Maryland’s New Breast Arterial Calcification Law: What Radiology Leaders Need to Know

As of October 1, 2026, Maryland is the first state to require mammography centers to tell patients about breast arterial calcification (BAC). The finding has long appeared on mammograms, but practices have reported it inconsistently. Under House Bill 1364 (Chapter 604 of 2026), every screening results letter a Maryland center sends must now include a standard BAC notice. The notice tells patients that BAC may signal a higher risk of cardiovascular disease and encourages them to talk with their physician.

For radiology leaders, the law has two parts. The compliance part is simple: update your letter template. The operational part is harder. Once patients are told to ask about BAC, you need to answer the question consistently, and the referring physician needs to know what to do next.

Download our summary.

What the law new Maryland BAC law requires

HB 1364 amends Section 20-115 of Maryland’s Health-General Article, the same section that has governed the state’s breast density notice. Gov. Wes Moore signed it on May 26, 2026, after it passed both chambers without a dissenting vote.

• Who must comply: any “center” that produces, develops, or interprets screening or diagnostic mammograms. That includes hospitals, outpatient departments, radiology practices, imaging clinics, labs, and provider offices. VA facilities are exempt.
• What goes out: a notice with wording set in the statute, included in the screening results letter the center already sends to patients under the federal Mammography Quality Standards Act (MQSA).
• Who can change the wording: the Maryland Department of Health can revise the notice by regulation if it finds significant differences between the text and current medical evidence on BAC.
• Liability: the BAC provision may not be construed to create a standard of care, obligation, or duty that provides a basis for a cause of action.
• Effective date: October 1, 2026.

The required notice

“This notice contains the results of your recent mammogram, including information about breast arterial calcification.

If your mammogram shows breast arterial calcification, you should know that breast arterial calcification is a common finding. However, breast arterial calcification may be an indicator of an increased risk of cardiovascular disease. If you have breast arterial calcifications, please discuss this with your physician to assess your cardiovascular risks and determine if additional testing may be appropriate for you.

This information about the result of your mammogram is given to you to raise your awareness and to inform your conversations with your physician. Together you can decide whether additional screening options are right for you based on your mammogram results, individual risk factors, or physical examination. A report of your results was sent to your physician.”

Md. Code, Health-General § 20-115(d), as enacted by Ch. 604 (HB 1364), 2026

Why BAC is getting attention now

BAC is calcification in the medial layer of the breast arteries. It is a different finding from the microcalcifications radiologists evaluate for breast cancer. Radiologists have traditionally treated it as incidental, but evidence linking it to cardiovascular risk has grown, especially as AI tools make it possible to measure BAC on every exam.

• It’s common, and more common with age. A 2026 multicenter study in JACC: Cardiovascular Imaging of 21,514 women with no known cardiovascular disease found BAC in 22.7% overall. That ranged from about 8% of women under 50 to 61% of women over 70.
• It adds predictive value. In that study, each 10-percentile increase in age-adjusted BAC was associated with a higher risk of major adverse cardiovascular events, independent of conventional risk factors. Adding BAC to standard risk models improved discrimination (C statistic 0.67 to 0.71), especially for women rated low or intermediate risk.
• Severity matters. A 2026 European Heart Journal analysis of more than 120,000 women, using AI quantification, reported that cardiovascular event risk rose with BAC severity. Severe BAC was associated with roughly two to three times the risk.
• It is a risk marker, not a diagnosis. BAC detects obstructive coronary artery disease poorly. A SCOT-HEART sub-study found an AUC of about 0.55. Its value lies in flagging women who may need a closer look at cardiovascular risk, not in finding specific coronary lesions.

Heart disease remains the leading cause of death for women in the United States. Mammography is one of the few preventive exams that tens of millions of women get regularly. That combination is what drove the bill’s sponsors.

The BAC reporting gap the law exposes

The law tells patients to ask about BAC. It doesn’t tell radiologists how to report it. No ACR BI-RADS category covers BAC, there’s no standard grading scale in the statute, and no guideline-based management threshold exists. Survey data show how much practice varies:

• In a 2020 survey of 598 radiologists, most said they mention BAC at least sometimes. Only about 41% said they report it always or most of the time.
• Among radiologists who do report BAC, a majority make no follow-up recommendation.
• In contrast, nearly 80% of surveyed ordering physicians said they would investigate coronary disease if BAC were reported. More than 60% wanted it in both the body and the impression of the report.

