Imaging of the Pericoronary Adipose Tissue (PCAT) Using Cardiac Computed Tomography

Abstract

Modern coronary computed tomography angiography (CTA) is the gold standard to visualize the epicardial adipose tissue (EAT) and pericoronary adipose tissue (PCAT). The EAT is a metabolic active fat depot enclosed by the visceral pericardium and surrounds the coronary arteries. In disease states with increased EAT volume and dysfunctional adipocytes, EAT secretes an increased amount of adipocytokines and the resulting imbalance of proinflammatory and anti-inflammatory mediators potentially causes atherogenic effects on the coronary vessel wall in a paracrine way ("outside-to-inside" signaling). These EAT-induced atherogenic effects are reported to increase the risk for the development of coronary artery disease, myocardial ischemia, high-risk plaque features, and future major adverse cardiac events. Coronary inflammation plays a key role in the development and progression of coronary artery disease; however, its noninvasive detection remains challenging. In future, this clinical dilemma might be changed by the CTA-derived analysis of the PCAT. On the basis of the concept of an "inside-to-outside" signaling between the inflamed coronary vessel wall and the surrounding PCAT recent evidence demonstrates that PCAT computed tomography attenuation especially around the right coronary artery derived from routine CTA is a promising imaging biomarker and "sensor" to noninvasively detect coronary inflammation. This review summarizes the biological and technical principles of CTA-derived PCAT analysis and highlights its clinical implications to improve modern cardiovascular prevention strategies.

Added Value of CCTA-Derived Features to Predict MACEs in Stable Patients Undergoing Coronary Computed Tomography

“…As highlighted by the CRISP-CT study [ 12 ] and the SCOT-HEART study [ 25 ], there is a positive correlation between low attenuation plaques, pFAI and cardiovascular events considering all extent of coronary artery disease. Goller et al [ 26 ]. demonstrated that the pFAI was significantly higher around culprit lesions compared to non-culprit lesions in acute coronary syndromes.…”

Relationship between Epicardial Adipose Tissue and High-Risk Coronary Plaque Features in Patients with Suspected Acute Coronary Syndrome

“…Moreover, after adjustment for the BMI, CACS, and stenosis ≥50%, EAT volume was, independently, significant associated with HRP (OR=1.2; p=0.0001) and the optimal threshold which maximized the sensitivity (81.1%) and specificity (91.3%) of EAT volume for prediction of HRP was 107.6 cm3 (p<0.0001). A possible explanation of these results is that EAT, similar to subcutaneous fat, produces high levels of proinflammatory cytokines that act directly on coronary artery wall [12]. Moreover, some studies showed that EAT volume has a positive correlation with total cholesterol, low-density-lipoprotein cholesterol and atherogenic risk factors suggesting that it might be an independent risk element for the formation and evolution of HRP [13,14].…”

High-Risk Coronary Plaque Features: A Narrative Review

“…High-risk plaque features that can be reliably assessed with CCTA include the napkin ring sign, positive remodelling, spotty microcalcifications and low-attenuation plaque [ 19 , 20 ]. CCTA can also be used to image peri-coronary adipose tissue and epicardial adipose tissue, both of which are associated with increased risk of coronary disease and CV events [ 21 ].…”

“…Right coronary artery peri-coronary adipose tissue attenuation is associated with CV risk factors and significant coronary stenoses [ 83 ]. Epicardial adipose tissue secretes adipocytokines, leading to a pro-inflammatory state and progression of atherosclerotic disease [ 21 , 84 , 85 ]. Therefore, the presence of peri-coronary adipose tissue especially around the right coronary artery is suggested as a promising imaging biomarker to allow non-invasive assessment of coronary inflammation.…”