The health and safety of our clients, staff and community is our top priority. Click here for more information.
The health and safety of our clients, staff and community is our top priority. Click here for more information.
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enImaging appointments available weekdays and evenings. Call us to book your appointment.
enImaging appointments available weekdays and evenings. Call us to book your appointment.

Breast MRI FAQ

What is breast MRI?

MRI stands for Magnetic Resonance Imaging. MRI is a non-invasive way to image the breasts. Unlike mammography, MRI does not use any radiation. Instead, MRI uses a powerful magnetic field, radiofrequency pulses and a computer to produce images of the breast. MRI provides a 10 to 100 times greater contrast between breast tissues than an X-ray, enabling the radiologist to see the inside breast tissue side-to-side, front-to back, and top-to-bottom.

Who should have a breast MRI screening?

Yearly mammograms plus breast MRI screening are typically recommended for women who are at higher-than-average risk of developing breast cancer. Women at high risk have a greater estimated risk of developing breast cancer (up to 85%) than the general population (10 to 12%).

Women at high risk develop breast cancer at an earlier age and their breast cancers tend to be more aggressive than breast cancers diagnosed in women of average risk.

The American Cancer Society (ACS) recommends that all high-risk women — those with a greater than 20% lifetime risk of breast cancer — have a breast MRI and a mammogram every year. For most women, these combined screenings should start at age 30 and continue as long as the woman is in good health. According to ACS guidelines, high-risk women include those who:

  • Have a known BRCA1 or BRCA2 gene mutation.
  • Have a first-degree relative (mother, father, brother, sister, or child) with a BRCA1 or BRCA2 gene mutation and have not had genetic testing themselves.
  • Find out they have a lifetime risk of breast cancer of 20% or greater, according to risk assessment tools that are based mainly on family history.
  • Had radiation therapy to the chest for another type of cancer, such as Hodgkin’s disease, when they were between the ages of 10 and 30 years.
  • Have a genetic disease such as Li-Fraumeni syndrome, Cowden syndrome, or Bannayan-Riley-Ruvalcaba syndrome, or have one of these syndromes in first-degree relatives.

The American Cancer Society also recommends that women at moderately increased risk of breast cancer — those with a 15-20% lifetime risk — consider the possibility of adding breast MRI screening to their yearly mammogram. According to ACS guidelines, this includes women who:

  • Find out they have a lifetime risk of breast cancer of 15-20%, according to risk assessment tools based mainly on family history.
  • Have a personal history of breast cancer, ductal carcinoma in situ (DCIS), lobular carcinoma in situ (LCIS), or abnormal breast cell changes such as atypical ductal hyperplasia or atypical lobular hyperplasia.
  • Have extremely dense breasts or unevenly dense breasts when viewed by mammograms.

Other common uses for Breast MRI

  • Further evaluation of abnormalities detected by mammography.
  • Examination for cancer in women who have implants or scar tissue that might produce an inaccurate result from a mammogram. This test can also be helpful for women with lumpectomy scars to check for any changes.
  • Detecting small abnormalities not seen with mammography or ultrasound (for example, MRI has been useful for women who have breast cancer cells present in an underarm lymph node, but do not have a lump that can be felt or can be viewed on diagnostic studies). 
  • Assess for leakage, collapse, or other problems associated with silicone gel or saline implants.
  • Evaluate the size and precise location of breast cancer lesions, including the possibility that more than one area of the breast may be involved (this is helpful for cancers that spread and involve more than one area).
  • Detecting changes in the other breast that has not been newly diagnosed with breast cancer (There is an approximately 10 percent chance that women with breast cancer will develop cancer in the opposite breast. A recent study indicates that breast MRI can detect cancer in the opposite breast that may be missed at the time of the first breast cancer diagnosis.).
  • Detection of the spread of breast cancer into the chest wall, which may change treatment options.
  • Determining whether lumpectomy or mastectomy would be more effective.
  • Detection of breast cancer recurrence or residual tumor after lumpectomy
  • Evaluation of a newly inverted nipple change


How do I prepare for the exam?

In most cases, you can just stick with your normal, everyday routine – no special preparation is needed. You can eat and drink your usual diet, work, or play sports, and take any prescription medications you need. However, there may be some circumstances in which you’ll be given specific instructions to follow before the exam. These will be given to you by your doctor, or by our clinic staff at the time the MRI is scheduled.

When you arrive for your exam, you will be asked to change into scrubs that we will provide for your comfort and convenience during the examination.

How long does a breast MRI take?

A typical breast MRI includes about 25 to 30 minutes of scan time. Total time from intake to completion is about an hour.

Will the breast MRI hurt?

We make every effort to make you comfortable for your breast MRI. The test itself should not cause any pain, although some people do find it uncomfortable to lie on their stomachs.

How will I be positioned for my breast MRI?

You will lie on your stomach with your arms at your sides on a padded table. Your breasts will hang in a natural position through two openings in the breast coil, which acts like an antenna. An adjustable headrest and padding under your ankles help to make you more comfortable.

