Coronary computed tomography angiography (CCTA) has been the recommended first-line tool for investigating recent-onset chest pain since 2016. The impact on cardiovascular health has been significant. A 10-year trial following on from the SCOT-HEART study showed a 28 percent reduction in heart attacks in individuals who had a CCTA assessment.

Researchers estimate that CCTA has prevented around 6000 heart attacks nationwide over 10 years. Here, we will explore why CCTA is such a powerful tool for cardiovascular risk assessment and how recent advances in AI technology are providing even greater insights to guide patient care.

Why CCTA Matters for Cardiovascular Risk Assessment

The power of CCTA lies in the fact that it does not just show the channel through which blood flows to the heart muscle but also provides details on the coronary artery wall itself.

Most coronary artery disease (CAD) reports focus on artery narrowing (stenosis) as this explains angina and determines whether someone needs a stent. However, stenosis turns out to be a poor predictor of heart attacks.

What predicts cardiac events better is how much plaque there is and from what it is made.

Hard Plaque vs Soft Plaque

Calcified or hard plaque largely reflects old, healed, stable coronary artery disease — this is what is measured with a calcium score test.

Soft, fatty plaque poses a much greater risk as these plaques can rupture — this remains invisible on a calcium score test. This is why a calcium score of zero does not necessarily mean a low risk of cardiovascular events.

Mixed plaque contains both calcified plaque and soft plaque.

Around one in 10 people with a calcium score of zero have soft plaque. This is most prevalent in younger patients, smokers, and individuals with diabetes and/or familial hypercholesterolaemia, namely, people whose disease has not yet had time to calcify.

Calcium Scoring and Statins

To complicate matters further, statins to treat high cholesterol work partly by calcifying soft plaque to make it stable. A repeat calcium score test can, therefore, see an individual’s score rise despite their actual risk of a cardiovascular event decreasing.

This makes calcium scoring less than ideal for monitoring whether treatment is working, and can be challenging for patients to understand.

While calcium scoring can provide some reassurance and be helpful in risk stratification and discussions around preventive treatments, it does not provide the complete picture.

CCTA allows us to provide considerably more detail about a patient's coronary atherosclerotic plaques.

CCTA Plaque Analysis

Modern CCTA analysis measures the volume of each type of plaque, adjusted for the size of the artery.

In the SCOT-HEART study, patients with the most fatty plaque were around 5 times more likely to go on to have a heart attack. This was a stronger signal than suggested by their cardiovascular risk score, their calcium score or the degree of coronary artery narrowing.

Essentially, coronary artery narrowing explains today's symptoms, while plaque explains the following decade of cardiovascular health.

As a cardiac CT specialist, CCTA gives us the opportunity to move beyond describing a scan as simply ‘normal’ or ‘no significant stenosis.’ Instead, we can provide a more complete assessment of a patient's underlying atherosclerotic disease burden.

Recent advances allow us to take this a step further and provide insights on inflammation — a key contributor to cardiovascular risk.

Coronary Inflammation in Coronary Artery Disease

Coronary artery disease causes local inflammation as the body responds to changes in the coronary artery wall. When an artery wall becomes inflamed, it releases chemical signals into the fat immediately surrounding it. These signals change the character of that fat, which alters how the fat appears on a CT scan.

This change is visible on standard CCTA images. Advances in AI technology mean we can measure this change in the fat surrounding coronary arteries using existing CCTA images, with no need for extra scanning, radiation exposure or contrast.

How CaRi-HeartTM® Measures Inflammation

Caristo Diagnostics’ CaRi-Heart analysis tool examines inflammation-driven changes in pericoronary fat using AI.

Using existing images from a routine CCTA, it provides an indirect imaging biomarker of coronary inflammation. By measuring changes in how pericoronary fat appears on CCTA images, it provides a standardised, vessel-specific Fat Attenuation Index (FAI) Score™.

This is important as atherosclerosis is not simply a disease of plaque accumulation; it is also an inflammatory disease. Inflammation appears to be an important determinant of plaque instability and subsequent cardiovascular events. This association has been supported by a 2025 Scientific Statement from the American College of Cardiology (ACC).

