Your Mammogram Says “Dense.” What That Means, and Who Pays for the Next Test

Since September 2024, every mammogram result in the US must tell you whether your breast tissue is dense. About four in ten women are told it is. What the letter means, which follow-up tests exist, and what Florida coverage looks like in 2026.

By Teona Abuladze · 7 min read

The paragraph is the same in every state, because the federal government wrote it:

“Breast tissue can be either dense or not dense. Dense tissue makes it harder to find breast cancer on a mammogram and also raises the risk of developing breast cancer. Your breast tissue is dense. In some people with dense tissue, other imaging tests in addition to a mammogram may help find cancers. Talk to your healthcare provider about breast density, risks for breast cancer, and your individual situation.”

It has been required on mammogram results across the country since 10 September 2024, under an FDA rule updating the Mammography Quality Standards Act. Women whose tissue is not dense get a shorter version that ends in the same place: talk to your provider.

The letter doesn’t say what that conversation should cover, or who pays for whatever comes after it.

What “dense” means

A breast is fat plus fibrous and glandular tissue. On a mammogram, fat shows up dark and dense tissue shows up white. So do most tumours, which is the whole problem.

Radiologists put every breast into one of four categories:

• A: almost entirely fatty
• B: scattered areas of fibroglandular density
• C: heterogeneously dense, “which may obscure small masses”
• D: extremely dense, “which lowers the sensitivity of mammography”

C and D count as dense. Very roughly, one woman in ten is in A, four in B, four in C and one in D. A 2014 study in the Journal of the National Cancer Institute estimated that 43 percent of American women aged 40 to 74 have dense breasts, about 27.6 million women, and nearly half of them are in their forties.

Density is normal. It is also a risk factor on its own: the American Cancer Society lists dense breast tissue among factors that raise relative risk by 2.1 to 4 times.

Your letter says only “dense” or “not dense.” The category, A to D, goes to your doctor’s report. Ask for it.

The difference between C and D matters. Much of the strongest evidence for extra screening comes from women in category D.

The tests that can come next

Ultrasound is the most familiar add-on and the least expensive. MRI uses a contrast dye through a vein; a shorter “abbreviated” or “fast” MRI takes around ten minutes in the scanner. Contrast-enhanced mammography is a newer option that also uses dye.

The evidence has moved in the last two years.

In the Dutch DENSE trial, published in 2019, 40,373 women aged 50 to 75 with extremely dense breasts were split into two groups. Among those offered MRI, cancers that appeared between screening rounds fell to 2.5 per 1,000, against 5.0 with mammography alone. The price was false alarms: about 80 per 1,000 MRI screens.

The British BRAID trial, reported in The Lancet in May 2025, took more than 9,000 women with dense breasts whose mammograms had been normal. Abbreviated MRI found 17 additional cancers per 1,000 women, contrast-enhanced mammography 19, and automated ultrasound 4. Those are interim results, and the trial cannot yet say whether fewer women die.

Two other trials are worth knowing. WISDOM, published in JAMA in December 2025 with more than 28,000 women aged 40 to 74, found that screening tailored to each woman’s risk, density included, was a safe alternative to annual screening for everyone. MASAI, in The Lancet in January 2026, followed more than 100,000 Swedish women and found that mammograms read with AI support led to 12 percent fewer cancers being found between screening rounds, without more false positives.

What the guidelines say

The US Preventive Services Task Force changed its advice in April 2024: mammograms every two years for women aged 40 to 74. On dense breasts it concluded that the evidence is “insufficient” to recommend for or against extra ultrasound or MRI.

The American College of Radiology goes further. It recommends yearly mammograms from 40, a risk assessment for every woman by 25 (with particular attention to Black and Ashkenazi Jewish women), and MRI for some women with dense breasts and a personal history of breast cancer.

The two bodies are looking at the same studies and weighing the harms differently.

Who pays, federally

From plan years starting in January 2026, most private insurance must cover, with no copay or deductible, additional imaging and biopsies when a screening mammogram shows that more is needed to finish the job. The rule comes from guidelines the Health Resources and Services Administration adopted in December 2024, and it also covers “patient navigation,” someone to help you get through the follow-up.

The gap: this applies when the mammogram shows something. A normal mammogram plus a “dense” letter is a different situation, and routine extra screening in that case is not clearly covered.

A federal bill to close that gap, the Find It Early Act, was introduced in the Senate in April 2025 (S. 1410, Klobuchar and Marshall) and in the House in November 2025 (H.R. 6182, DeLauro). As of early 2026 neither had passed. About 30 states have passed their own coverage laws.

Who pays in Florida

Florida is not one of the generous ones.

In May 2025 Governor DeSantis signed SB 158, sponsored by Senator Lori Berman, who is a breast cancer survivor. It passed 38–0 in the Senate and 116–0 in the House. It bans cost-sharing for supplemental breast exams, but only in the state group insurance plan, meaning state employees. It took effect on 1 January 2026. “People often can’t afford the next step,” Berman said.

A 2026 bill to extend that protection to Medicaid and private insurers, HB 137, died in a House subcommittee in March.

Unless you are a Florida state employee, no Florida law makes extra screening for dense breasts free.

What it costs depends on the plan. GoodRx puts the average cash price of a breast MRI at about $950; an abbreviated MRI runs roughly $250 to $500 and is often not covered. A 2023 study in JAMA Network Open of about 231,000 commercially insured women found that the more a plan made women pay, the fewer went on to have follow-up imaging.

