What to Know About a Fast MRI for Breast Cancer Screening

Fast breast MRI (or abbreviated MRI) for breast cancer screening is a relatively new technique designed to find breast cancer early. Compared with mammograms or 3D mammograms, it is more likely to detect cancer, especially more aggressive breast cancers. Mammograms miss roughly 15% of breast cancers and are less accurate in women with dense breasts. Compared with conventional breast MRIs, abbreviated MRIs are much less expensive (in some centers, similar to the cost of a mammogram) and take only around 10 minutes to perform.

Currently, fast MRI screenings for breast cancer are primarily being used in addition to mammograms for women with dense breast tissue (40% to 50% of women) for which mammograms are less accurate. It is also seen as having a niche as an "in-between" test for those who do not qualify for a conventional MRI but have a somewhat higher risk for developing breast cancer. However, some researchers propose that abbreviated MRI may one day replace mammography for the early detection of breast cancer in women of average risk.

Screening with abbreviated MRI is currently investigational and that current national guidelines do not include abbreviated MRI as a screening modality.

For women who have a high risk of developing breast cancer (defined as a 20% lifetime risk of developing the disease), conventional MRI is still recommended. Notably, one in eight women will develop breast cancer at some point in life, and 85% of these women have no family history of the disease.

Purpose of Fast MRI

At the current time, fast MRI (magnetic resonance imaging) or abbreviated MRI (AB-MRI) is designed as a test to be done in addition to a mammogram for women who have dense breast tissue (roughly 40% of women, though to different degrees). Dense breast tissue both increases the risk of developing breast cancer and makes the disease more difficult to find on a mammogram.

Traditionally, breast ultrasound has been the most common form of supplemental screening (used along with mammography) for women with dense breasts. It should be noted that the term "dense breasts" refers to breasts are found to have more dense tissue than fatty tissue in a mammogram.

Comparing Fast Breast MRI to Other Tests

Fast breast MRI will be compared to both mammograms (and 3D mammography) and conventional breast MRIs, but it's important to note some of the differences in the studies. In some studies, mammography or 3D mammography and fast breast MRI are compared directly. Other studies compare the use of mammography and ultrasound versus mammography and fast MRI. Yet, others compare fast MRI to conventional MRI.

Keep in mind that mammography is widely available, while abbreviated MRI is only performed at certain centers.

Comparison to Mammography

Compared to a traditional mammogram, fast breast MRI is much more likely to detect early breast cancers.

Early Detection and Missed Breast Cancers

On average, mammograms miss 15% of breast cancers, whereas it's rare that breast MRI misses breast cancer (this is one of the reasons why it is recommended for high-risk women).

Aggressive Breast Cancers

While mammograms are primarily an anatomic test, MRI's provide more information about physiology or function. Since MRIs can see blood flow (vascularity) and inflammation around tumors, they are more likely to detect breast cancers.

Radiation

Mammography involves a small amount of radiation exposure. On the other hand, MRI doesn't involve any radiation exposure.

Cost

In general, fast breast MRI is slightly more costly than mammography—one center reports the cost to be $250 for a fast breast MRI. Since it is now usually done as a supplemental test, is added to the cost of mammography.

In addition, most insurance companies don't yet cover the test, though the cost may be less than many insurance deductibles.

However, it's thought that fast MRI could potentially cost less than mammography over the long term as the test would not need to be done as often. For example, it may only need to be done every two years in a situation in which a mammogram was needed yearly.

A 2019 simulation study found that even though the initial cost of MRI screening in average-risk women was higher, it was actually more cost effective over time. Certainly, finding breast cancers early is less costly both physically and emotionally than findings them when they are larger or have spread. (Conventional MRIs are usually only covered by insurance for those who are high risk.)

Discomfort

Unlike mammography, MRI doesn't require chest compression, though it does require a needle stick for the contrast.

Ductal Carcinoma in Situ

There have been mixed results in studies looking at early detection and DCIS. Some studies have concluded that mammograms are more helpful (more sensitive) in detecting DCIS (by seeing breast calcifications). However, other researchers have found that MRI is a better test for testing intermediate or high-grade DCIS—tumors that need to be managed more aggressively. Since there is significant concern about overdiagnosis of DCIS, this could be an advantage.

False Positives

The issue of false positives (findings that falsely suggest cancer, but may require a biopsy, for instance) with MRI relative to mammogram has been a concern of some researchers. There are, however, important differences in the types of false positives with the two types of studies.

