The short answer: A breast MRI uses a strong magnet, radio waves, and an IV contrast dye to make detailed pictures of breast tissue, with no radiation. It adds to a mammogram and does not replace it. The American Cancer Society advises a yearly MRI plus a yearly mammogram, usually from age 30, for women at high risk: a lifetime risk of about 20% to 25% or more, a BRCA1 or BRCA2 change, or chest radiation before age 30. Women with dense breasts may also be offered one, but the major groups disagree on that point.

What is a breast MRI and how is it done?

A breast MRI is an imaging test that uses powerful magnets and radio waves to make pictures of the breast and nearby tissue. MedlinePlus notes that it does not use x-rays and is "not a replacement for mammography."

Here is what usually happens:

  • Position: You lie face down on a padded table. Your breasts hang down into cushioned openings in the table.
  • Contrast: A technologist places an IV in your hand or arm. A gadolinium-based contrast dye goes in through that line. The American Cancer Society (ACS) notes that, unlike mammograms or ultrasound, breast MRI needs this dye. It makes abnormal areas easier to see.
  • Time: The ACS says a full exam usually takes about 30 to 45 minutes. MedlinePlus gives a range of 30 to 60 minutes.
  • Noise: The scanner makes loud thumps and hums, so you get earplugs or headphones.

You need to hold still, often with your arms above your head. If tight spaces bother you, these tips for MRI claustrophobia can help. For more on the dye itself, see our guide to MRI with contrast. MedlinePlus calls gadolinium very safe and says allergic reactions are rare. Tell your care team if you have kidney disease or are on dialysis.

Who should get a screening breast MRI along with a mammogram?

Screening MRI is for women at high risk, not for everyone. The ACS guideline (last revised July 2026) recommends a breast MRI and a mammogram every year, typically starting at age 30, for women who:

  • Have a lifetime breast cancer risk of about 20% to 25% or greater, based on risk tools that rely mainly on family history.
  • Have a known BRCA1 or BRCA2 gene change.
  • Have a parent, sibling, or child with a BRCA1 or BRCA2 change and have not been tested themselves.
  • Had radiation therapy to the chest before age 30.
  • Have Li-Fraumeni, Cowden, or Bannayan-Riley-Ruvalcaba syndrome, or a first-degree relative with one of them.

The ACS recommends against MRI screening when lifetime risk is under 15%. It finds not enough evidence for or against yearly MRI at 15% to 20% risk, or after a past breast cancer, DCIS, LCIS, or atypical hyperplasia.

The American College of Radiology (ACR) 2023 update goes further. It calls breast MRI the supplemental screening method of choice for most higher-risk women. It advises MRI starting at ages 25 to 30 for women with a genetic risk, a calculated lifetime risk of 20% or more, or chest radiation at a young age. It also advises a yearly MRI for women diagnosed with breast cancer before age 50, and for women with a past breast cancer plus dense breasts. The ACR wants every woman to have a risk assessment by age 25, especially Black women and women of Ashkenazi Jewish heritage.

What if my mammogram report says I have dense breasts?

Since September 10, 2024, every U.S. mammography facility must tell you whether your breasts are dense. The FDA's updated Mammography Quality Standards Act rule sets the exact wording. For dense tissue, the summary says dense tissue "makes it harder to find breast cancer on a mammogram and also raises the risk of developing breast cancer." It adds that "other imaging tests in addition to a mammogram may help find cancers."

What to do next is where expert groups split:

  • ACR: For women with dense breasts who want supplemental screening, breast MRI is recommended. If MRI is not possible, contrast-enhanced mammography or ultrasound could be considered.
  • ACS: Not enough evidence to recommend for or against yearly MRI for extremely or heterogeneously dense breasts alone.
  • USPSTF: The U.S. Preventive Services Task Force (2024) found the evidence "insufficient" to weigh the benefits and harms of supplemental ultrasound or MRI in women with dense breasts and a normal mammogram.

So density alone is a reason to talk with your clinician, not an automatic MRI order. Your full risk picture matters more than one line on a report. For more on mammogram reports and density, see mammogram.md.

How much more does MRI find, and what are the downsides?

The strongest trial is DENSE, from the Netherlands. It enrolled 40,373 women aged 50 to 75 with extremely dense breasts and a normal mammogram. The results showed:

  • Interval cancers (cancers found between screens) fell from 5.0 to 2.5 per 1,000 screenings in the group invited to MRI.
  • Among women who had the MRI, it found 16.5 extra cancers per 1,000 screenings.
  • The false-positive rate was 79.8 per 1,000 screenings.
  • Of the MRI findings sent to biopsy, 26.3% were cancer.

In plain terms, MRI catches cancers a mammogram misses. It also flags many spots that turn out to be harmless. The ACS says this can mean extra tests or biopsies, which is why it does not advise MRI for women at average risk. MRI can also miss some cancers a mammogram finds, such as those that show only as tiny calcium deposits. That is why MRI is added to a mammogram, not used alone.

Cost is another factor. The ACS notes that breast MRI "can cost a lot" and may need insurer approval first. It says most private plans that cover screening mammograms also cover MRI when a person is shown to be at high risk.

What is an abbreviated breast MRI?

An abbreviated MRI takes fewer image sets. The ACS says it usually takes about 10 minutes. It still uses contrast dye.

A 2020 JAMA study tested it in 1,444 women aged 40 to 75 with dense breasts. Each woman had both an abbreviated MRI and a 3D mammogram (tomosynthesis). Abbreviated MRI found invasive cancer at 11.8 per 1,000 women, compared with 4.8 per 1,000 for 3D mammography. Its specificity was lower: 86.7% versus 97.4%. That means more false alarms. Not every center offers the short protocol, and insurance coverage varies.

When is a breast MRI used for diagnosis instead of screening?

Many breast MRIs are not screening tests. According to the ACS and MedlinePlus, doctors also use breast MRI to:

  • Measure the size of a newly diagnosed cancer and look for other tumors in the same or opposite breast.
  • Sort out an unclear mammogram or ultrasound result, or a symptom such as suspicious nipple discharge.
  • Check silicone implants for leaks or rupture. The ACS notes it is not used for saline implants.
  • Tell scar tissue from a tumor after surgery, and check for cancer left after treatment.
  • Guide a biopsy of a spot seen only on MRI.

Because of that last point, the ACS suggests a center with a dedicated breast coil that can do MRI-guided biopsy, or one that partners with such a center. For how MRI fits with other cancer imaging, see can an MRI detect cancer.

The bottom line

A breast MRI is a contrast-enhanced, radiation-free scan that finds more cancers than a mammogram but also more false alarms. Women at high risk (a lifetime risk of about 20% or more, a BRCA change, certain syndromes, or chest radiation before 30) should get one every year along with a mammogram. Dense breasts alone are a gray zone: the ACR supports MRI, while the ACS and USPSTF say the evidence is not yet enough. Ask your clinician for a formal risk assessment, ideally by age 25 to 30.

Last updated: October 2026. This article is for informational purposes only and does not constitute medical advice. Talk with your doctor about your personal breast cancer risk and which screening tests fit you.