Mammography uses an X-ray, where MRI, short for magnetic resonance imaging, uses radio waves and a powerful magnet linked to a computer to create detailed pictures of areas inside the body.
Mammography is an excellent tool for screening women at average risk for breast cancer It is easily accessible and less expensive than MRI.
Recent studies show that MRI is a great complement to mammography, especially in women who have been diagnosed with breast cancer. MRIs are now used most often as an adjunct to screening mammography in women who are at very high lifetime risk for breast cancer. It is also used to evaluate extent of disease in the newly diagnosed cancer patients, and can help guide treatment options. Breast MRI also detects unsuspected cancer in the opposite breast in 3 to 4 percent of these women. But at the present time, breast MRI is not considered a replacement for annual screening mammography.
In 2003, the American Society of Clinical Oncology reported on three studies that examined MRI screening for women who are at high risk for breast cancer. These studies concluded that MRI is a more sensitive in finding cancers than mammography, ultrasound, or clinical breast exams, however, it was revealed that MRIs give a higher number of “false positives,” too, which in turn can mean unnecessary tests, biopsies, and increased anxiety.