In a 2018 study, it was found that false positives attributed to breast MRI were more likely to be high-grade atypical proliferative changes (changes more likely to become cancerous), whereas false positives with digital mammography were more likely to be due to low-risk findings. In other words, not all false positives are equal.

Comparison With 3D Mammogram (Digital Breast Tomosynthesis)

Recently, 3D mammograms have become available as a way to detect more breast cancers in the early stage, and studies are currently in place comparing fast MRI (AB-MRI) to 3D mammograms. From previous studies, however, it appears that fast MRI may be far superior, with findings suggesting that it is up to three times more sensitive than 3D mammography.

It is thought that traditional mammography will detect breast cancer in four of 1,000 tests, 3D mammography somewhat higher at five in 1,000, with supplemental breast ultrasounds detecting another two to four cases of cancer (but risks more false positives). In comparison, abbreviated MRI will detect, on average, 16 to 23 more breast cancers per 1,000 women.

Comparison With Supplemental Breast Ultrasound Screening

Supplementing mammograms with breast ultrasound can detect more cancers, so researchers have set out to compare the combination of mammography with supplemental ultrasound studies against mammograms and supplemental fast MRI.

In a 2017 study of 2,120 women with no risk factors (which means a lifetime risk of breast cancer equal to 15% or less), the use of supplemental MRI every one year to three years in addition to mammograms was compared to mammograms with supplemental breast ultrasounds.

Fast breast MRI found an additional 60 cancers (40 of which were invasive). None of these cancers were found by ultrasound or mammography alone. In a different study, 11 cancers were found in 443 women who had both a negative screening mammogram and ultrasound.

It's likely that the cost of mammogram plus ultrasound is more than that of fast MRI, though not yet covered by many insurance plans. Breast ultrasound also results in many more false positives than fast MRI.

Comparison to Conventional MRI

Conventional breast MRI is the best screening tool for breast cancer and is considered the best option for people at high risk of developing the disease (have a lifetime risk of 20% or more). In fact, it is very rare for a breast MRI to miss life-threatening cancer. In addition to being able to visualize changes in blood vessels, cancers are not as easily hidden by normal tissues in an MRI.

That said, for people at high risk, conventional screening is recommended. This includes:

• people with BRCA gene mutations and their first degree relatives (first degree relatives include parents, siblings, and children)
• people with Li-Fraumeni syndrome, Cowden syndrome, or Bannayan-Riley-Ruvalcaba syndrome and their first-degree relatives 
• people with other gene mutations associated with breast cancer risk
• women who have had breast cancer in their other breast
• women who had radiation therapy to the chest at age 10 to 30 (such as for Hodgkin lymphoma)
• people with a lifetime risk of breast cancer of at least 20% based on a model such as BRCAPRO

Conventional MRI, however, is much more costly and takes around 45 minutes versus 10 minutes for an abbreviated MRI. It is also not considered cost-effective for women at average or intermediate risk. When considering cost, it's important to include not only the procedure but the cost (such as breast biopsy) of investigating abnormal results. (Again, it's worth noting that 85% of women who develop breast cancer do not have a family history of the disease.)

Whether fast MRI could be used for women of high risk is still unknown. A 2017 study comparing abbreviated breast MRI with conventional MRI in over 1,000 women found that the BIRADS score (interpretation made by a radiologist describing the likelihood that a cancer is present) changed in only 3.4% after the conventional test was done. Most of these changes didn't affect management (for example, whether or not a biopsy was recommended).

That said, a number of studies have found fast MRI to be comparable to conventional MRI with regard to follow-up after breast cancer surgery, for breast cancer staging, and for further evaluation of abnormalities found on mammogram screening.

Limitations

A significant limitation is that some people experience extreme claustrophobia with MRIs, even when medications for sedation are used.

Risks and Contraindications

As with any medical test, a fast MRI carries potential risks as well as reasons why the test should not be ordered (contraindications).

Potential Risks

There is a potential risk related to the contrast agent gadolinium used for the scans. A report in the journal The Lancet Neurology found that gadolinium accumulates in the deep nuclei of the brain, though the meaning of this is uncertain. Gadolinium was first approved as a contrast agent in 1988, and thus far no clinically meaningful problems have been documented.

Certainly, a major risk of any type of breast cancer screening is that of false positives and the emotional impact that involves.

