There is a growing body of evidence that epicardial adipose tissue (EAT) plays an enhancing role in the development of coronary atherosclerosis. 1,2 Pericardial fat is deposited around the heart at two locations, as epicardial and paracardial adipose tissue separated from each other by the parietal pericardium. Paracardial adipose tissue originates from the primitive thoracic mesenchyme and is supplied by the pericardiophrenic artery, a branch of the internal thoracic artery. EAT is defined as adipose tissue situated within the pericardium. EAT originates from the splanchnopleuric mesoderm (such as the mesenteric and omental fat deposits), and the vascular supply is from coronary arteries. Conceptually, EAT is more interesting than paracardial adipose tissue because of the close anatomic relationship between EAT and the myocardium. EAT also includes pericoronary fat situated around the coronary arteries, which may even be more appealing due to its very close proximity to the coronary arteries, suggesting a role for the development of coronary atherosclerosis. So far there is no general consensus as to which of these fat deposits should be studied, but most reports are about EAT, and few also report about the peri-coronary fat deposits. 1,2 EAT is metabolically active visceral fat, and the quantity of EAT is correlated with the metabolic syndrome (a waist circumference, hypertriglyceridemia, and hyperglycemia), cardio-metabolic risk factors, and coronary atherosclerosis. 2 EAT is distributed asymmetrically around the heart, and the fat is deposited mainly at the atrioventricular and interventricular grooves, around the major coronary arteries and free wall of the right ventricle, and the apex of the left ventricle. EAT can be measured by magnetic resonance imaging or echocardiography, but recently computed tomography (CT) has emerged as a robust, 3-dimensional, high-resolution imaging technique that reliably identifies EAT. CT allows quantification of EAT by manually tracing the pericardium on cross-sectional CT images. Within the traced region, the adipose tissue is identified by voxels that have a range of −190 to −30 HU. Automated computer-assisted methods allow quantification of epicardial fat tissue measurements.The measurements are presented as regional fat thickness (mm), as cross-sectional area (cm 2 ), and as a volume (cm 3 ). EAT volume is reported as ranging from 68 toThe author has no funding, financial relationships, or conflicts of interest to disclose. 124 cm 3 . The volume of EAT accounts for approximately 15% to 20% of the total cardiac volume and covers approximately 80% of the total cardiac surface. EAT accounts for roughly 1% of the total body fat mass. EAT volume is higher in patients with a high body mass index (BMI) than in patients with a low BMI. The mean EAT thickness measured at several sites, including the free right ventricular wall, left ventricular anterior wall, and grooves was 5.3 ± 1.6 mm. 1 The measurement of regional fat thickness around the coronary arteries is useful because ...