What is it like inside the machine?

The MRI machine is quite loud. You will be given headphones to help block out the noise. This will also allow the technologist to communicate with you. Some patients note that they feel warm in the area being scanned.

Do I have to get an injection?

Yes. It is necessary to inject an MRI contrast material (called gadolinium) in order to highlight abnormal tissues such as breast cancers.

Can I have an MRI instead of a mammogram?

No. Breast MRI is meant to be used in conjunction with mammography, not in place of it. Mammography detects some cancers that MRI may miss.

What are the benefits to breast MRI?

There is no radiation involved. Breast MRI has been shown to help detect small breast cancers that may be missed by mammography or ultrasound. MRI can successfully image dense breasts common in younger women.

Are there any contraindications to breast MRI?

Yes. As with any MRI, certain health conditions may preclude you from having an MRI. These include the presence of a pacemaker or defibrillator, inner ear implants, metal fragments in the eyes, or women who are pregnant or breastfeeding. You will be asked these and other screening questions on the phone prior to your MRI and again when you arrive for your test.

Will I have any side-effects from the MRI?

No. After the MRI you may resume your normal activities.

How accurate is breast MRI?

Breast MRI is very sensitive for most cancers, with some exceptions, such as low-grade DCIS. Some benign conditions such as fibrocystic disease can look like cancer. Hormones can also affect the results of the test. This is why we ask questions about menstrual cycle and hormone therapies prior to your study.

I’ve already been diagnosed with breast cancer. Why would I need a breast MRI?

You would need a breast MRI in order to:

  • Get additional information on a diseased breast to make treatment decisions
  • Determine whether the cancer has spread further in the breast or into the chest wall
  • Assess multiple tumor locations, especially prior to breast conservation surgery and/or partial breast irradiation
  • Assess the opposite breast for tumors
  • Assess how well chemotherapy is working
  • Distinguish between scar tissue and recurrent tumors


How do I know if I am a good candidate for a breast MRI?

Your physician can make the best determination regarding your need for a breast MRI. However, usually patients will fall into these categories:

  • Patients with recently diagnosed breast cancer for pre-op planning
  • Presence of a breast cancer mutation or untested first-degree relatives of proven BRCA carriers
  • Malignant axillary lymph nodes with unknown primary
  • Received radiation to the chest between ages 10 and 30
  • Lifetime risk of breast cancer scored at 20% or greater
  • If you are having a screening MRI, it is crucial that you are scanned between days 7-14 of your menstrual cycle if you are pre-menopausal.


How will I get the results of my breast MRI?

Your MRI will be read locally by a select group of board-certified radiologists. These physicians have extensive experience and training in breast imaging and intervention. Within 10 business days, the findings will be sent to your physician, who will communicate the results to you.

What is the likelihood of “false positive” results with a breast MRI?

Due to the increased sensitivity of the MRI, there is a likelihood of increased “false positive” results. The “false positive” rate on an initial MRI can be as high as 15%, but may be only 5-8% if a prior MRI is available for comparison.

Sometimes a benign (non-cancerous) area of tissue in the breast can show up as a ‘bright spot’ on the MR images. Most often, the Radiologist can tell by the appearance of the tissue whether or not it is cancer. When this is not possible, further testing may be necessary. This may include a targeted mammogram or ultrasound of the spot, a follow-up MRI in 6-12 months, or perhaps a needle biopsy. Moncton MRI is not equipped to perform breast biopsies, so if required, a biopsy will need to be carried out at a hospital. If the biopsy needs to be performed with MRI guidance, this procedure is only performed at the Saint John Regional Hospital, The Chalmers Hospital in Fredericton and the Dumont Hospital in Moncton. Moncton MRI will facilitate any necessary follow-up in conjunction with your family doctor.

What is BIRADS?

BIRADS, or Breast Imaging-Reporting and Data System, is a widely accepted risk assessment and quality assurance tool in mammography, ultrasound or MRI. The system was developed to standardize reporting, and make reports more comprehensible to the non-radiologist reading the report.

The result of your breast MRI will fall into one of the following categories:

BIRADS 0 – Incomplete: Further imaging or information is required i.e. special mammographic views (compression, magnification), ultrasound. This is also used when requesting previous images not available at the time of reading.

BIRADS I – Negative: Symmetrical and no masses, architectural disturbances or suspicious enhancement present.

BIRADS II – Benign Findings: Interpreter may wish to describe a benign-appearing finding. These all should have characteristic appearances, and may be labeled with confidence; the interpreter might wish to describe intra-mammary lymph nodes, implants, etc. while still concluding that there is no evidence suggesting malignancy

BIRADS III – Probably Benign: Short interval (6 months) follow-up suggested. The accent is on the word benign.

BIRADS IV – Suspicious Abnormality:

  • There is a mammographic appearance which is suspicious for malignancy
  • Biopsy should be considered for such a lesion.

BIRADS V – An imaging appearance which is highly suggestive of malignancy: action should be taken.