Breast magnetic resonance imaging (MRI)

What is an MRI of the breast?

Magnetic resonance imaging (MRI) is a non-invasive medical imaging test with no radiation (no X-rays). By using a magnetic field, radio frequency pulses, and a computer, it produces detailed pictures of the breasts.

When is breast MRI used?

MRI of the breast is used for a number of reasons. It is not a replacement for mammograms (breast X-rays) or ultrasound, but is used to provide extra information about your breasts.

Some of the indications include:

• To further investigate abnormalities detected by mammograms and ultrasound.
• To assess the extent of a diagnosed cancer prior to planning treatment.
• To measure the effect of chemotherapy on breast cancers.
• To screen for cancers in women considered by Genetics to be high risk for developing a breast cancer.
• To check the condition of breast implants.

Essential information

Because of the powerful magnets used in MRI scanning, it is not a suitable test for everyone. Before the MRI the radiographer will go through a safety checklist with you.

It is very important that you tell us if you have:

• ever had an injury to your eye involving a metal object/fragment.
• ever been injured by a metallic object eg shrapnel.
• any form of surgical implant e.g. aneurysm clip, shunt (spinal or intraventricular), neurostimulation system, implanted pain control device, metallic stent, filter or coil.
• Cardiac (heart) pacemaker and/or internal cardiac defibrillator.
• artificial heart valves or coronary stents
• cochlear or other ear implants.
• non-limb prosthesis e.g. eye.
• insulin or other drug infusion pump.
• any other form of electronic or magnetically-activated implant, internal electrodes or wires.
• gastric or intestinal devices including feeding tubes, gastric bands or bypass, polyp clips or recent capsule endoscopy procedure.
• Breast tissue expander or implants
• Have had an operation in the last 6 weeks
• Vascular access port and/or catheter
• Tattoos
• Permanent or semi-permanent make-up

If any of the above applies to you we may have to defer your MRI until we can get more information about your medical history, but this is for your safety.

Marker clips are often used in breast imaging to mark an area in the breast at the time of a biopsy. If you have one of these clips in your breast please tell us, but it is unlikely to prevent you from having your MRI.

Premenopausal Women

Breast MRI in screening is optimal between days 6 – 13 of the menstrual cycle. We will try and schedule your examination at this time.

What happens when I arrive?

• You will be met by the MRI radiographer, who will check your personal details and go through a safety checklist with you.
• The radiographer will explain the procedure to you. Please feel free to ask any questions at this time.
• You will be asked to undress and change into a gown. A locker will be provided for your clothes.
• It is very important that you do not bring anything containing metal into the scanning room. Please leave all jewellery, credit cards, piercings, watches, mobile phones, and any other metal objects in the locker provided. Wedding bands do not have to be removed.
• Do not wear makeup on the day of the scan, as some make-up contains metal as part of the ingredients.

What happens during the scan?

• Breast MRI uses a special contrast medium which helps to take detailed pictures of the breast. This is called gadolinium-DTPA.
• The contrast medium is injected into a vein during the MRI via a small plastic cannula. The radiographer will place this cannula in your arm before the MRI.
• You will then be asked to lie on your front on the MRI couch.
• The radiographer will place your breasts through two holes in the couch.
• Please let us know if you are not comfortable as it is important that you lie absolutely still.
• The couch then slowly slides through the MRI scanner and the images are taken.
• The radiographer operates the MRI scanner from behind a partition. They will be able to see you throughout the procedure and you will be able to talk to each other through an intercom in the MRI scanner.

Further investigations

It is not unusual to need further investigation of the breasts following the MRI, with one in 10 women who have a breast MRI being called back for further appointments. However, in most cases, no problems are found.

Are there any side effects?

There are no after-effects from the MRI scan itself, and you will be free to drive and return to work should you wish. In very rare cases, some women can have an allergic reaction to the contrast medium used in breast MRI. The radiographers and doctors are all trained to deal with such reactions.

Contact numbers

• MRI Addenbrooke’s Hospital 01223 216559
• Cambridge Breast Unit 01223 217627