My technician recently told me, just before sending me gliding through an MRI tube, that MRI scans were once an uncommon breast exam. He performed the breast scans only a few times per month, when radiologists needed to get a better read on potential breast cancers than they could from mammography alone.
Now my tech performs the highly sensitive breast exam, which uses magnetic and radio waves to create layers of black and white breast images, all the time. He told me his MRI suite—with just two machines—now has a companion facility on the same hospital grounds, due to increased demand.
There is more need for breast MRIs, he said, and with the new American Cancer Society (ACS) recommendation—certain women with high risk of developing breast cancer should get MRI scans in addition to their yearly mammogram—it seems the demand for these machines will keep climbing.
In March 2007, the ACS announced that breast MRI and mammogram, when used together, give doctors a better chance of finding breast cancer early in high-risk women, when it’s easier to treat, when survival outcomes are more hopeful.
MRI—also known as magnetic resonance imaging—uses a large magnet and radio waves to measure several properties of tissue in the breast. It creates very precise images and can sometimes detect cancers that may never be seen on mammograms. It can miss some cancers too. MRI scans cannot pick up on tiny specks of calcium, also known as microcalcifications, which account for some of the cancers detected on mammograms.
False positives are another downside to MRI. The scans are more likely to show spots in the breast that may not be cancer. Since there is no definite way of knowing whether or not a spot is cancerous, a biopsy or other invasive breast exam procedure becomes necessary. To protect women with average risk of breast cancer from the pitfalls of false positive results, MRI is only recommended for women at high risk for the disease.
These high-risk women—profiled below—should begin getting MRIs and mammograms beginning at age 30, according to the new ACS guidelines.