Digital Mammography and Breast MRI: What's Newer and Better Out There?

The MRI (magnetic resonance imaging) is technology that’s been in use for years, but only recently has become a player in breast-cancer screening. It uses a magnet and radio waves to create 3-D cross-section images of your breasts; an injection of a contrast agent prior to the exam helps highlight any areas of abnormality. Well, that sounds pretty cutting-edge, you think. But hold on. Breast MRIs, thus far, have proven better than mammograms in only one way: clarifying abnormalities picked up on a regular film or digital mammogram. They’re not yet approved by the FDA as a general-population breast cancer screening tool (though they are recommended for young women whose genetics place them at high risk for cancer, as MRIs are particularly accurate detecting tumors in dense breasts, and younger women generally have denser breasts).

MRIs are a bigger deal than mammograms, too, in all ways; they’re up to 10 times as expensive, they take up to 10 times as long (including the injection), and they can be quite uncomfortable, if you’re prone to claustrophobia. Bottom line: useful if a problem is discovered or suspected, but as an adjunct to, not a replacement for, the standard mammogram.

Finally, you may have heard of CAD: computer-aided detection. CAD is simply software that scans a digital mammogram, highlighting potential problem areas that your radiologist might not have been able to see. Its main benefit is its accuracy: it’s been found to detect approximately 20% more cancers than were detected by a radiologist’s reading alone. It’s also reasonably priced; it adds just $10 to $15 to the cost of your mammogram. However, it works only with digital (not film) mammograms; some hospitals choose to scan and digitize film in order to use CAD along with their film mammography units. Plus, the cost of implementing the CAD system is high, so most hospitals have yet to adopt it. Again, bottom line: useful as an add-on, but not a replacement for mammography.

So, where do we stand, among all this technology? “The big squeeze”–the standard mammogram, whether digital or film–is still the diagnostic tool of choice for breast cancer detection. CAD software can double-check the radiologist’s reading, and an MRI can clarify suspected problems, but for now, the mammogram is still your weapon of choice for early breast cancer detection.