Preparing for a breast MRI
No special preparation is required. You can eat and drink as you normally would, engage in regular activities, and take any prescription medication.
Plan to arrive about 30 minutes before your appointment time.
What to expect
You will be asked to change into a gown because belts, zippers, snaps, and thread in clothing may contain metal that disrupts the MRI signals.
We will ask you questions before you enter the MRI exam room to confirm that you don’t have any metal in or on your body. You need to remove all metallic objects such as jewelry, glasses, hairpins, hearing aids, and dentures. (Personal belongings can be locked in a dressing room.) Please tell the technologist if you have metal implants, a cardiac pacemaker, permanent dental bridges, braces, or other metal objects in your body.
During the exam, you will lie on your stomach with your breasts placed in openings in the examination table so that they are suspended away from your chest. Unlike conventional x-ray mammography, breast MRI does not require your breasts to be compressed, so you should not experience that discomfort. You will enter the machine head first, which reduces feelings of claustrophobia sometimes associated with full-body MRI scanners.
You will receive an injection (usually in the arm) of a contrast agent called gadolinium. This helps to highlight various structures in breast tissue. The gadolinium is given through a small intravenous catheter, which is placed in the arm by a certified technologist.
An initial scan will be taken and then repeated after the gadolinium is given. For best results, you should lie very still, relax, and breathe normally. The technologist can see and hear you at all times. The entire exam takes about one hour.
After the exam
There are no side or after effects with MRI, so you can resume your normal activities as soon as your exam is over. The radiologist will interpret your MRI scan and report the findings to your doctor.
Implants and MRI
Breast MRI is sometimes used to image silicone breast implants. If you have breast implants, it is important that you tell the technologist when they call you before your exam. We will also need to know if your implants are filled with saline, silicone, oil, or a combination of these. In addition, we need to know if the implant has a polyvinyl chloride sponge covering. Please get this information from your plastic surgeon’s office prior to your MRI exam.
Biopsies and wire localizations
MRI detects lesions that cannot be seen through ultrasound or mammography, so it is critical to localize or biopsy these lesions using that same technique. If a suspicious area is detected, your physician may recommend an MRI-guided breast biopsy. This type of biopsy may be a preferred alternative to a surgical biopsy. MRI-guided biopsy requires only a topical anesthetic, leaves little to no scarring, and can be performed in less than an hour.
What breast MRI may find
Lesion characterization: Breast MRI may be indicated when other imaging examinations, such as ultrasound and mammography, and physical examination are inconclusive for the presence of breast cancer. Other conditions that may impair conventional breast imaging, such as silicone augmentation or radiographically dense breasts, may warrant breast MRI depending on the clinical findings.
Opposite breast examination in patients with breast malignancy: MRI can detect unsuspected disease in the opposite breast in at least 4-5% of breast cancer patients. This is often in the face of negative findings on mammography and physical examination.
Scar versus tumor: Breast MRI may be helpful in patients who have had previous surgery for breast cancer to distinguish between post-operative scarring and recurrent cancer.
Axillary adenopathy, primary unknown: MRI may be indicated in patients presenting with axillary adenopathy and no mammographic or physical findings of primary breast carcinoma. In patients with breast cancer, breast MRI can locate the primary tumor and define the disease extent for definitive therapy. A negative breast MRI may exclude the breast as a potential primary site of cancer and avoid a mastectomy that would provide no treatment benefit.
Recurrence of breast cancer: Breast MRI may be indicated in women with a prior history of breast cancer and suspicion of recurrence when clinical and/or mammographic findings are inconclusive.
Silicone and non-silicone breast augmentation: Breast MRI is useful in the evaluation of patients with silicone implants and/or injections in whom mammography is difficult and in patients with non-silicone implants. In these settings, breast MRI may be helpful in the diagnosis of breast cancer and in the evaluation of implant integrity and rupture.
When breast MRI is NOT recommended
MRI is not recommended for certain situations. These situations may include, but are not limited to, the presence of cardiac pacemakers; ferromagnetic intracranial aneurysm clips; certain neurostimulators; certain cochlear implants; and certain other ferromagnetic implants, devices, foreign bodies, or electronic devices.
It is recommended that breast MRI scans be performed during the second menstrual week whenever possible. Imaging both breasts during this time may enhance conditions such as fibrocystic changes, which often occur in both breasts.