Epicardial adipose tissue imaging as a cardiometabolic biomarker in diabetes: from pathophysiology to clinical translation

Epicardial adipose tissue (EAT) is a metabolically active visceral fat depot located between the myocardium and the visceral pericardium. Its anatomical proximity to the heart allows local interactions with the coronary arteries and myocardium. In type 2 diabetes mellitus (T2DM), EAT expansion and altered inflammatory signaling have been associated with coronary atherosclerosis, myocardial remodeling, and arrhythmias. Computed tomography (CT) and cardiovascular magnetic resonance (CMR) allow non-invasive assessment of EAT volume and composition. Global EAT volume and mean CT attenuation describe the whole depot, whereas the pericoronary fat attenuation index provides a local, vessel-centered measure associated with coronary inflammation. CMR complements these measurements with fat–water separation, myocardial tissue characterization, and perfusion assessment. Echocardiography provides an accessible measure of thickness, while positron emission tomography/CT offers research-level assessment of metabolic activity. Lifestyle interventions and some glucose-lowering therapies reduce EAT burden. However, parallel improvements in EAT and cardiovascular measures do not establish that EAT reduction mediates clinical benefit. EAT imaging is not yet a validated basis for treatment selection or a surrogate for cardiovascular outcomes. This narrative review examines the biological and imaging evidence with a primary focus on T2DM. It distinguishes diabetes-specific findings from evidence in other populations, compares the information provided by different imaging modalities, and discusses the limitations that remain before EAT assessment can be incorporated into routine cardiometabolic care.