What is MRI?
Magnetic resonance imaging (MRI) uses magnetic fields to create an image of the breast. MRI is different than mammography because a contrast agent is given through an IV before the procedure. MRI has mostly been used in breast cancer diagnosis and staging, rather than in screening. However, there is growing evidence that MRI in combination with mammography, compared to mammography alone, can increase detection of breast cancer.
The MRI Exam
The MRI examination room is occupied by a large magnet and a padded scanning table. The technologist will help you lie down on the table. Once you are comfortable, the scanning table slides into the center of the magnet. During the procedure you will hear intermittent thumping and humming sounds. Ear plugs are provided to ensure your comfort. It is important that you remain relaxed and completely still during the scan. You will be able to communicate with the MRI technologist at all times via an intercom system. If you wish, a family member or friend may accompany you into the MRI examination room.
Breast MRI is the recommended modality for screening patients with an elevated risk of developing breast cancer. Those who should add Breast MRI to their breast screening program are:
Women at high risk - The American Cancer
Society's guidelines for the early detection of breast cancer include annual screening using Breast MRI in addition to traditional mammography for women at high risk of the disease including 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
- Have a lifetime risk of breast cancer of 20%-25% or greater, according to risk assessment tools that are based mainly on family history*
- Had radiation therapy to the chest when they were between the ages of 10 and 30 years old Have Li-Fraumeni symdrone, Cowden syndrome, or Bannayan-Riley-Ruvalcaba syndrome, or have a first-degree relative with one of these syndromes
Women at moderately increased risk
The ACS also recommends women at moderately increased risk to talk with their doctors about the benefits of adding Breast MRI to their yearly mammogram. This includes those who:
- Have a lifetime risk of breast cancer of 15%-20% according to risk assessment tools that are based mainly on family history*
- Have a personal history of breast cancer, ductal carcinoma in situ (DCIS), lobular carcinoma in situ (LCIS), atypical ductal hyoerplasia (ADH), or atypical lobular hyperplasia (ALH)
- Have extremely dense breasts or unevenly dense breasts when viewed by mammograms
Women who have had breast augmentation (cosmetic or reconstructed)
- Breasts with significant scar tissue
- Silicone implants to screen for silent rupture
Additional risk factors
- An immediate family history of breast, ovarian or prostate cancer
- Early onset of menstrual periods
- Late birth of first child or no children
- Long-term hormone replacement therapy
In addition to screening, Breast MRI is useful in gathering more information about an area in the breast that is suspicious or already confirmed to be cancerous. Breast MRI should be used for diagnostic purposes when:
- Evaluating a person who has a palpable mass that isn't visible with mammography
- Evaluating a lesion in dense breast tissue
- Evaluating a person who has breast cancer cells in an underarm lymph node, but no breast mass is palpable or seen in a mammogram
- Determining if cancer is limited to one area of the breast, or if it's multicentric
- Checking a woman's other breast for signs of cancer after she receives her initial cancer diagnosis. The ACS recommends that Breast MRI be used to check the other breast for any signs of cancer in every newly diagnosed patient.
- Examining breast tissue in women who have implants
Evidence shows that Breast MRI is exceedingly important in surgical treatment planning for women who are newly diagnosed with breast cancer. It has been proven to help:
- Determine the status of the contralateral breast
- Check for occult lesions in the same breast Improve the success rate of lumpectomies
Because of it's high sensitivity, Breast MRI can be very useful when imaging the post-surgery breast. Among the advantages are it's ability to:
- Distinguish recurrence in the reconstructed breast.
- Differentiate scar tissue from recurrence