Magnetic Resonance, or MR, guided breast biopsy uses a powerful magnetic field, radio waves and a computer to help locate a breast lump or abnormality, and guide a needle to remove a tissue sample for examination under a microscope. It does not use ionizing radiation and leaves little to no scarring.

MR guided biopsy is most helpful when MR imaging best shows a breast abnormality such as a suspicious mass not identified by other imaging techniques, an area of distortion or an area of abnormal tissue change.

When would I get a MRI Breast Biopsy?

A breast biopsy is performed to remove some cells from a suspicious area in the breast and examine them under a microscope to determine a diagnosis. This can be performed surgically or, more commonly, by a radiologist using a less invasive procedure that involves a hollow needle and image guidance. Image-guided needle biopsy is not designed to remove the entire lesion.

MRI guided breast biopsy is warranted for BI-RADS (Breast Imaging Reporting and Data System) 4-5, which are findings reported on your screening mammogram. BI-RADS 4 means that the findings on your mammogram are suspicious and that there is approximately a 23% to 34% chance that this is breast cancer. BI-RADS 5 means that your mammogram results are highly suspicious with a 95% chance of breast cancer.

What Will I Experience?

A nurse or technologist will insert an intravenous (IV) line into a vein in your hand or arm and the contrast material gadolinium will be given intravenously.

Your breast will be gently compressed between two compression plates (similar to those used in a diagnostic MRI exam), one of which is marked with a grid structure. Using computer software, the radiologist measures the position of the lesion with respect to the grid and calculates the position and depth of the needle placement.

A local anesthetic will be injected into the breast to numb it. A very small nick is made in the skin at the site where the biopsy needle is to be inserted.

The radiologist then inserts the needle, advances it to the location of the abnormality and MR imaging is performed to verify its position. Tissue samples are then removed. After this sampling, the needle will be removed.

Once the biopsy is complete, pressure will be applied to stop any bleeding and the opening in the skin is covered with a dressing. No sutures are needed.

This procedure is usually completed within 45 minutes.