Why Agatston-2.0 Matters

Traditional coronary artery calcium scoring, now referred to as Agatston-1.0, relies on technical assumptions established in the late 1980s and early 1990s, including a fixed 130-Hounsfield-unit threshold and conventional 2.5-3 mm CT slice thickness. These parameters made the method practical and reproducible, but they can also miss very small, low-density, fragmented, or partially calcified coronary plaques.

 

Agatston-2.0 was developed to address these limitations. Instead of relying only on rigid thresholds, it uses AI-based coronary segmentation and continuous voxel-wise calcium quantification. The result is a more sensitive and biologically faithful way to quantify coronary calcium, especially early or low-burden disease that may be invisible to conventional scoring.

 

"This is quantitative CT doing what it should do," said David F. Yankelevitz, MD, Department of Diagnostic, Molecular, and Interventional Radiology, Icahn School of Medicine at Mount Sinai. "Agatston-2.0 extracts more useful signal from the scan."

 

The advance is important because CAC scanning is already widely used in clinical prevention. Agatston-2.0 does not require an invasive test or a new imaging philosophy. It builds directly on the established value of CAC scoring and updates the measurement to match the capabilities of contemporary CT and AI.

 

Answering the "Soft Plaque" Criticism of CAC

One of the most persistent criticisms of CAC scanning is that non-contrast calcium scans may miss so-called soft or non-calcified plaque. That criticism is partly true but often oversimplified. A CAC scan is not a coronary CT angiogram and is not intended to characterize the coronary lumen, stenosis, or purely non-calcified plaque morphology. However, coronary atherosclerosis exists along a continuum, and many plaques described as soft, non-calcified, or CAC-negative may contain subtle, low-density, fragmented, or semi-calcified components that fall below the detection rules of Agatston-1.0.

 

This is one of the key problems Agatston-2.0 addresses. By replacing a binary threshold with continuous AI-derived calcium probability, spatial neighborhood analysis, and automated coronary segmentation, Agatston-2.0 can detect subthreshold calcium signal that older scoring rules may miss. In practical terms, some risk previously attributed to "CAC-negative soft plaque" may actually reflect semi-calcified disease that was present but not counted by the original scoring method.

 

"The soft-plaque argument against CAC has often been overstated," said Dr. Naghavi. "Agatston-2.0 shows that part of the blind spot may be outdated scoring, not CAC imaging itself."

 

This distinction is clinically important. Agatston-2.0 does not replace CCTA when the clinical question is plaque morphology or stenosis. But it strengthens the scientific foundation of CAC scanning by narrowing a commonly cited gap: the inability of conventional scoring to capture subtle, early, or semi-calcified coronary plaque signal.

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Refining the “Power of Zero”

A CAC score of zero has long been one of the most reassuring findings in preventive cardiology. This concept, widely known as the "Power of Zero," reflects the very low near-term risk seen in many patients with no detectable coronary calcium by conventional scoring.

 

However, a small but clinically important number of patients with CAC=0 still experience coronary heart disease events. The newly published study directly addresses this unresolved question: can modern AI detect hidden coronary calcium signal in some patients whose traditional Agatston score is zero?

 

The answer appears to be yes.

 

In the study, investigators pooled 3,965 participants with CAC=0 from two major prospective cohorts: the Multi-Ethnic Study of Atherosclerosis and the Framingham Heart Study. Agatston-2.0 detected AI-derived coronary calcium in 862 participants, representing 21.7% of individuals who were classified as CAC=0 by conventional scoring.

 

Those with AI-CAC greater than zero had significantly higher long-term coronary heart disease risk than those with AI-CAC of zero. Over 20 years, coronary heart disease incidence was 7.7% in participants with AI-CAC greater than zero compared with 3.8% in those with AI-CAC of zero. After adjustment for traditional cardiovascular risk factors, AI-CAC greater than zero remained independently associated with incident coronary heart disease.

 

Agatston-2.0 also predicted future conversion from CAC=0 to a positive traditional CAC score on repeat CT imaging, suggesting that the AI-detected signal represents clinically meaningful early coronary calcification rather than random image noise.

 

"The Power of Zero remains powerful and is even more powerful with Agatston-2.0," said Nathan D. Wong, PhD, Heart Disease Prevention Program, Mary and Steve Wen Cardiovascular Division, University of California Irvine. "Agatston-2.0 helps identify which zero is truly zero as well as those with possible earlier, semi-calcified disease associated with greater future risk than those previously thought to be 0 based on traditional Agatston scoring."

 

"A more precise zero can help clinicians refine prevention," said Robert A. Kloner, MD, PhD, Huntington Medical Research Institutes and Keck School of Medicine of the University of Southern California. "That is the clinical value of this advance."