Breast MRI

	What is breast MRI
	What are the indications for breast MRI
	Can breast MRI replace a mammogram or breast ultrasound
	How accurate is breast MRI
	What about screening breast MRI in high-risks patients
	How is breast MRI performed
	What would prevent from having a breast MRI
	Who Interprets the results and how soon do I receive them
	Does Insurance pay for breast MRI
	If I need a breast MRI, where should I have it performed
	What happens if my breast MRI test shows something
	Breast MRI Indications

What is breast MRI?

Breast MRI is a breast imaging technique that is used for problem solving and for evaluation of local disease in the breast cancer patient. Breast MRI has a role in the evaluation of patients that have a high risk for the development of breast cancer (over 25% lifetime risk).

What are the indications for breast MRI and which patients may benefit from this test?

The most common indication for breast MRI in our experience is problem solving, or further evaluation of a finding seen on mammography. This is often in patients with dense (thick) breast tissue on mammography. Dense tissue is usually normal breast tissue which looks white on a mammogram, compared to fatty tissue which looks black. The dense tissue can obscure (hide) an abnormal process such as a cancer. Sometimes an area of normal dense tissue (called asymmetry) can look like a cancer. In either case, the MRI often can resolve the issue or problem.

Breast MRI is often used to define the local extent of a known breast cancer, and can help the doctor inform the patient regarding the correct treatment. In up to 40% of cases, MRI can show the extent of the cancer better than physical exam, mammography, or ultrasound. This is often the case for patients with dense breasts (often seen in the case of younger breast cancer patients). MRI can also be used to evaluate the response of a breast cancer to neoadjuvant chemotherapy (chemotherapy given before surgery).

Breast MRI is also used to evaluate breast implants.

Can breast MRI replace a mammogram or breast ultrasound?

No, breast MRI cannot replace a mammogram, or a breast ultrasound. The only exception is when the patient has had both breasts removed. In this case, the MRI is used as a primary imaging technique to assess the implants, residual breast tissue or the chest wall.

Mammography is currently still the best screening test for breast cancer. Mammography is very sensitive for the detection of microcalcifications (tiny calcium deposits in the breast). These small calcifications can be a sign of early breast cancer. Another sign of breast cancer is a mass or density seen on mammography. Dense (thick) breast tissue is usually the cause of a false negative mammogram. MRI Is very sensitive for breast cancer detection in patients with dense tissue, however, MRI does not visualize microcalcifications. Mammography and MRI are complementary tests (used together to evaluate the breast).

Breast ultrasound is usually not considered to be a screening test for breast cancer. Ultrasound is most often used to evaluate dense spots or areas seen on mammography. If a density is a simple cyst (fluid filled structure) on ultrasound, it is probably benign (not cancer). A solid structure (i.e. tissue, not simply fluid) on ultrasound may need to be evaluated further, depending on the appearance. Breast ultrasound is also complementary to mammography and breast MRI.

How accurate is breast MRI?

MRI is very sensitive for breast cancer (usually detects cancer if it is present). There are few breast cancers not seen by MRI, and these are usually detected by mammography. MRI has an overall accuracy of over 70% when performed correctly at experienced centers; this means that MRI predicts correctly whether the abnormality is benign or malignant over 70% of the time. We have validated our results (over 600 patients), and we meet or exceed these accuracy rates (accuracy of 80% for detected abnormalities).

What is the role of breast MRI for screening high risk patients?

The American Cancer Society recommends screening breast MRI for women with greater than a 20-25% lifetime risk for breast cancer, including women with a strong family history of breast or ovarian cancer and women who were treated for Hodgkin’s disease.

How is a breast MRI performed?

The patient lies on her stomach with her breasts surrounded (but not compressed) by an MRI imaging receiver (called a breast coil). The patient is comfortably positioned and an IV is placed in her arm. After this, the table that the patient is lying upon is advanced into the MRI magnet for 25-30 minutes of imaging. The imaging includes injection of a contrast agent, called Gadolinium, into the patient's vein. The use of the contrast agent is most important in order to detect abnormalities and cancer in the breast. Cancers and infections cause a different type of pattern on MRI than normal breast tissue. Unlike some facilities which only image one breast at a time, we perform MRI on both breasts the same day, even if the exam is only ordered for one side. We believe that this is in the best interest of the patient.

What would prevent me from having a breast MRI?

Patients with certain implanted or foreign devices may be at risk of physical harm by performing an MRI. All patients are screened over the phone and at the time of the exam regarding this issue.

There are several other circumstances under which patients should not have a breast MRI, or may need to reschedule to a more appropriate time. These circumstances may lead to false positive results:

1) MRI should not be performed during menstruation. Instead, the second or third week of the menstrual cycle is preferred.

2) MRI should be avoided if a patient is on hormonal therapy (of any kind except for birth control pills). In this case the hormonal therapy should be suspended for one month in order to have an optimal study.

3) MRI should be delayed for at least six months post radiation therapy. Delay for chemo should be at least one month. However, breast MRI can be performed in the first two weeks immediately following breast surgery.

4) Breast MRI should generally be avoided during pregnancy or the immediate post-partum period. Exceptions to these guidelines would require a conversation between the referring physician and radiologist in order to determine the best course of action for the patient.

Who interprets the results and how soon do I receive them?

A board certified diagnostic radiologist interprets the results. Breast MRI examinations involve a very large number of images. The radiologist will briefly review the exam while the patient is in the department, to determine if any more imaging is needed. The final interpretation is sent to the referring physician after a thorough review.

What is the reimbursement for breast MRI?

MRI is reimbursed by most carriers for the local assessment of breast cancer, and lesion characterization. Private insurance will usually pay if an abnormality or finding is present on physical exam, mammography or ultrasound. The reimbursement is variable for other indications, including high risk screening.

If I need a breast MRI, where should I have it performed?

This MRI test requires a higher field magnet (at least 1.5 Tesla), specialized breast imaging coils, high resolution technology, and appropriate software. Besides adequate technology, sites that perform this procedure should have adequate clinical experience (technologist and radiologist), and should have the capability to perform MRI guided biopsies or localizations. Optimally, sites that perform breast MRI should be able to evaluate both breasts at the same time. LRI is a qualified breast MRI site.

What happens if my breast MRI test shows something?

Since the accuracy of MRI is less that 100%, sometimes it detects an abnormality that has the appearance of cancer, but is benign. This can occur with normal breast tissue and can simply be related to hormones or may have a benign appearance; in these cases a follow-up scan in three to six months can be performed.

In some cases, an abnormality is detected that is more concerning. In most of these cases, a focused ultrasound exam is able to find the area. Once the area is detected, a needle biopsy can be performed. If the area (abnormality) cannot be seen on ultrasound, it can be biopsied with MRI guidance, or MRI can be used to place a clip for surgical removal (LRI has the capability to perform either of these procedures).

Breast MRI Indications:

Patients with dense breasts with indeterminant findings on mammogram, ultrasound and physical exam
Concern for multiple tumor sites when breast conservation is being considered
Post-surgical and post-irradiation patients with indeterminant findings (at least 6 months post-irradiation to decrease false positives)
Suspected breast primary with malignant axillary adenopathy (negative physical exam and mammogram; and Implant evaluation.
Mutation of BRCA1 / BRCA2 genes
Radiation treatment to chest 10-30 years old (Hodgkin’s treatment)
Strong family history - two or more close relatives developed breast/ovarian cancer before age 50
Recently diagnosed breast cancer
- To asses for multifocal disease
- Up to 5 – 10% chance of cancer in contralateral breast