Instead of the X-rays used in mammography, an MRI uses magnets, radio waves, and a
computer to make many detailed pictures of the inside of the breast. You may be given a
contrast dye to better outline the breast tissue and possible tumors. The dye is put
into a vein in your hand or arm.
can find tumors that are too small to feel and may not show up on a mammogram. But an
MRI may miss some cancers that would be found on a mammogram. So it's important that
high-risk women get both tests.
reason MRIs may find these tumors is because high-risk women tend to be younger and have
denser breasts. This means that the breast has less fat and more fiber-like connective
tissue, which can block X-rays during a mammogram. An MRI is not affected by dense,
fibrous breast tissue.