Ultrasound uses sound waves rather than x-rays to produce images of the tissues inside the breast. A breast ultrasound can show all areas of the breast, including areas harder to study with a mammogram.
A breast ultrasound is often used to see whether a breast lump is filled with fluid (a cyst) or is a solid lump.
An ultrasound does not replace the need for a mammogram, but it is often used in conjunction with mammograms to further analyse areas of interest demonstrated on a mammogram.
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