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Incidental findings on a calcium score scan

The same CT can show something outside the coronary arteries. The rates in published series are not a prediction for you.

A coronary calcium scan is ordered to look at the heart arteries. The pictures are still a CT of part of the chest, so they include pieces of the lungs, the chest wall, and the upper abdomen. A reader can notice something there that nobody was looking for. That is an incidental finding. It is not part of the Agatston score, and it is not a result you diagnose from a webpage.

Nobody has medically reviewed this page. CalciumCT.com is a directory of published cash prices. We do not perform scans, read scans, employ clinicians, or practice medicine in any state. A finding outside the arteries is a question for the clinician who ordered the scan, not a label you apply to yourself. How our guides are written.

Why the finding is discussed at all

The U.S. Preventive Services Task Force, weighing whether to add a calcium score to routine risk assessment in adults without symptoms, called the evidence insufficient in 2018. Among the harms it named were radiation and incidental findings on the CT (Curry SJ, et al., JAMA, 2018). The task force did not publish a rate, and it did not say the findings are usually serious. It listed them as a harm because a scan done for one question can start a chain of further tests for another.

How often that happens depends on who was scanned, what scanner was used, and how hard the readers looked. Two studies get cited as if they were one national rate. They are not.

One center, an electron-beam scanner, 2001

Horton and colleagues counted extracardiac findings on coronary calcium screening exams at one center (Circulation, 2002). Between 1 January and 1 October 2001, 1,326 consecutive patients had the exam on an electron-beam CT scanner. Two board-certified radiologists read each exam on a workstation, using mediastinal, lung, and bone windows, not the heart images alone.

They called 103 of the 1,326 exams positive for a significant extracardiac finding that, in their judgment, needed clinical or imaging follow-up. That is 7.8%. The breakdown they published was:

The authors’ conclusion was that a radiologist should read the whole examination. That conclusion is about how the scan is read. It is not a prediction that 8% of people who book a calcium score in 2026 will need a work-up. The scanner was an electron-beam machine, the window was nine months at one center, and “significant” was the definition those readers used. Today’s multidetector scanners, and today’s rules for which lung nodules are followed, are different. Quoting 7.8% as the current rate leaves those differences out.

A later series, and only in people with diabetes

A 2021 paper in PLOS One counted incidental findings on calcium-score CTs in a different population (Gaudillière M, et al.). The group was 732 consecutive asymptomatic patients with diabetes — 187 with type 1, 482 with type 2, and 63 with type 3 — scanned between 2015 and 2017. Their mean age was about 61.

Incidental findings were recorded in 117 of the 732 patients, which is 16.0%. Of those 117, 105 were previously unknown. Lung abnormalities accounted for 76 patients, and 31 of those were pulmonary nodules. The other findings the paper lists, each in a small share of the whole group, were pericardial, vascular, thymic, and digestive. Findings were more common in type 2 and type 3 diabetes than in type 1. In a multivariate analysis, microalbuminuria, the type of diabetes, and smoking were associated with having a finding.

Ten patients, 9.3% of those with a finding, had the finding lead to treatment of the underlying condition. The paper does not say the other findings were harmless, and it does not say they were emergencies. It says a fraction were treatable, in this diabetic cohort.

Sixteen percent is not a correction of Horton’s 7.8%. The patients had diabetes, the years were 2015–2017, and the scanner was a multidetector CT. People without diabetes are not in the denominator. Using either percentage as “the chance your scan will find something” treats a single series as a forecast. Neither paper is that forecast.

What to do with a sentence on the report

If your report mentions a nodule, a liver lesion, or any other finding outside the arteries, contact the clinician who ordered the scan and ask what follow-up, if any, they want. Do not decide from the size alone that a nodule can wait, and do not decide from a webpage that it cannot. Nodule follow-up depends on size, appearance, your history, and the protocol the reading group uses. Those details are on the report and in the conversation, not here.

A finding can also be absent from a report that was read only for the calcium score. Horton’s point was that the rest of the pictures deserve a read. If you have the images and a question about something you think you see, that question goes to a clinician, not to a second look you do yourself.

The calcium result is a separate line on the same report. What an Agatston score describes is on our score guide. The visit itself — prep, time, and radiation — is on what to expect. Calcium mentioned on a CT that was not a calcium-score appointment is a different exam.

The dedicated noncontrast score, when that is the exam that was ordered, is billed as CPT 75571. An incidental finding does not change that code, and it can lead to further imaging that is billed separately. Ask the facility what was ordered before you treat the appointment as a single price.

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Sources

All sources accessed 13 October 2026.

This is general education, not medical advice, and no clinician has reviewed it. Do not ignore a nodule, and do not diagnose one from this page. Follow-up belongs to the clinician who has the report.

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