The CRISP-CT study and Oxford Risk Factors And Non-invasive imaging (ORFAN) study, which support CaRi-Heart, demonstrated that an abnormal FAI provides prognostic information beyond conventional cardiovascular risk factors and anatomical assessment of coronary artery disease (CAD).

In ORFAN, FAI predicted cardiac mortality and major adverse cardiovascular events independently of cardiovascular risk factors and the presence or extent of CAD.

These insights tackle a limitation of conventional CCTA: 2 patients can have similar degrees of plaque or stenosis but very different underlying biological activity. Consequently, they can have potentially very different future risks.

While Cari-Heart analysis provides information on the underlying biological activity, Caristo Diagnostics’ second AI tool, Cari-PlaqueTM, offers greater depth of information on plaque burden.

How CaRi-Plaque Assesses Plaque Burden

CaRi-Plaque provides quantitative information about total plaque volume, calcified plaque, non-calcified plaque, low-density non-calcified plaque, plaque burden, stenosis and remodelling. This is valuable because 2 patients with the same degree of stenosis can have different amounts and types of underlying atherosclerosis.

For example, a moderate stenosis caused by a relatively stable, predominantly calcified plaque is biologically different from a similar stenosis associated with a substantial burden of soft or low-density plaque.

Detailed plaque analysis with CaRi-Plaque allows us to move from asking "how narrow is the artery?" to "how much atherosclerosis is present, and what type of atherosclerosis is it?".

This can improve our ability to identify patients who need particularly intensive preventive management and give patients a much clearer understanding of what their CCTA actually shows.

Where Does AI-Driven CCTA Analysis Fit In the Patient Care Pathway?

AI tools, such as Cari-Heart and Cari-Plaque, are important tools to support clinical decision-making by extracting more clinically useful information from existing scans.

They can provide additional quantitative information about plaque burden, composition and inflammation that may not be apparent from visual assessment alone.

These tools can also speed up the patient journey by automating time-consuming measurements needed for detailed CCTA analysis.

A cardiologist can then place these AI-derived measurements in the context of patient symptoms, risk factors, clinical history, and the quality and limitations of the CT examination.

In a primary care setting, the information could provide a more objective basis for discussions about lipid-lowering therapy, blood pressure control and broader cardiovascular prevention.

For cardiologists, it can help identify patients who warrant closer assessment or more aggressive risk-factor modification, including patients who have non-obstructive disease but evidence of a higher-risk phenotype.

Ultimately, the greatest opportunity lies in prevention: using the information from a CCTA not simply to exclude obstructive disease, but to identify and modify a patient's future cardiovascular risk.

How Can CaRi-Heart and CaRi-Plaque Support GPs

The additional information provided by Cari-Heart and Cari-Plaque can provide GPs with more targeted, clinically meaningful information.

For example, a GP referring a patient with chest pain could receive a report that does more than state whether there is obstructive coronary artery disease. The quantification of plaque burden, plaque composition and coronary inflammation can help communicate the patient's overall cardiovascular risk and disease phenotype.

Conversely, a patient with no significant stenosis but a low plaque burden and low inflammatory risk could be managed primarily through routine cardiovascular prevention, potentially avoiding unnecessary onward investigation.

For patients with substantial plaque burden, high-risk plaque characteristics or increased coronary inflammation, the information could support earlier cardiology review and more intensive preventive management.

AI-driven CCTA analysis can, therefore, be used as a preventive cardiovascular test to improve patient care, rather than simply a test for ruling in or ruling out obstructive coronary artery disease.

Explore Enhanced CCTA with Caristo Reporting

If you are curious to learn more about how AI analysis of your patient’s CCTA images could help manage their cardiovascular health, take a look at our CaRi-Heart and CaRi-Plaque Guide for Healthcare Professionals.

If you are ready to refer a patient for CCTA with CaRi-Heart, CaRi-Plaque or both, get started on your referral with Vista Health, your local Caristo Diagnostics partner.