The part that doesn’t fit on a poster

More screening finds more cancers. It also finds things that turn out to be nothing, and occasionally cancers that would never have caused harm.

The Task Force’s own modelling puts numbers on its 2024 decision. For every 1,000 women screened every two years from 40 instead of 50, it estimated 1.3 more breast cancer deaths averted, 503 more false-positive recalls, 65 more biopsies that come back benign, and 2 more cases of overdiagnosis. Over ten years of yearly screening, about half of women get at least one false-positive recall.

None of the extra-screening trials has yet shown that women with dense breasts live longer because of it. That is why the Task Force will not recommend it, and why radiologists who see the cancers mammograms miss find that position hard to accept.

The burden is not equal either. Black women are about 40 percent more likely than white women to die of breast cancer. For Hispanic women, breast cancer is the leading cause of cancer death, and 60 percent are diagnosed at the earliest, localised stage against 68 percent of white women. And incidence among women under 50 has been rising about 1.4 percent a year.

Four questions for the appointment

Are my breasts category C or D?

Given my density, age and family history, what is my estimated lifetime risk?

If you think I need more imaging, which test, and will it be billed as screening or as diagnostic?

What will I owe? Call the insurer with the answer to the last question before you book.

Teona Abuladze is the founder and editor of Shansi Magazine.

If you are facing a diagnosis or waiting on results, the American Cancer Society’s helpline is open around the clock at 1-800-227-2345.

Sources: Federal Register, FDA final rule amending MQSA, 10 March 2023 — https://www.federalregister.gov/documents/2023/03/10/2023-04550/mammography-quality-standards-act ; DenseBreast-info, required notification wording — https://densebreast-info.org/legislative-information/fda-national-dense-breast-reporting/ ; DenseBreast-info, density categories — https://densebreast-info.org/providers-faqs/how-is-breast-density-determined/ ; JNCI 2014 estimate (via Newswise) — https://www.newswise.com/articles/study-estimates-number-of-u-s-women-potentially-impacted-by-breast-density-notification-legislation ; American Cancer Society, Breast Cancer Facts & Figures 2024 — https://www.cancer.org/content/dam/cancer-org/research/cancer-facts-and-statistics/breast-cancer-facts-and-figures/2024/breast-cancer-facts-and-figures-2024.pdf ; ACS, Cancer Facts & Figures for Hispanic/Latino People 2024–2026 — https://www.cancer.org/content/dam/cancer-org/research/cancer-facts-and-statistics/cancer-facts-and-figures-for-hispanics-and-latinos/2024/2024-2026-cancer-facts-and-figures-for-hispanics-and-latinos.pdf ; USPSTF recommendation, April 2024 — https://www.uspreventiveservicestaskforce.org/uspstf/document/ClinicalSummaryFinal/breast-cancer-screening ; USPSTF modelling study — https://www.uspreventiveservicestaskforce.org/uspstf/document/modeling-study/breast-cancer-screening ; American College of Radiology guidelines (Elsevier release) — https://www.elsevier.com/en-gb/about/press-releases/new-acr-breast-cancer-screening-guidelines-call-for-earlier-and-more-intensive-screening-for-high-risk-women ; HRSA Women’s Preventive Services Guidelines — https://www.hrsa.gov/womens-guidelines ; IFEBP on 2026 coverage — https://blog.ifebp.org/what-group-health-plans-should-know-about-additional-breast-cancer-screening-coverage-in-2026/ ; DenseBreast-info on HRSA update — https://densebreast-info.org/updated-federal-breast-screening-recommendations/ ; Find It Early Act, S. 1410 — https://www.govinfo.gov/content/pkg/BILLS-119s1410is/html/BILLS-119s1410is.htm ; H.R. 6182 — https://www.govinfo.gov/app/details/BILLS-119hr6182ih ; Radiology Business on state laws, Feb 2026 — https://radiologybusiness.com/topics/healthcare-management/healthcare-policy/momentum-builds-several-states-propose-supplemental-breast-imaging-legislation-2026 ; Florida Senate, SB 158 (2025) — https://flsenate.gov/Committees/BillSummaries/2025/html/158 ; Florida Phoenix — https://floridaphoenix.com/2026/01/01/pet-insurance-law-ban-on-cost-sharing-for-supplemental-breast-exams-take-effect/ ; Florida Senate, HB 137 (2026) — https://flsenate.gov/Session/Bill/2026/137 ; DENSE trial (ASCO Post) — https://ascopost.com/news/december-2019/how-effective-is-supplemental-mri-screening-for-women-with-extremely-dense-breasts/ ; BRAID trial (University of Cambridge) — https://www.cam.ac.uk/research/news/enhanced-breast-cancer-screening-in-the-uk-could-detect-an-extra-3500-cancers-per-year-trial-shows ; WISDOM trial (NIH) — https://www.nih.gov/news-events/nih-research-matters/testing-risk-based-breast-cancer-screening ; MASAI trial (ecancer) — https://ecancer.org/en/news/27721-ai-supported-mammography-screening-results-in-fewer-aggressive-and-advanced-breast-cancers-finds-full-results-from-first-randomised-controlled-trial ; False positives over ten years (ScienceDaily) — https://sciencedaily.com/releases/2022/03/220325122711.htm ; GoodRx, breast MRI cost — https://www.goodrx.com/conditions/breast-cancer/breast-mri-cost ; Radiology Business on JAMA Network Open 2023 cost study — https://radiologybusiness.com/topics/medical-imaging/womens-imaging/follow-imaging-after-mammogram-breast-mri-jama