What to Expect with a Breast MRI

Christina Bates -

A breast MRI (magnetic resonance imaging is a noninvasive test that uses a magnetic field, radio waves and a computer to produce detailed images that can reveal lesions not detectable with mammography or ultrasound.

For the test, a nonradioactive contrast agent (dye) must be injected into the bloodstream. Since cancerous areas have more blood vessels, more dye goes to those areas, making the resulting MRI images clearer.

A breast MRI may be prescribed if you…

  • Are at high risk because of a family history of breast cancer or because genetic testing revealed that you carry a breast cancer gene.
  • Have a mammogram with inconclusive results that merit clarification.
  • Are undergoing chemotherapy for breast cancer, since MRI can reveal whether the disease is responding to treatment.
  • Were recently diagnosed with breast cancer—because MRI may be useful for presurgical planning. In one recent study from the University of Rome involving 164 breast cancer patients, MRI detected 51 additional suspicious lesions not seen on other tests...and changed the proposed treatment for 20% of patients. In a second study from the same researchers, presurgical MRI was associated with a reduced risk for cancer recurrence. According to radiologist Rachel F. Brem, MD, director of the Breast Imaging and Intervention Center at The George Washington University (GWU) Medical Center, all GWU patients with newly diagnosed breast cancer have an MRI or other imaging test, though this is not the standard at all breast centers.

Risks: The MRI scan itself poses no danger. Possible side effects of the contrast agent include headache, nausea, chest pain, skin rash and irregular heartbeat. Your doctor can help you weigh the test's benefits against these risks.

MRI may not be safe or appropriate if you…

  • Have an implanted device (pacemaker, cerebral aneurysm clip, cochlear implant, plate, screw or rod) made of any metal other than titanium anywhere in your body. Because MRI uses a powerful magnet, a non-titanium metal device could shift position during the test.
  • Are pregnant or breast-feeding the contrast agent could be toxic to the baby).
  • Have kidney problems. Since patients with kidney disease eliminate the contrast agent from their bodies more slowly, they are at increased risk for side effects, including a serious condition that involves thickening of the skin and organ damage.

Note: Before undergoing a breast MRI, women age 50-plus routinely have a blood test to check for kidney problems.

  • Weigh 300 pounds or more—you might have trouble fitting comfortably inside the MRI apparatus.

Where And When To Schedule Your MRI

Ask your doctor to refer you to an imaging facility that handles a large volume of breast MRIS, so the staff will have extensive experience with the test. GWU, for instance, does four to six breast MRIs daily, Dr. Brem said.

If you are having an MRI for screening purposes only and you are postmenopausal, simply schedule your MRI at your convenience. If you are premenopausal, the ideal time to have your MRI is between day seven and day 14 of your menstrual cycle (with day one being the first day of your period). Because this is when breasts are least affected by your natural hormones, the MRI results will be easiest to interpret. If you have an irregular cycle, just wait until you get your period and then schedule your MRI for day seven to 14.

Exception: If you have breast cancer or an inconclusive mammogram, do not wait for that day-seven-to-14 window-schedule your MRI immediately, Dr. Brem advised.

What Happens On The Day Of The Test

You remove any metal you are wearing (jewelry, hairpins, eyeglasses), and an intravenous (IV) line is placed in your arm to deliver the contrast agent. You lie face-down on a padded table, face nestled into a donut-shaped pillow and breasts hanging freely into cushioned openings containing a signal receiver. Make sure you're really comfortable because you must remain motionless once the test begins. Then you are slid into the MRI tube, which encircles your entire body.

Do you get claustrophobic? Tell your physician ahead of time so he or she can prescribe a calming medication if necessary. To relax inside the tube, focus on your breathing (but don't take deep belly breaths, since staying still is paramount) or imagine yourself in a pleasant place (a mountaintop, a beach). Many imaging centers provide headphones so patients can listen to music, which camouflages the MRI machine's knocking and buzzing noises. The technician can see you and speak to you, and if you need to get out, you can signal the technician by squeezing a handheld device. (Test the signaling device before entering the MRI to make sure it works.)

After some initial images are taken the dye is injected into your bloodstream via the IV. You may feel a spreading sensation of warmth and/ or notice a metallic taste in your mouth. Expect to be in the tube for about 30 minutes as the MRI produces more than 3,000 images, each showing a thin slice of your breasts.

With so many images to interpret, it may take a few days to get your results. At that point, you and your doctor can discuss the appropriate next steps to take to safeguard your health.

Hot Flashes? Night Sweats? It Could Be Good!

According to a recent study, women who experience intense hot flashes that wake them up at night and other severe symptoms of menopause, such as night sweats, vaginal dryness, bladder problems and depression, have up to 50% lower risk for breast cancer than women who don't have such symptoms. The protective effect increases with the number and severity of menopausal symptoms.

Possible reason: The symptoms occur as hormone levels fluctuate and drop. Women who have the intense symptoms may have lower levels of estrogen. High levels of estrogen are linked to breast cancer.

Better Breast Cancer Drug

Postmenopausal women with breast cancer do better with the drug letrozole (Femara) than tamoxifen.

Recent study: Women who had early-stage breast cancer who took letrozole were 21% less likely to die than women who took tamoxifen during the eight-year follow-up period, which included five years of treatment.