Some health systems have shown that consistent reporting is workable. Northwell Health began universal BAC reporting in early 2024. From January through October 2024, it reported BAC on about 88,000 mammograms, and 13.4% were BAC-positive. Radiologists there say the added reading time is minimal. In an earlier Northwell study, 57% of BAC-positive women who answered a 3-month follow-up survey after being notified said they had discussed the result with a primary care physician or cardiologist.

Not everyone supported the mandate. Two Johns Hopkins breast radiologists, including the division chief of breast imaging, opposed the bill. They cited the lack of a standardized way to measure BAC and of a defined clinical pathway. They also warned that universal notification could cause patient anxiety, lead to unnecessary testing, and pull attention away from breast cancer findings. MedChi (the Maryland State Medical Society) and the Maryland Section of ACOG supported it, as did the Maryland Radiological Society. Both sides make points worth building into your rollout.

Questions to settle now

• Does every letter need the notice? The text is conditional (“If your mammogram shows…”), and the statute doesn’t limit it to BAC-positive patients. A literal reading suggests it belongs in every screening results letter. Confirm your interpretation with counsel.
• What about the breast density notice? HB 1364 also adds the BAC paragraph to Maryland’s existing state density notice. That subsection doesn’t apply when federal MQSA rules require their own density notice, and the FDA’s national density requirement took effect September 10, 2024. In practice, the standalone BAC notice in new subsection (d) is the operative requirement. Keep your federally required density language as is.
• Diagnostic exams. The notice is tied to the screening results letter. Decide how you’ll handle BAC communication after diagnostic-only exams.

A rollout checklist for radiology leaders

1. Update letter templates. Add the statutory notice to every lay-letter template, including English, translated versions, and portal-delivered letters.
2. Standardize BAC reporting. Agree on whether and how BAC appears in the report. Build it into structured templates so it isn’t left to individual habit.
3. Evaluate quantification tools. FDA-cleared AI tools can detect and grade BAC automatically. They can reduce variation between readers and keep added workload low.
4. Define the hand-off. A patient-facing notice without a clinician-facing recommendation creates confusion. Work with primary care, OB/GYN, and cardiology partners on a simple, non-prescriptive pathway.
5. Prepare front-line staff. Schedulers, technologists, and patient navigators will get questions. Give them a short script that matches the statute: BAC is common, it’s a risk marker and not a diagnosis, and the next step is a conversation with your physician.
6. Close the loop. Track whether BAC-positive findings reach the referring provider and whether patients follow up. That’s the difference between meeting the notification requirement and actually improving outcomes.
7. Watch for regulations. The Department of Health may revise the notice as evidence changes. Assign someone to monitor for updates.

What comes next

State breast density laws followed a familiar pattern. One state acted, others followed, and a federal standard came last. BAC could follow the same path. Practices outside Maryland that standardize BAC reporting now will be ready if their state follows. They’ll also give referring physicians a useful cardiovascular signal from an exam patients are already getting.

Notification is the easy part. The value of HB 1364 depends on whether the finding reaches the right clinician and leads to a decision. Making sure incidental findings don’t fall through the cracks is the work Inflo Health was built for.

Sources

• Brown AL, Wahab RA, Zhang B, Smetherman DH, Mahoney MC. “Reporting and Perceptions of Breast Arterial Calcification on Mammography: A Survey of ACR Radiologists.” Academic Radiology 2022;29(Suppl 1):S192–S198. doi:10.1016/j.acra.2021.01.027.pubmed.ncbi.nlm.nih
• Maryland General Assembly, House Bill 1364 (2026), Chapter 604, enacted text, and Department of Legislative Services Fiscal and Policy Note (Third Reader – Revised).
• Nerlekar N, et al. “A novel breast arterial calcification age-based percentile nomogram for the incremental prediction of incidental cardiovascular events.” JACC: Cardiovascular Imaging, 2026. Via Diagnostic Imaging.
• McLenachan S, et al. “Breast arterial calcification on mammography and risk of coronary artery disease: a SCOT-HEART sub-study.” Clinical Radiology, 2019. PMC6512949.
• Parikh, N. I., Cacciabaudo, J. M., Singh, V. P., & Vincoff, N. S. (2025). Giving Women What They Want: Reporting Breast Arterial Calcification on Mammograms at Northwell Health System. JACC. Advances, 4(7), 101914. https://doi.org/10.1016/j.jacadv.2025.101914
• Telehealth.org, “Maryland Requires Breast Arterial Calcification Notice” (survey data, Northwell experience, stakeholder positions).
• AuntMinnie, “Maryland first state to consider BAC notification after mammogram.”
• U.S. FDA, MQSA final rule (national breast density notification, effective September 10, 2024).

This article is for general information and is not legal advice. Consult counsel about your organization’s compliance obligations.