Breast cancer is the result of cells within the milk-producing lobules or the ducts of the breast developing genetic mutations that cause them to grow abnormally quickly. Because breast cancer can be more easily treated when it is caught early, screening tests such as mammograms and MRIs have been developed for early diagnosis.
MRI Technology
MRI, which stands for magnetic resonance imaging, is a powerful diagnostic tool that allows for the visualization of tissues in the human body. An MRI machine uses powerful magnets that move back and forth, creating a faint subatomic signal within the human body. These signals can be detected using radio waves. The signals are then transmitted to a computer that uses them to generate an image of the inside of the breast tissue. Although early MRI machines were not particularly effective at taking images of breast tissue, the American Cancer Society notes that specially designed machines have improved the quality of MRI breast imaging.
Advantages
One of the main advantages of using a MRI exam for diagnosing breast cancer is that it is extremely sensitive, which allows it to detect smaller growths or abnormalities in a woman's breast than a mammogram, the American Cancer Society notes. Mammograms also can be ineffective at diagnosing breast cancer in women with breast implants. MRI scans, on the other hand, can easily visualize both the implant and the surrounding tissue, Imaginis explains.
Staging and Treatment Guiding
MRI exams also can determine how far the cancer has spread, which is a process known as staging. Consequently, women who have been diagnosed with breast cancer may receive an MRI to better visualize the tumor, which can allow doctors to determine if the tumor is confined to one part of the breast or if it has begun to migrate to the surrounding tissues. More accurate tumor staging, the American Cancer Society explains, can help guide treatment and can help doctors decide if more aggressive surgery is needed.
Disadvantages
Although an MRI diagnosis of breast cancer is sensitive, that sensitivity can be a problem, the Mayo Clinic explains. MRIs of the breast can identify areas that appear suspicious but that are ultimately found to not be cancerous. This is known as a false positive, and it can cause large amount of unnecessary anxiety. False positives can also cause unnecessary biopsies of the breast. In addition, an MRI of the breast is more expensive than a mammogram and may not be covered by some insurance plans.
Recommendations
MRI screening for breast cancer is best used for younger women who are at a higher risk of developing breast cancer, according to the American Cancer Society. Women may be deemed high risk if they have a family history of breast cancer or if they have specific genetic mutations that predispose them to developing breast cancer. In these cases, the MRI is far better at detecting cancerous tissue early, and it is better at imaging the denser breast tissue of younger women. Although women who have an average risk of developing breast cancer can still get an MRI, current research does not show that it is an appropriate tool for screening.
