An imaging technique called 3-T magnetic resonance imaging (3-T MRI) is more sensitive than mammography and sonography at detecting breast cancers in high-risk women, according to a review study conducted at the University of Toledo Medical Center, Toledo, Ohio.
The study’s results were published in the April 2009 issue of the American Journal of Roentgenology, a trade publication focused on the field of radiology. The findings suggest that 3-T MRI is a valuable additional tool for monitoring women at higher-than-average risk for developing breast cancer.
Mammography, or an X-ray of the breasts, is the standard tool used to screen women for breast cancer. Sonography (also called ultrasound), which sends high-frequency sound waves through the breast and converts them into images on a viewing screen, may be used in addition to mammography, especially if an area requires further investigation.
Some research has suggested that women with a higher-than-average risk of developing breast cancer should also undergo breast MRI, which uses magnets and radio waves to produce detailed cross-sectional images of the tissue. The newest type of MRI, called 3-T MRI, uses a powerful magnet that produces very detailed images. "3-T" refers to a magnet that is 3 Teslas strong, versus 1 or 1.5 Teslas for standard forms of MRI. (The Tesla is the unit of measurement for the strength of the magnet in an MRI machine.)
Study Design and Goals
Researchers reviewed the records of 434 high-risk women who underwent 3-T MRI, mammography and sonography between May 2006 and October 2007. The women had a personal history of breast cancer or a strong family history, or tested positive for a genetic mutation (BRCA1 or BRCA2) that increases risk. The average age of the women was 53 years old.
The goal of the study was to compare the accuracy of 3-T MRI, mammography and sonography in detecting disease. It did not compare standard 1.5 Tesla MRI to 3-T MRI, so this study does not show whether the newer screening works more effectively than the current standard.
This study was a retrospective review, an analysis of data collected during treatment but evaluated later.
Overall, there were 66 breast cancers found among the group. The results showed that 3-T MRI detected a significantly higher number of these cancers than mammography and sonography. 3-T MRI found 66 out of 66 cancers, or 100 percent, while mammography detected 54 out of 66 cancers (81.8 percent), and sonography, 57 out of 66 or 86.4 percent.
At the same time, 3-T MRI was more likely to result in a false positive result—that is, suggest a possible area of cancer that turned out to be benign (not cancer). Biopsies of 49 masses picked up by 3-T MRI showed that they were benign.
Researchers concluded that 3-T MRI can play a role in screening women who are at high risk of getting breast cancer.
What Does This Study Mean for Me?
If you are at high risk for developing breast cancer—whether because you’ve had it before, you have a strong family history or you tested positive for a genetic mutation that increases risk—talk to your doctor about the possibility of adding MRI to your regular mammograms. Together you can work out the screening plan that is best for you.
If you are at average risk for developing breast cancer, you can continue with your current screening plan. 3-T MRI is not recommended for all women because it is more expensive than other screening tests, and it would cause many women to undergo biopsies for unusual findings that are not really breast cancers. Talk to your doctor for more information.
H Elsamaloty et al. Increasing Accuracy of Detection of Breast Cancer with 3-T MRI. American Journal of Roentgenology 2009; 192: 1142-1148.