What is MRI of the Breast?

Magnetic resonance imaging or MRI uses a magnetic field, radio waves, and a computer to create three-dimensional images of the breast. MRI of the breast is one of the most sensitive imaging tools available for detecting new or recurrent breast cancer.

What is the role of breast MRI?

Breast MRI is very useful in evaluating the extent of cancer within the breast in a patient with a new diagnosis of breast cancer. It helps identify additional occult breast cancers in the involved breast in 15% to 30% of patients and also helps identify occult cancer in the opposite breast in up to 3% to 7% of patients. This means that later recurrences can be reduced and your surgeon can recommend the best surgical procedure for you now with the added information provided by a breast MRI. A negative breast MRI is approximately 90% sensitive for excluding breast cancer.

Breast cancer is not a single entity but rather a heterogeneous group of numerous disease subtypes. Invasive breast cancer comprises the largest subgroup approximately 70% while ductal carcinoma in situ (DCIS) comprises 20%. MRI is currently the most sensitive imaging modality to identify most invasive breast cancers with published sensitivities rangeing between 89% and 100%. The sensitivity for diagnosing non invasive breast called Ductal Carcinoma in Situ (DCIS) is somewhat lower but remarkably up to 40% of DCIS is diagnosed only with breast MRI.

The specificity of a breast MRI is improved when the information from the breast MRI exam is combined with information from a patient’s mammogram and ultrasound studies. It is for this reason a patient will receive a full mammographic and sonographic workup prior to a breast MRI exam. It is also possible a patient will be asked to return for additional mammographic and sonographic evaluation after the breast MRI exam even though a patient has had a complete workup prior to the MRI exam. This is because a directed mammogram or ultrasound study looking at a particular region can reveal more information than an exam looking at the entire breast.

Clinical Indications for Contrast Breast MRI

• Extent of disease in newly diagnosed breast patients.

• Response to chemotherapy for extensive breast cancers.

• Post operative evaluation for close or positive margins.

• Evaluation of scar versus recurrent breast cancer.

• Detection of occult primary tumors when presenting finding is an abnormal
lymph node(s).

For problem mammograms or equivocal physical findings in select patients. This includes the diagnosis of lobular invasive cancer which is frequently difficult to diagnose.

High risk patients: American Cancer Society recommendations

Patients testing positive for the BRCA gene
- First degree relative of BRCA gene mutation carrier
- Lifetime risk of 20 - 25% or greater including strong family history of breast or
ovarian cancer
- Radiation to chest between ages 10 to 30 such as Hodgkins disease
- Rare syndromes associated with breast cancer

Breast Implant rupture (NON CONTRAST MRI)

How is the procedure performed?

The breast MRI exam is performed in a large magnet which is like a very large tube. The patient lies on her (his) stomach. The breasts hang into a cushioned opening on the table. The table moves freely into and out of the magnet. A contrast injection is needed to identify a breast cancer. The contrast is administered through an intravenous catheter, which will be place in a patient’s arm or hand by a nurse or technologist prior to the exam. The contrast agent, gadolinium, is generally very safe with very few side effects, but is not recommended for individuals with kidney failure. Patients will be asked to lie very still while the machine acquires the images. It is extremely important not to move during the exam because motion during the exam causes image blurring and limits accurate interpretation of the exam. It is not uncommon to feel anxious about a breast MRI exam or feel uncomfortable because of the tight space of the magnet (claustrophobia). Short acting anti-anxiety medication can be administered as a tablet prior to the exam. Anyone receiving anti-anxiety medication will need to have a friend or family member drive them home after the exam. Imaging is done in sequences, each lasting between one and fifteen minutes. When images are being acquired a tapping or thumping sound is heard. Head phones and music are offered to help dampen the noise.

After an initial series of scans, the contrast is injected into the intravenous line. Additional series of images are taken following the injection. When the exam is completed, a patient will wait a short time on the table while the images are evaluated to ensure no additional images are needed. The intravenous line will be removed when the exam is completed. The imaging session lasts 30-45 minutes. The total exam will take approximately 60-90 minutes.

How should I prepare for the procedure?

Usually there are no special preparations or diet instructions prior to a breast MRI exam. You should continue medications prescribed by your doctor unless informed otherwise. You will be asked to change into a gown. Any metal such as earrings, eyeglasses, or hairpins must be removed. Women should always inform their technologist if there is any possibility of pregnancy. Please inform your doctor or the technologist if you have any of the following that may prevent you from undergoing an MRI exam:

• Pacemaker
• Aneurysm clips
• A history of working with metal
• Implanted drug infusion device
• Metallic plates, pins, screws or other implants (usually do not cause a problem
if they have been in place more than 4 to 6 weeks)

How Do I Get The Results?

After your study is over, the images will be evaluated by one of our board-certified Radiologists with expertise in MRI. A final report will be sent to your doctor, who can then discuss the results with you in detail. Should you have any questions regarding your MRI scan, we will be happy to discuss them with you.