Before the Procedure

There is very little preparation required for a Breast MRI. The timing of the study should be closely linked to the menstrual cycle for women who are premenopausal. The best time to perform a Breast MRI is between days 6 and 14 of your menstrual cycle (day one is the day that your period arrives). For patients who are postmenopausal, or those with a new diagnosis of breast cancer, the examination can be performed at any time. For those who are perimenopausal, it is optimal to wait for the next cycle to start, and schedule between days 6 and 14. If the menses occur only rarely, then the examination can be scheduled at any time with the understanding that residual hormonal activity can render the examination difficult to interpret.

The MRI Technologist will explain the procedure to you and offer the opportunity to ask any questions that you might have about the procedure.

If your procedure involves the use of contrast, you will be asked to sign a consent form that gives permission to do the procedure. Read the form carefully and ask questions if something is not clear.

Personal items, such as your watch, wallet, including any credit cards with a magnetic strip (which may be erased by the magnet), will be left in a secure locker prior to the MRI scan.

Before the examination, it is extremely important that you inform the MRI technologist if any of the following apply to you:

  • You are claustrophobic and think you will be unable to lie still while inside the scanning machine, in which case you may be given a sedative.
  • You have a pacemaker or have had heart valves replaced.
  • You have any type of implantable pump, such as an insulin pump.
  • You have metal plates, pins, metal implants, surgical staples, or aneurysm clips.
  • You have metallic fragments anywhere in the body.
  • You have permanent eye liner or tattoos.
  • You are pregnant or suspect you may be pregnant.
  • You ever had a bullet wound.
  • You have ever worked with metal (for example, a metal grinder or welder).
  • You have any body piercing.
  • You are wearing a medication patch.
  • You are not able to lie down for 30 to 60 minutes.

As there is a possibility that you may receive a sedative before the procedure, you should plan to have someone drive you home afterwards.

During the Procedure

Generally, a breast MRI follows this process:

  • You will be asked to remove any clothing, jewelry, eyeglasses, hearing aids, hairpins, removable dental work, or other objects that may interfere with the procedure.
  • You will be given a hospital gown to wear.
  • If you are to have a procedure done with contrast, an intravenous (IV) line will be started in the hand or arm for injection of the contrast.
  • You will be positioned, face down on a mobile bed, with your breasts positioned through cushioned openings. The bed will then be moved into the magnet of the MRI machine. Pillows or straps may be used to prevent movement during the procedure.
  • The MRI technologist will be in a separate room inside the larger MRI room where the scanner controls are located. Speakers inside the scanner will enable the technologist to communicate with and hear you. You will have a call button so that you can let the technologist know if you have any problems during the procedure. The MRI technologist will be watching you at all times and will be in constant communication.
  • You will be given earplugs or a headset to wear to help block out the noise from the scanner. Some headsets may provide music for you to listen to.
  • During the scanning process, a loud clicking noise will sound as the magnetic field is created and pulses of radio waves are sent from the scanner.
  • It will be important for you to remain very still during the examination, as any movement could cause distortion and affect the quality of the scan.
  • At intervals, you may be instructed to hold your breath for a few seconds, depending on the views of the breasts being examined.
  • If contrast is used for your procedure, you may feel some effects when the dye is injected into the IV line. These effects include a flushing sensation or a feeling of coldness, a salty or metallic taste in the mouth, a brief headache, itching, or nausea and/or vomiting. These effects usually only last for a few moments.
  • Your breasts may feel slightly warm, but this is normal.
  • You should notify the technologist if you have any breathing difficulties, sweating, numbness, or heart palpitations.
  • Once the scan has been completed, the table will slide out of the scanner and you will be assisted off the table.
  • If an IV was inserted for contrast administration, it will be removed.

While the MRI procedure itself causes no pain, having to lie still for the length of the procedure might cause some discomfort or pain, particularly in the case of a recent injury or invasive procedure such as surgery. The technologist will use all possible comfort measures and complete the procedure as quickly as possible to minimize any discomfort or pain.

After the Procedure


You should move slowly when getting up from the scanner table to avoid any dizziness or light-headedness from lying prone for the length of the procedure.

If any sedatives were taken for the procedure, you may be required to rest until the sedatives have worn off. You will also need to avoid driving.

If contrast was used during your procedure, you may be monitored for a period of time for any side effects or reactions to the contrast, such as itching, swelling, rash, or difficulty breathing.

If you notice any pain, redness, and/or swelling at the IV site after you return home following your procedure, you should notify your health care provider, as this could indicate an infection or other type of reaction.

Nursing mothers may choose not to breastfeed for 12 to 24 hours after a breast MRI with contrast.

Generally, there is no special type of care required after a MRI scan of the breasts. You may resume your usual diet and activities, unless your health care provider advises you differently.

A radiologist will analyze the images and provide a report to your health care provider within 10 business days.

Your health care provider may give you additional or alternate instructions after the procedure, depending on your particular situation.

Breast MRI Results


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.

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