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Frequently Asked Questions

what are dense breasts

What are Dense Breasts?

Generally, younger women have denser breast tissue than older postmenopausal patients. Patents with more body fat or having had multiple births in the past tend to have less dense breasts. Yet, many women have dense breasts well into their 70s and 80s. To explain the concept of breast density, we developed a model based on the image of a tree.

Let's take a picture of a tree in February when no leaves are on the branches. Any nest, bird, squirrel, etc., are easily identified. A broken branch is seen immediately. Nothing is hidden except something small that might be growing within a branch. This tree is "not dense."

If you take a picture of the same tree in August, the branches are covered with leaves. There are hundreds of birds, nests, and other animals that cannot be identified from a distance. Without looking closer or pushing the leaves out of the way, it isn't easy to discern what is occurring on and in the branches. This tree is "dense."

In some women, the breast density never diminishes. We call them "evergreen tree" type breasts. Both pictures need to be evaluated very differently. Of course, there is a spectrum. The tree has different densities in each season and requires varying degrees of sensitivity to detect anything on the branches.


This analogy provides insight into breast density in mammography. Patients with significant breast density may benefit from a closer look at the structure of the breast ultrasounds, tomosynthesis, MR, or breast-specific gamma imaging. This model helps patients understand why some women detect lumps that are not identified mammographically and why the mammogram is sufficient for some women and not others.


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