Mammogram is an X-ray that yields images of the breast to look for microcalcifications while a breast ultrasound is an imaging study that converts high speed sound waves into pictures to assess the tissues within the breasts. A mammogram is conducted by compression of each breast in turn between two flat plates for a few seconds whilst the X-ray is taken. A breast ultrasound uses a small hand-held probe to move across the breasts, and takes about 10 to 30 minutes to complete the imaging.
A breast ultrasound is useful to:
Evaluate the cause of breast abnormalities   Determine the nature of the breast lump (fluid or solid) Supplement other tests such as a mammogram or a breast MRI Aid the placement of needles for procedures such as a biopsy
Breast ultrasound cannot replace a mammogram in detecting microcalcifications useful in early breast cancer detection.