Contraindications

The test cannot be performed on people who have metal implanted anywhere in the body, such as some pacemaker leads, metallic foreign bodies, "triggerfish" contact lenses, insulin pumps, and more.

Before the Test

Before your fast breast MRI your healthcare provider will talk to you about the reasons the test may be helpful. She will also carefully discuss your risk factors for breast cancer. If your risk is high (if your lifetime risk of developing breast cancer is expected to be 20% or greater), she may recommend that you have a conventional breast MRI instead.

It's also important that you gather previous breast imaging studies you have had so the radiologist can compare any findings with previous changes in your breasts.

Timing

Though the test itself takes only around 10 minutes to perform, you should reserve plenty of time when you make your appointment. This will include time to fill out any necessary forms, provide your insurance information, and to have an IV inserted through which the contrast will be delivered (gadolinium). Clinics vary, and though often you will go home and be informed of your results later, you may need to reserve time to discuss your results shortly after the test is performed.

Location

Currently, there are limited areas where abbreviated MRIs are being performed. Many of these are located in larger cancer centers or other facilities that have an MRI.

What to Wear

You will change into a gown for the procedure, so you can wear regular clothes to your appointment. You will have to remove anything metallic from your body, so it's best to leave jewelry (such as wedding rings) at home.

Food and Drink

There are no dietary restrictions prior to a breast MRI.

Cost and Health Insurance

Since abbreviated breast MRI is a very new procedure, many insurance companies are not yet covering the test. If you are of high risk, insurance usually does cover the cost of a conventional breast MRI. Many people will be required to self-pay for a fast MRI, and it's important to talk to your healthcare provider about this beforehand.

What to Bring

You should bring your insurance card to your appointment, as well as any other paperwork or previous films that are requested. You will be able to drive yourself to your appointment and back home again, but some people enjoy bringing a companion to keep them company while waiting and to help think of any questions to ask.

During the Test

When you arrive for your test, a radiology technician will meet with you and explain the procedure. The technician will ask you about any metal you may have in your body (which could be a contraindication to doing the test) and will make sure you don't have anything metallic remaining on your body. In some centers the radiologist will also talk to you about the test and what you can expect.

Pre-Test

When you arrive in the MRI suite, a technician will insert an intravenous needle into a vein. You may feel a sharp stick when the needle is introduced. The contrast agent, gadolinium, will then be injected through the IV. Unlike some contrast agents that can cause flushing, most people are unaware that the injection has been given.

Throughout the Test

You will be asked to lie down on the MRI table, and the technician will make sure you are comfortable. Though the technician will leave the room through the actual test, you will be in constant contact via a speaker, and the technician will check in often to see how you are doing. You will be given earphones to reduce some of the noise (MRI machines are noisy) and will be offered a choice of music to listen to during the procedure.

When you are ready, the table will slide into the tube for the MRI. MRI tubes are narrower than CT scan tubes, and some people experience claustrophobia. Closing your eyes before entering the tube can be helpful. Some people who are very claustrophobic may need a sedative before the procedure. If this is the case, you will have to bring a driver to take you home after the test.

As the test begins you will hear a whirring sound around you, and then loud "clunks" as the procedure continues. You should let your technician know if you feel claustrophobic or uncomfortable in any way during the procedure.

After the Test

When the test is completed, the table will slide out from under the MRI and you will be able to get ready to get home. Your IV will be removed, and a bandage placed to keep the site clean and decrease any bleeding.

Side effects are uncommon, though there is a very small risk of bleeding, bruising, or infection from the site where the IV was placed. You will either be allowed to return home or wait for the radiologist to talk to you about your images.

Interpreting Results

Your healthcare provider may call you to talk about the test, or instead have you make an appointment to discuss the results in person. Like mammograms, MRI reports provide information on the risk of breast cancer and any suspicious regions, though the terminology differs significantly.

Depending on your results, your healthcare provider may recommend further testing, such as a breast biopsy, or follow-up within a certain amount of time. Make sure to ask questions so that you understand your results and what they may mean to you.

A Word From Verywell

Fast or abbreviated MRI is a supplemental tool available for women of average or intermediate risk who have dense breasts. These tests are more likely to detect breast cancers, especially aggressive tumors. It is also more comfortable and radiation-free, but due to lack of insurance coverage at the present time, may be more costly.

The procedure is also being studied for other conditions, such as the detection of prostate cancer in men with elevated PSA tests. Due to its advantages with breast cancer, some believe that it may become the new standard for breast cancer screening in the future.