Hidden Insights: How Routine Scans Can Reveal Unexpected Health Risks

Millions of CT scans are performed each year, often to diagnose conditions like pneumonia or rule out serious illness. But increasingly, clinicians are recognizing that these scans contain a wealth of information beyond the initial question they were ordered to answer – data that could reveal hidden risks for heart disease, osteoporosis, and even cancer. The potential to proactively identify these conditions, rather than discovering them later during a crisis, is gaining momentum, though challenges remain in consistently capturing and utilizing this “incidental” data.

Data Hiding in Plain Sight

A single chest CT produces hundreds of cross-sectional images, offering a detailed look inside the body. A trained radiologist – or, increasingly, sophisticated algorithms – can analyze these images to detect calcium buildup in coronary arteries, assess muscle mass, estimate bone density, and identify early changes in the liver. None of this requires additional scans or radiation exposure; the information is already present. This concept, known as opportunistic screening, aims to leverage existing imaging to identify other health risks simultaneously.

Uncovering Coronary Artery Calcium

Perhaps the most compelling example of opportunistic screening is the detection of coronary artery calcium (CAC). Calcium deposits in the coronary arteries indicate underlying atherosclerosis, the process that leads to most heart attacks. CAC scoring is a strong predictor of future cardiac events, offering predictive value beyond traditional risk assessments.

While dedicated cardiac CT scans are used to precisely measure CAC, the information is often visible on standard chest CTs performed for other reasons. Studies have shown that CAC measurements from lung screening CTs closely align with those from dedicated cardiac scans, demonstrating the potential for identifying cardiac risk even when it wasn’t the primary focus of the scan. Approximately 19 million noncardiac chest CTs are performed annually in the United States, each offering this potential for incidental cardiac assessment. However, research indicates that radiologists report CAC in less than half of cases where it is present.

Beyond the Heart: Additional Findings

The benefits of opportunistic screening extend beyond cardiovascular health. CT scans can also provide insights into muscle mass, bone density, and liver health. Measurements of muscle loss (sarcopenia) are linked to higher rates of postoperative complications and mortality. Bone density assessments from CT scans can predict fracture risk, and liver fat visible on CT can signal early metabolic disease. These findings are all present in scans already being performed, at minimal additional cost.

Interestingly, research at Indiana University studying nearly 15,000 patients undergoing dedicated cardiac calcium scans revealed that roughly one in four were potentially eligible for lung cancer screening, yet fewer than 11% had ever been screened. This highlights the overlap between risk factors for heart disease and lung cancer, and the current gaps in proactive screening for both conditions.

The Broader Context: Lung Cancer Screening and Cardiovascular Risk

The scale of this missed opportunity is further underscored by the National Lung Screening Trial, which established low-dose CT as an effective lung cancer screening tool. Surprisingly, the most common cause of death among trial participants wasn’t lung cancer, but rather cardiovascular disease. More participants died of heart attacks than from the cancer the trial was designed to detect.

What Can You Do?

While health systems work to improve data capture and utilization, there are steps patients can grab. If you are undergoing a CT scan, discuss with your doctor whether the scan might reveal information relevant to your overall health. If you are between 50 and 80 with a significant smoking history, discuss lung cancer screening with your doctor; currently, only about 1 in 5 eligible patients are being screened.

The potential to unlock valuable health insights from existing medical imaging is significant. By embracing opportunistic screening, we can move towards a more proactive and comprehensive approach to patient care, utilizing the data already at our fingertips.