The Intersection of Cardiovascular Imaging and Prevention

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One of the underlying premises of cardiovascular imaging is to improve health outcomes by diagnosing various forms of cardiac and vascular disease. As our diagnostic capabilities have improved, it is now possible to diagnose disease with increased precision and at earlier stages. However, in many instances in medicine, it is not always clear if earlier detection of disease can lead to improved outcomes and if the use of imaging to detect such “preclinical” disease is cost-effective. However, when it comes to cardiovascular disease, decades of research have shown that there is a wide array of highly effective lifestyle and pharmacologic therapies that can have a significant impact on lowering the risk of cardiovascular events. Nevertheless, such therapies are drastically underutilized, in part due to a wide gap in the awareness and treatment of various underlying risk factors.

So, the question that arises is: How can we use imaging to enhance cardiovascular disease prevention—which is, after all, the number one killer of men and women in the United States? There are many opportunities where imaging can make a difference. The identification of coronary atherosclerosis can lead to enhanced risk assessment and more appropriate allocation of preventive therapies (1). Furthermore, imaging can also be used in clinical trial design (2) or in studies aimed at elucidating the mechanistic insights of various therapies (3). Yet, despite the many promising applications of cardiovascular imaging in prevention, there is a need to make cardiovascular imaging more scalable by making it more widely available and simpler to use. One opportunity for accomplishing this is to evaluate and report cardiac findings when imaging studies are acquired for noncardiac indications. Additional opportunities include advances in image acquisition and analysis and expansion of the scientific evidence linking various imaging biomarkers with effective therapies. Given the interest and importance of this area, in this special focus issue of Radiology: Cardiothoracic Imaging (RCTI), we offer several articles that provide further insights on how imaging can be used to enhance cardiovascular disease prevention.

Undoubtedly, one of the most powerful imaging tests in preventive cardiology is the coronary artery calcium (CAC) scan. Indeed, this is the only imaging testing that is endorsed by the current cholesterol and prevention guidelines. This current special focus issue has a contemporary review by Adelhoefer and colleagues from the Johns Hopkins Ciccarone Center for Prevention of Cardiovascular Disease on new insights regarding CAC testing (4). This article summarizes important recent advances from the CAC Consortium, an observational cohort study of 66 636 asymptomatic individuals who were free from cardiovascular disease at baseline. Specifically, the CAC Consortium was able to evaluate the impact of CAC testing among various subgroups, such as young individuals, ethnic minorities, smokers, and individuals with various other underlying risk factors. When it comes to distribution of CAC, the CAC Consortium has demonstrated that the presence of CAC in the left main is associated with higher risk, even after adjusting for the fact that such individuals often have higher and more extensive CAC. The CAC Consortium also further confirmed the low event rate associated with a CAC score of zero, and on the other end of the spectrum, the markedly increased risk associated with high CAC, especially when CAC is greater than 1000. The implications of these findings are that patients with very high CAC are more likely to benefit from early and aggressive pharmacotherapy, which in 2021 translates into numerous other potential agents beyond just lipid-lowering therapies.

Further building on applying CAC data to cardiovascular disease prevention, Obisesan and colleagues provide us with a timely update on CAC interpretation for both chest and cardiac CT studies (5). Their article provides important advice on what type of information to report on CAC testing, as well as the differences between absolute and percentile scores. They also provide an overview of different methods to visually estimate CAC based on chest CT studies, a topic which is of particular importance to thoracic radiologists.

An intriguing question in preventing coronary heart disease is whether we can identify at-risk individuals before they even develop coronary plaque. One promising technique in this regard is to identify coronary inflammation by evaluating for changes in the perivascular adipose tissue. Klüner and colleagues from Oxford University have helped pioneer this technique and now provide us with a contemporary overview of the latest evidence underlying the fat attenuation index (FAI), a novel imaging biomarker that can be used to detect coronary inflammation (6). This review outlines the potential future role of integrating the FAI to enhance primary and secondary prevention among individuals undergoing coronary CTA. Ongoing studies will further evaluate the prognostic capabilities of FAI as well determine if treatment based on this signal may lead to improved outcomes.

When considering the future role of imaging in prevention, it is imperative to understand the capabilities and future implications of artificial intelligence (AI) and machine learning. To that end, the current issue also provides a superb overview of AI in cardiovascular imaging for risk stratification in coronary artery disease (7). Lin and colleagues provide an insightful overview that covers how machine learning applied to cardiac CT and nuclear cardiology imaging can quantify CAC, quantify epicardial fat, identify lesion specific ischemia, identify obstructive coronary artery disease, and enhance risk assessment. The authors thoughtfully discuss challenges to AI implementation, while offering a vision where AI can improve our ability to quantify various imaging findings, while also computing comprehensive risk scores which deliver real-time prognostic data.

Collectively, the articles which are included in our special RCTI cardiovascular disease prevention issue and on our disease prevention collection page (https://pubs.rsna.org/page/cardiothoracic/cvdprevention) offer practical and actionable information which will be relevant for current practice, as well as an outlook on some of the emerging techniques which are currently being developed. A common theme to these techniques is that imaging provides a more personalized and more precise approach to risk assessment, and one which can have direct implications on patient management. This special focus issue underscores that the intersection of imaging and prevention is an exciting place to be! After all, it is where technology, imaging science, preventive clinical care, lifestyle medicine, personalized medicine, implementation science, and economics all align in the hopes of improving patient outcomes.

Disclosures of Conflicts of Interest: R.B. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: research support from Amgen; associate editor for Radiology: Cardiothoracic Imaging; guest editor for this issue. Other relationships: disclosed no relevant relationships. S.A. Activities related to the present article: disclosed no relevant relationships. Activities not related to the present article: author receives royalties from Elsevier for textbook authoring; Editor for Radiology: Cardiothoracic Imaging. Other relationships: disclosed no relevant relationships.