A: Every breast anatomically represents a combination between fatty tissue (which appears black on the mammogram) and fibroglandular tissue (which appears white on the mammogram). When a mammogram is read by the Radiologist, the degree of fibroglandular tissue is reported in quartiles: (a) “fatty” (0-25% fibroglandular tissue), “scattered fibroglandular” (25-50% fibroglandular tissue), “heterogeneously dense” (50-75% fibroglandular tissue), “extremely dense” (75-100% fibroglandular tissue). When a Radiologist reads your mammogram, they are looking for abnormalities that appear of high density and that are mostly “white”. Therefore, in an extremely dense breast, it is as if one is looking for a snowman in a snowstorm. Masses can be hidden or obscured in heterogeneously dense or extremely dense breasts and this is why it is especially important for women with dense breasts to receive 3D mammograms and discuss adjunct screening such as whole breast ultrasound with their providers. However, notably, the scientific literature is very clear that 3D mammograms are superior regardless of the breast density. Therefore, in our health care system, nearly 100% of our patients receive 3D mammograms.