Breast Imaging: Beyond Traditional Mammograms

Wednesday, April 26, 2006

ROCHESTER, Minn. — Mammography has been and remains the gold standard in early detection of breast cancer. Mammograms are X-rays of the breasts to look for suspicious masses or breast tissue changes before they can be seen or felt.

But mammography is not perfect. Accuracy depends on the quality of film, the technique used and the skill of the radiologist examining the films. Dense breast tissue can make abnormalities difficult to see on a mammogram.

The May issue of Mayo Clinic Women's HealthSource examines other imaging technology in use or that's being studied to help doctors detect and diagnose breast cancer.

Digital mammography: Like film mammography, digital mammography uses X-rays to produce an image of your breast. Digital images, recorded in a computer, can be enhanced by the radiologist. For example, the radiologist can zoom in on an area, making it easier to identify changes in breast tissue.

The technology is still new and expensive; only a few facilities offer it for screening. Results comparing film and digital mammography have so far shown no difference in detecting cancer for most women. However, at least one major study found that women under 50 who have dense breast tissue may benefit from having a digital rather than a film mammogram.

Ultrasound: Ultrasound is a procedure that uses high-frequency sound waves to display images of the inside of your body on a computer screen. It is used to determine if a lump or suspicious area is a cyst or solid mass. Cysts (sacs of fluid) aren't cancerous, but a solid mass may be.

Research suggests that ultrasound may be useful in screening women with dense breast tissue. It can also be useful in evaluating masses in women with breast implants, because the technology can distinguish breast tissue from implant materials.

Ultrasound is not a substitute for mammography because it doesn't reliably detect small calcium deposits in the breast, which can be an early sign of breast cancer.

Magnetic resonance imaging (MRI): This technique uses a magnet linked to a computer to create detailed pictures of areas inside your body — without using radiation. MRI can produce hundreds of images of your breast. It's used to assess abnormal areas that are seen on a mammogram. Studies have found that MRI can be a valuable screening tool for young women with dense breast tissue who are at high risk of breast cancer.

MRI isn't recommended for routine screening because it's expensive, not readily available and has a high rate of false-positives, indicating cancer is present when it's not.

Molecular breast imaging (MBI): This technique tracks the movement of a short-lived radioactive agent that's injected into your arm. Tumors tend to absorb more of the agent than does healthy tissue. Several techniques are being studied and so far are only available to women participating in clinical trials. Researchers believe MBI ultimately may aid in detecting breast cancer, especially in women with dense breast tissue.

For most women, mammography remains the main breast-imaging test. For some women, other imaging techniques may offer advantages when added to mammography in breast cancer screening and diagnosis.
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