Combined anatomical and functional evaluation of coronary artery disease (CAD) using computed tomography (CT) has recently emerged as an accurate, robust, and non-invasive tool for the evaluation of ischemic heart disease. Cardiac CT has become a one-stop-shop imaging modality that allows the simultaneous depiction, characterization, and quantification of coronary atherosclerosis and the assessment of myocardial ischemia. Advancements in scanner technology (improvements in spatial and temporal resolution, dual-energy imaging, wide detector panels) and the implementation of iterative reconstruction algorithms enables the detection of myocardial ischemia in both qualitative and quantitative fashion using low-dose scanning protocols. The addition of CT perfusion (CTP) to standard coronary CT angiography is a reliable tool to improve diagnostic accuracy. CTP using static first-pass imaging enables qualitative assessment of the myocardial tissue, whereas dynamic perfusion imaging can also provide quantitative information on myocardial blood flow. Myocardial tissue assessment by CTP holds the potential to refine risk in stable chest pain or microvascular dysfunction. CTP can aid the detection of residual ischemia after coronary intervention. Comprehensive evaluation of CAD using CTP might therefore improve the selection of patients for aggressive secondary prevention therapy or coronary revascularization with high diagnostic certainty. In addition, prognostic information provided by perfusion CT imaging could improve patient outcomes by quantifying the ischemic burden of the left ventricle. The current review focuses on the clinical value of myocardial perfusion imaging by CT, current status of CTP imaging and the use of myocardial CTP in various patient populations for the diagnosis of ischemic heart disease.
In recent years, coronary computed tomography angiography (CCTA) has emerged as an accurate and safe non-invasive imaging modality in terms of detecting and excluding coronary artery disease (CAD). In the latest European Society of Cardiology Guidelines CCTA received Class I recommendation for the evaluation of patients with stable chest pain with low to intermediate clinical likelihood of CAD. Despite its high negative predictive value, the diagnostic performance of CCTA is limited by the relatively low specificity, especially in patients with heavily calcified lesions. The discrepancy between the degree of stenosis and ischemia is well established based on both invasive and non-invasive tests. The rapid evolution of computational flow dynamics has allowed the simulation of CCTA derived fractional flow reserve (FFR-CT), which improves specificity by combining anatomic and functional information regarding coronary atherosclerosis. FFR-CT has been extensively validated against invasively measured FFR as the reference standard. Due to recent technological advancements FFR-CT values can also be calculated locally, without offsite processing. Wall shear stress (WSS) and axial plaque stress (APS) are additional key hemodynamic elements of atherosclerotic plaque characteristics, which can also be measured using CCTA images. Current evidence suggests that WSS and APS are important hemodynamic features of adverse coronary plaques. CCTA based hemodynamic calculations could therefore improve prognostication and the management of patients with stable CAD.
To assess the prevalence of incidental extracardiac findings in patients who underwent cardiac CT for the evaluation of left atrial (LA) anatomy before atrial fibrillation (AF) catheter ablation. We also aimed to determine the independent predictors of relevant extracardiac alterations.
Patients and methods
We studied consecutive patients who underwent cardiac CT with a 256-slice scanner for the visualization of LA anatomy before AF ablation. Prevalence of clinically significant and not significant extracardiac findings were recorded. Moreover, we determined the variables associated with relevant extracardiac alterations with uni- and multivariate logistic regression analyses.
In total, 1,952 consecutive patients who underwent cardiac CT examination between 2010 and 2020 were included in our study (mean age 61.2 ± 10.6 years; 66.2% male). Incidental extracardiac findings were detected in 820 (42.0%; 95%CI = 0.40–0.44%) patients, while clinically significant alterations were reported in 416 (21.3%; 95%CI = 20.0–23.2%) patients. When analyzing the predictors of clinically relevant alterations, age (OR = 1.04; 95%CI = 1.03–1.05), male sex (OR = 1.39; 95%CI = 1.12–1.73), chest pain (OR = 1.46; 95%CI = 1.09–1.93), hypertension (OR = 1.42; 95%CI = 1.12–1.81), heart failure (OR = 1.68; 95%CI = 1.09–2.53), obstructive CAD (OR = 1.56; 95%CI = 1.16–2.09) and prior stroke/TIA (OR = 1.56; 95%CI = 1.04–2.30) showed association with clinically significant incidental findings in the univariate analysis (all P < 0.05). In the multivariate analysis, age (OR = 1.04; 95%CI = 1.02–1.06; P < 0.001) proved to be the only significant predictor of clinically relevant extracardiac finding.
Cardiac CT performed before AF ablation is not only helpful in understanding LA anatomy, but might also identify clinically significant pathologies. These incidental findings might have further diagnostic or therapeutic consequences.