What are dense breasts ?

Dense breasts have a higher proportion of glandular tissue compared to fatty tissue. The relative ratio of glandular to fatty tissue varies among women. As women age, their breasts tend to become less dense.

The main significance of this is in screening mammography, which is less sensitive in identifying lesions accurately under these circumstances. Dense breast tissue appears as a solid white area on a mammogram film, and fat appears as a dark area. X-rays do not penetrate or "see through" dense tissues as well as they do through fat. So, in women with dense breasts, mammograms may be more difficult to interpret. In addition, tumors are also dense tissue and appear as solid white areas on the mammogram. This can make it more difficult to detect a tumor in dense breasts because it looks a lot like the dense tissue that surrounds it.

Digital mammography does a better job detecting cancer in dense breasts than does traditional mammography. A digital mammogram produces images on a computer screen that can be enhanced and magnified for closer viewing. However, digital mammograms may not be as widely available as are traditional mammograms. Please enquire about a digital mammogram at your next breast screening appointment.

Other imaging modalities, in particular, high resolution ultrasonography and magnetic resonanc imaging are useful adjuncts for diagnosis in women with dense breast tissue. Ultrasonography however is strongly operator dependent, while MRI involves the injection of contrast agents.