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UW Health SMPH
American Family Children's Hospital

Magnetic Resonance Imaging (MRI)-guided Needle Core Biopsy

UW Health's radiology services in Madison, Wisconsin offer a wide variety of breast imaging services, including magnetic resonance imaging (MRI)-guided needle core biopsy.


When Magnetic Resonance Imaging (MRI)-guided Needle Core Biopsy is Used


Magnetic resonance imaging (MRI)-guided needle core biopsy may be performed using a specialized biopsy device when a breast abnormality requiring biopsy is detected only by MRI. The biopsy device quickly obtains a small core of tissue. The procedure is generally painless and leaves no surgical scar.
Research has shown that MRI–guided needle core breast biopsy is as accurate as surgical excisional breast biopsy. In rare cases, however, the procedure may need to be repeated or surgical excisional breast biopsy may need to be performed in order to sample a larger area of tissue. Although rarely needed, these additional procedures are performed to be absolutely certain the abnormality is not cancer.


The Procedure


At the time of your exam, the technologist will position you on the exam table of the scanner and, after placing a small intravenous catheter, the table will move into the tube-like scanner. You breast will be lightly compressed by a plate that contains a grid for locating where the biopsy needle will be inserted.
During the imaging, you will hear dull pounding and clicking sounds coming from the scanner. This is normal. If it bothers you, tell the technologist and you will be provided with earplugs.


An initial set of images will be obtained after the injection of a small amount of contrast agent through your IV. During the examination, it is critical that you remain very still. The technologist will tell you when it is all right to move.


When the abnormality is located on the images, you will be removed from the scanner but you will remain in position on the exam table. After cleansing, the skin is numbed with a local anesthetic, and a small skin incision is made in order to introduce the biopsy guide into the breast. The biopsy guide is then directed to the abnormality.


You will be moved into the scanner again for a second set of images to check the position of the biopsy needle guide. If the biopsy needle guide is in good position, you will be removed from the scanner and the biopsy device will be inserted through the guide.


As the biopsy device is activated, a "click or humming noise" is heard and the tissue along the path of the needle is removed. Several small tissue samples are obtained from the abnormality and are sent to the pathologist for examination under a microscope. A tiny marker will be placed to mark the biopsy site.


You will be moved into the scanner for the final set of images to check the biopsy site and marker. If the biopsy site and marker are in good position, you will be removed from the scanner and may sit up from the exam table.


We hold pressure on the biopsy site for a few minutes, then a small dressing is applied. You will be escorted to the Breast Center for a post-procedure mammogram.


After the Procedure

The procedure may produce minimal discomfort and bruising. A non–aspirin product is typically sufficient for any discomfort. Strenuous activity is discouraged for 24 hours.


Your referring physician should receive the results of your biopsy within one week. Please contact their office for your final results. Many breast abnormalities prove to be benign (non–cancerous) by the pathologist and need no further treatment. The radiologist and your physician may chose to follow these benign abnormalities in three to six months to ensure they do not change.