle. The way breasts look and feel does not predict whether or not they are dense on mammography. 

How Does a Women’s Breast Tissue Density Change?

Your breast tissue density changes with age. The breast bud starts to be visible in a developing adolescent usually between ages eight to twelve development may be hereditary or a result of external or hormonal influences such as increased body mass index (BMI) in which the extra fatty tissue exerts increased hormonal influence on the breasts. In young women before the reproductive years, the breast density is typically at its greatest. If or when a woman gives birth, the age of one’s first live birth may predict the breast density for much of one’s premenopausal life. For example, a woman who has her first baby at age 18 is much more likely to develop fatty breasts earlier than a woman who has her firstborn at 30. Some women never have children (we call this nulliparous) and therefore, the breast tissue never becomes less dense. 

Why is Breast Tissue Density Important?

A woman’s breast tissue density is important for two reasons. First, dense breast tissue can hide underlying breast cancer since the fibroglandular tissue is white on a mammogram and so are breast cancers. So a woman with dense breast tissue has an increased rate of cancer going undetected. Radiologists specialized in reading mammograms called women’s imagers or women’s imaging radiologists will use various imaging studies to try to see through the dense tissue. A 3D mammogram can increase the detection of some types of breast cancers in heterogeneously dense breasts. There are four categories of breast tissue identity based on the proportion of fat to dense tissue: fatty, scattered fibroglandular, heterogeneously dense, and extremely dense. For women with extremely dense tissue, a 3D mammogram may not increase the detection of breast cancer; other imaging studies are needed such as breast ultrasound. Breast ultrasound excels at detecting small breast lumps like breast cysts, fibroadenomas (benign fibrous nodules), and breast cancer because all of these findings are dark on a bright background, almost the reverse of a mammogram. 

Women with dense tissue not only have a harder time finding cancer by a mammogram, but the dense breast tissue may also be its own risk factor. We know that women who do not have children by a certain age or not at all are at increased risk of breast cancer because the tissue never goes through its full development cycle. Also, breast tissue density may be inherited so if your mother or sisters had dense tissue, so may you. Since most women have dense breast tissue naturally when they are younger and premenopausal (before menopause), we cannot truly assess tissue density and one’s risk density until after we see what pattern emerges after menopause.  Women with dense breast tissue have up to six times (6X) increase in developing breast cancer over their lifetime so it’s important that we use other imaging studies to increase the detection of breast cancer for all women. For women with a strong family history of breast cancer, a breast MRI may be used to find small breast cancers that are not seen on a mammogram. Insurance controls the use of breast MRI for appropriateness so if you think that you may be eligible for MRI, we encourage you to talk with your referring physician. The script or referral your clinician gives you to The Women’s Imaging Center starts the process, then our specialized staff works with your insurance to obtain the authorization. We offer affordable low-cost self-pay rates for all our affordable MRI imaging studies for women (or men) who desire a low-cost MRI that your physician has ordered. See my previous related blog article on MRI uses.

What Sets Us Apart From Other Centers for Women’s Imaging?

The Women’s Imaging Center is proud to announce that it uses the 3D Mammogram imaging at our Women’s Imaging-Denver/Cherry Creek location, our Women’s Imaging -West/Lakewood, Women’s Imaging-South/Highlands Ranch locations, and our Westminster location uses the highly rated digital mammography system made by Hologic Selenia. The Women’s Imaging Center offers bilateral whole breast ultrasounds for women with dense tissue at all of our locations throughout the Denver area. “The Women’s Imaging Center” provides low-cost imaging services in an outpatient setting and is the only imaging center to provide Women’s Imaging from screening to diagnosis to a non-surgical breast biopsy in an outpatient setting instead of moving the patient to a more expensive hospital or Ambulatory Surgical settings. 

Our physicians Dr. Kelly McAleese, Dr. John Lewin, and Dr. Timothy Colt are fellowship-trained specialists in Women’s Imaging.

The Women’s Imaging Center is proud to offer 3D Tomosynthesis Mammography at our Denver/Cherry Creek, West-Lakewood, and South-Highlands Ranch offices. Westminster uses highly-rated digital mammography systems made by Hologic Dimensions. We offer whole breast ultrasound for increased detection with dense breast tissue at all of our Women’s Imaging Center locations and offer breast MRI and body MRI at our Women’s Imaging-Denver/Cherry Creek location.

The Women’s Imaging Center

Call 303-321-CARE (2273) to schedule an appointment or make an online appointment request.

The Women’s Imaging Center is committed to providing individualized, innovative, state-of-the-art healthcare to women.

Kelly McAleese
by Kelly McAleese