MRI Facts

Breast Magnet Resonance Imaging (MRI) is an examination that is used to detect abnormalities in the breast. It does not replace mammography but rather is used in clinical situations where additional information is needed.

Breast MRI uses magnetic fields to generate detailed images of the breast which are generated by a computer and reviewed on a computer by the radiologist. Breast MRI is a technology that allows for additional evaluation of the breast and may have information that is not seen with mammography or ultrasound. A breast MRI examination often generates several thousand images that must be reviewed by the radiologist.

Preparation for the examination:
You should wear loose clothing and other preparation varies from place to place, i.e. with regard to eating and drinking prior to the examination.

Breast MRI is performed in a machine that is like a cylinder and requires an injection of a contrast agent to be able to optimally see the characteristics of the breast which would allow for the detection of breast cancer.

During the examination you will lie face down on a table and your breasts will loosely hang in a cushioned opening surrounded by the equipment.You will not feel anything on your body during the examination but the imaging will have loud sounds and you will be moved in and out of the machine during the examination which should take about 1 hour. Often, an MRI examination requires injection of a contrast agent, which does not contain iodine, but which will require an IV to be started and the contrast will be injected during the examination. 

Throughout the examination you will be in constant communication with the technologist so if anything bothers you, you should let them know so they can make it better.

Breast MRI CANNOT be performed in an open MRI since the strength of the equipment will not allow for adequate visualization of the tissues and although some places may tell you that the open magnetic is adequate to image the breasts, it is not!!

• MRI does not replace mammography but rather has additional information that may be used in:
• Women with newly diagnosed breast cancer
• Women at very high risk for breast cancer for whom additional surveillance is indicated
• Women with an equivocal mammographic or clinical finding that requires more information to determine if what they have is significant
• in certain other situations as determined by your physician.

 Certain women cannot undergo an MRI:

• Patients with pacemakers
• Some Patients that may be physically uncomfortable or incapable of being in a MRI
• Patients with some limitation of kidney function (if contrast is to be used). If you are over the age of 50, your kidney function should be tested prior to undergoing the examination and will likely be checked by MRI staff immediately prior to the examination
• Some claustrophobic patients.

Although MRI is an exciting new tool for breast cancer detection there are limitations. Firstly, some women who might need the information from MRI may not be able to undergo the examination. 

Additionally, it is important to realize that there are false positive findings with MRI. That is, an abnormal area may show up on the examination that is not cancer. This is particularly true in pre-menopausal women or women taking Hormone Replacement Therapy. 

If you are pre-menopausal and at high risk for breast cancer and are advised to undergo an MRI to check for cancer, you should have the examination on day 7-14 of your menstrual cycle to minimize the likelihood of false positive findings.