Mammograms and Other Breast Imaging Tests

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What’s the difference between a screening mammogram and a diagnostic mammogram?

Screening mammograms look for signs of cancer

Screening mammograms are x-ray exams of the breasts that are used for women who have no breast symptoms or signs of breast cancer (such as a previous abnormal mammogram). The goal of a screening mammogram is to find breast cancer when it’s too small to be felt by a woman or her doctor. Finding breast cancers early (before they have grown and spread) greatly improves a woman’s chance for successful treatment.

A screening mammogram usually takes 2 x-ray pictures (views) of each breast. Some women, such as those with large breasts, may need to have more pictures to see as much breast tissue as possible.

Diagnostic mammograms investigate possible problems

A woman with a breast problem (for instance, a lump or nipple discharge) or an abnormal area found in a screening mammogram typically gets a diagnostic mammogram. Sometimes diagnostic mammograms are done for screening in women without breast problems who were previously treated for breast cancer.

During a diagnostic mammogram, the images are reviewed by the radiologist while you are there so that more pictures can be taken if needed to look more closely at an area of concern. In some cases, special images known as spot views or magnification views are used to make a small area of concern easier to evaluate. Other types of imaging tests such as ultrasound may also be done in addition to the mammogram, depending on the type of problem and where it is in the breast.

A diagnostic mammogram is usually interpreted in one of three ways:

  • It may reveal that an area that looked abnormal on a screening mammogram is actually normal. When this happens, the woman goes back to routine yearly screening.
  • It could show that an area of concern probably is not cancer, but the radiologist may want to watch the area closely. When this happens it’s common to ask the woman to return to be re-checked, usually in 4 to 6 months.
  • The results could also suggest that a biopsy is needed to find out if the abnormal area is cancer. If your doctor recommends a biopsy, it does not mean that you have cancer.

For help with understanding your mammogram report and your radiologist’s estimate of your cancer risk, see the section “Understanding your mammogram report – BI-RADS categories.” If a biopsy is needed, you should discuss the different types of biopsy with your doctor to decide which type is best for you. To learn more about them, please see our document For Women Facing a Breast Biopsy.


Last Medical Review: 12/08/2014
Last Revised: 12/08/2014