What is dense breast tissue?
Dense is usually a mathematical term meaning crowded or packed or a greater number of “things” in a certain volume. What this means on a mammogram is that there is a greater proportion of whiteness to grayness in the breast. (See image comparing breast tissue types). The whiteness on the mammogram is a combination of the glandular or ductal tissue of the breast and the fibrous supporting tissue. The grey is the fatty part of the breasts. As women age, their breasts on their mammograms get more grey (like their hair) because they don’t need the milk ducts anymore. Genetic research in the past decade or so has revealed that dense breast tissue is mostly a heritable trait. But how your breasts feel doesn’t always correlate with how “dense” the tissue appears on imaging, so you won’t know you’ve inherited this feature until you get a mammogram. There’s no universal measure that quantifies breast tissue density — at least, not yet. For a while now, readers of mammograms have most commonly e
