Doctors use mammograms to see potential abnormalities in your breast tissue. These abnormalities tend to appear as white 'calcifications', white bursts or white masses and can easily be spotted against the grey backdrop of the mammogram. However, if your breast tissue is very dense, doctors aren’t able to see the abnormalities as easily.
If you have dense breast, you should maintain your two-yearly screenings. However, you may need to supplement your mammogram with an ultrasound or consider a breast MRI if your breast density is high.