EACVI Best of Imaging: Advances in Cardiac CT

by | Jan 11, 2021 | All News, Blog

As a global developer of AI-enabled software medical devices, our team closely follows advances in cardiac computed tomography (CT). In December 2020, the European Association of Cardiovascular Imaging (EACVI), a subspecialty community of the European Society of Cardiology (ESC), hosted the first Best of Imaging conference that highlighted recent developments in cardiovascular imaging.

In this post, we summarize what we consider to be the “best of” the EACVI – Best of Imaging conference presentations related to cardiac CT covering primary prevention, atherosclerotic plaque imaging, and artificial intelligence (AI).

CT in Evaluating Coronary Plaque

Dr. Pál Maurovich-Horvat, Associate Professor of Cardiology and Radiology & Director of the Cardiovascular Imaging Research Group at Semmelweis University, examined the role of CT in plaque imaging in the presentation “Imaging Plaque versus Imaging Perfusion.”

Dr. Maurovich-Horvat emphasized the value of CT as a non-invasive imaging modality for plaque imaging, recounting the results of the SCOT-HEART[1] trial and the CREDENCE[2] trial. The SCOT Heart trial demonstrated that patients with low-attenuation non-calcified plaque burden were nearly five times more likely to have subsequent myocardial infarction compared to patients with low plaque burden, outperforming cardiovascular risk factors. This outperformed traditional cardiovascular risk factors, luminal stenosis severity, CT calcium scoring, and total plaque burden. As Dr. Maurovich-Horvat explained, this study shows that imaging plaque is associated with improved outcomes.

The CREDENCE trial compared the diagnostic accuracy of comprehensive anatomic versus functional imaging measures for estimating vessel-specific FFR. In the trial, patients underwent invasive coronary angiography with measurement of invasive FFR, CCTA quantification of atherosclerotic plaque and CT-FFR, and semiquantitative scoring of rest/stress myocardial perfusion imaging. The CREDENCE trial demonstrated that quantification of obstructive and non-obstructive atherosclerotic plaque was superior to functional imaging in the diagnosis of invasive FFR. When the investigator added plaque features and plaque quantity, the AUC increased when compared to stenosis severity metrics.

Dr. Maurovich-Horvat continued that CT could be used as a “one-stop-shop” for imaging coronary artery disease by combining plaque burden with adverse plaque features, functional information from CT-FFR, and myocardial perfusion imaging techniques. However, Dr. Maurovich-Horvat reminded the audience that CT is not suitable for all patients. For patients with renal insufficiency, extensive coronary calcifications, post revascularization, known coronary disease, and morbid obesity, CT is not advised. In cases such as this, perfusion imaging may provide more useful information.

CT in Primary Prevention of Cardiovascular Disease

Dr. Leslee J. Shaw, Professor & Endowed Chair at Weill Cornell Medical College, advocated for the value of CT in guiding primary prevention in the session “Controversies in Computed Tomography.” Dr. Shaw began the session debate by speaking to the challenges with using risk factors at the patient level, explaining that atherosclerotic cardiovascular risk scores are meant for estimating population risk and thus, they largely overestimate risk in patients who are under 75 years of age.

Dr. Shaw expanded on the challenges with risk factors, stating “You can use risk scores as guides, but not necessarily as a precise measure of what is happening with the patient in front of you.” Because risk factors were developed to be used on populations, when you translate that to the individual patient, risk factors lose their precision even when they are validated. Dr. Shaw shared that an imaging marker, such as calcified plaque, can instead provide a better association with risk when compared to a risk factor. Imaging the disease pathway can offer improvements in assessing risk. Dr. Shaw focused on CT detection of calcified plaque, explaining that coronary calcium scoring is safe, low cost, easy to measure, and can improve risk stratification.

Multiple randomized trials, including NHLBI Multi-Ethnic Study of Atherosclerosis (MESA): Coronary Artery Calcium (CAC) & 12-year ASCVD[3], have demonstrated a strong association with improved outcomes. Data from the EISNER trial suggest that CAC scoring can improve patient adherence. According to Dr. Shaw, the evidence from these randomized trials supports CAC-guiding to improve adherence to preventative care.

AI in Cardiovascular Imaging

AI can add value in cardiovascular imaging, non-invasively calculating fractional flow reserve (FFR) from coronary CT angiogram scans, and detecting and classifying plaque.

Dr. Filippo Cademartiri, Chairman of the Department of Radiology at Asur Marche & Associate Professor of Radiology at Erasmus Medical Center University, described the growing role of AI in cardiovascular imaging from a physician’s perspective in the presentation “Artificial Intelligence in (Cardiac) Computed Tomography.”

Dr. Cademartiri explained that AI has shifted from being a trendy topic published in major journals to playing a valuable role in clinical practice. Dr. Cademartiri referenced the common saying that “AI will replace radiologists,” posing instead that “radiologists who use AI will replace those who do not.” Rather than ignoring AI, he advised radiologists to develop an understanding of what AI is and how it works.
As AI solutions become more widely available in clinical practice, the solutions will likely do part of the jobs of cardiologists and radiologists and speed the workflow. In preparation for the increasing role of AI increasing clinical practice, Dr. Cademartiri emphasized the importance of proper validation of algorithms and clinician education to effectively move forward.

The Future of Cardiac CT

The recent developments in cardiac imaging are helping to drive toward a more patient-centric, multi-modality approach to the early diagnosis and treatment of patients with cardiovascular diseases.
As we transition to a new year, advocacy for the role of CT as a first-line diagnostic test for patients with coronary artery disease can help guide cardiovascular imaging toward improved care paradigms that improve clinical outcomes.

References
[1] Newby, David & Williams, Michelle & Hunter, Amanda & Pawade, Tania & Shah, Anoop & Flapan, Andrew & Forbes, John & Hargreaves, Allister & Leslie, Stephen & Lewis, Steff & Mckillop, Graham & Mclean, Scott & Reid, John & Spratt, James & Uren, Neal & Steering, Trial & Timmis, Adam & Berry, Colin & Steedman, Tracey. (2015). CT coronary angiography in patients with suspected angina due to coronary heart disease (SCOT-HEART): An open-label, parallel-group multicentre trial. The Lancet. 385. 10.1016/S0140-6736(15)60291-4.

[2] Rizvi A, Hartaigh BÓ, Knaapen P, Leipsic J, Shaw LJ, Andreini D, Pontone G, Raman S, Khan MA, Ridner M, Nabi F, Gimelli A, Jang J, Cole J, Nakazato R, Zarins C, Han D, Lee JH, Szymonifika J, Gomez MJ, Truong QA, Chang HJ, Lin FY, Min JK. Rationale and Design of the CREDENCE Trial: computed TomogRaphic evaluation of atherosclerotic DEtermiNants of myocardial IsChEmia. BMC Cardiovasc Disord. 2016 Oct 6;16(1):190. doi: 10.1186/s12872-016-0360-x. PMID: 27716131; PMCID: PMC5053174.

[3] Osawa, K., Nakanishi, R., & Budoff, M. (2016). Coronary Artery Calcification. Global heart, 11(3), 287–293. https://doi.org/10.1016/j.gheart.2016.08.001