The MRI option

MRI can be used along with mammograms for screening women who have a high risk of developing breast cancer, or it can be used to better examine suspicious areas found by mammograms. MRI is also used for women who have been diagnosed with breast cancer to better determine the actual size of the cancer and to look for any other cancers in the breast.


"I believe the breast MRI is really used once you establish there is a problem and you need to see the extent of that problem," says Peggy Pust, Director of Imaging Services at Monongalia General Hospital. "Certain cancers will occur in the other breast. Many times the doctors won't do the surgery until they are fully aware of all the cancer that is there."

Recent studies conducted by the National Cancer Institute (NCI) found that MRI was not only more effective than mammography, but also better than ultrasound or other clinical breast exams in finding breast cancer in women who had the screening.

The study showed that MRIs were accurate in detecting breast cancer in 83 percent of the 54 women who participated. The MRI returned a false positive in 17 percent of its diagnoses.

"You inject a contrast agent, and as it's going through the body, there's increased vascularity and the uptake of the solution is greater if a tumor is present. That shows up as a hotspot on an MRI, so you can make a more definitive diagnosis by looking at that," says Hall. "You certainly would not think about doing an MRI for every single situation. It's very expensive and not all that pleasant a procedure, and not required to do a basic screening. It's typically used as a second-step diagnostic tool. If you find something on the mammogram that looks suspicious, this gives you new avenues to explore it."

MRI has shown usefulness as a next-step imaging modality for difficult- to-diagnose cases, as well. Much like X-ray mammography, breast MRI relies on anatomical or structural information, but provides much more detailed images. It is limited, however, by its highly variable specificity, which can range from below 37% to 97%. Combined with its high sensitivity, MRI produces a high false positive rate. It also is sometimes difficult to schedule, and may require multiple days to complete.

The major disadvantage of breast MRI is the cost, which is about 15 times that of a basic mammogram. The entire exam could run anywhere from $1,000 to $1,500.

"If money was no object and time was no object, I guess MRI would be the answer," Schroeder says. "If you had an unlimited number of scanners and slots and people to read it, but that's not going to happen, it's not practical."

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