Spotlight on Breast MRI

Breast MRI is a powerful tool for detecting and evaluating areas of concern in breast tissue. The technology uses strong magnets to make images of the breast tissue. There is no radiation exposure in an MRI, but often a liquid contrast dye containing gadolinium will need to be injected through and IV during the exam to give the radiologists more information. Images from breast MRI must be compared to other breast studies, any symptoms and the clinical breast exam.

Reasons to have a Breast MRI:

• Screening :Proactively looking for early signs of a problem when you feel well and have no sympotoms. There are two different types of screening breast MRI:

  • Yearly full screening MRI for High Risk Patients: This is usually offset 6 months from annual mammogram. Qualifying patients have a lifetime risk of having breast cancer of 20% or greater. Multiple factors contribute to breast cancer risk. The ACR recommends all women age 25 and over have their breast cancer risk score calculated. Other reasons to have high risk screening breast MRI include a strong family history of breast cancer, a personal history of breast cancer either with dense breast tissue or diagnosed under the age of 50 regardless of breast tissue density, or a history of radiation to the chest for previous cancer treatment. This exam take 30-45 minutes and requires a contrast injection. It gives more detailed information about the breast tissue than an abbreviated protocol screening breast MRI.

  • Abbreviated protocol MRI for Average Risk Patients with dense breast tissue: This exam takes 10-15 minutes and requires a contrast injection. Most insurance companies do not cover, but it is much less expensive than an full screening MRI. Recommendations are in flux for frequency of screening, but currently recommended every 1-2 years in the United States. New research may extend this interval for average risk women.

• Diagnostic: This exam gives more information about a known issue. It is a 30-45 minute exam and is often obtained along with other studies to fully show the area of concern. There are many reasons your doctor may order a Diagnostic Breast MRI including:

  • Evaluating extent of disease with newly diagnosed cancers. This looks at how large the cancer is, but also at the rest of the tissues in both breasts and armpits to determine if there are other areas of concern. Approximately 15% of patients diagnosed with cancer may have additional cancer in the other breast.

  • Lumpectomy bed evaluation with positive margins to see if there is cancer left in the breast after a surgery.

  • Response to neoadjuvant chemotherapy. If your cancer treatment plan includes chemotherapy given before surgery to shrink the tumor, breast MRI is a useful tool to monitor the response of the tumor to the medications.

  • Evaluation of breast cancer recurrence versus post-surgical change. There is an overlap in the appearance of normal, expected changes after surgery and the appearance of cancer on a mammogram. Sometimes breast MRI or a biopsy may be needed to tell the difference.

  • Looking for a breast cancer if cancer is found in nearby lymph nodes, but the mammogram is unremarkable. This rare phenomenon is called cancer of unknown primary (CUP) syndrome. The most likely cause of a metastatic cancer in an axillary or armpit lymph node is breast cancer,

  • For more information if other breast imaging is inconclusive

• Implant protocol breast MRI: This exam checks that implants are intact. No intravenous liquid contrast is needed or given. This exam looks only at the implant and is not used to look for breast cancer. The test can show if there is an implant rupture as well as what type of rupture. Depending on the type of implant you have, this may be recommended every 2-3 years.

• Procedure guidance: Both biopsy and preoperative needle localization can be performed with MRI guidance. This procedure is usually reserved for suspicious findings seen only on MRI without a likely match on ultrasound or mammography. The recommendation for this procedure typically comes from a radiologist or other breast care specialists after a complete workup has been performed.

Breast MRI does not replace evaluation with mammography and ultrasound as there are early changes from breast cancer that can only been seen on a mammogram or ultrasound. However it is a useful addition to these exams for many patients. Breast MRI does not replace careful problem solving by the radiologist using other exams and also should not be used instead of breast biopsy if one has been recommended by the radiologist. Breast MRI is not for everyone. If you have the following considerations, you may need to talk to your doctor before proceeding: Implantable devices, allergy to gadolinium contrast, kidney problems, pregnancy, lactation, anxiety or claustrophobia (talk to your ordering doctor). A technologist will help determine that it is safe for you to have an MRI exam before your appointment by asking your questions from the safety questionnaire.

For more information, see the ACR practice parameters on breast MRI.