Coronary computed tomography angiography (CCTA) is an effective imaging modality increasingly accepted as a firstline test to diagnose coronary artery disease (CAD). CCTA stands out among other diagnostic modalities with an ability to image various stages of atherosclerosis, including plaque progression and rupture. Plaque burden and characteristics by CCTA have been shown to have prognostic implications for patient management (1). Also, detecting early subclinical CAD may allow for interventions aimed at preventing the progression of coronary plaque and reducing coronary events (2). The aim of this article is to discuss the innovative tools derived from CCTA using artificial intelligence (AI) which would aid in risk stratification and medical decision making for patients with CAD. For many observers, machine learning is treated as a "black box" in which data are analyzed and results produced, without attempting to understand how or why. This has the potential to cause significant issues if systematic biases are introduced and not recognized.
Automated plaque characterization software and detecting culprit lesionsAI has been used to develop deep convolutional neural networks (CNN) to classify CCTA in the correct Coronary Artery Disease Reporting and Data System (CAD-RADS) category and this was shown to be accurate and less timeconsuming (3). Some of the emerging technologies which use histologically validated, application-based tissue quantification to characterize atherosclerosis include the commercial software applications vascuCAP (Elucid Bioimaging, Boston, Massachusetts, USA) and Sureplaque TM (V7.5; Vital Images, MN, USA).Sureplaque TM software: SUREPlaque software (V7.5; Vital Images, MN, USA) uses color defined Hounsfield unit (HU) ranges to define plaque characteristics (Figure 1). The software is based on curved multiplanar reconstructions. It has shown good correlation to the morphometric parameters of atheroma, but fair correlation with regard to the relative plaque composition (4-6).vascuCAP TM software: model-based quantification algorithms, as used by vascuCAP, aim to reduce interscan and interobserver variability and allow for detailed characterization of morphological features including positive remodeling, lipid-rich necrotic core, and coronary artery plaque burden (7,8). van Assen et al. retrospectively studied 45 patients with suspected CAD of which 16 (36%) experienced major adverse cardiac events within 12 months. The software was used to evaluate lumen area, wall area, stenosis percentage, wall thickness, plaque burden, remodeling ratio, calcified area, lipid rich necrotic core area and matrix area. Regression analysis using clinical risk factors resulted in a prognostic accuracy of 63% with a corresponding area under the curve (AUC) of 0.587. The use of morphologic features alone resulted in an increased accuracy of 77% with an AUC of 0.94. Combining both clinical risk factors and morphological features in a multivariate logistic regression analysis increased the accuracy to 87% with a sim...