Abstract 18610: Focal Pericoronary Adipose Tissue Evaluated by Electron Density Numbers on Non-Contrast Spectral Computed Tomography Was Associated With Coronary Arterial Plaques: A Site-by-Site Analysis

Abstract

Introduction: Inflammation in pericoronary adipose tissue (PCAT) around the coronary arterial wall causes coronary arterial sclerosis. Many studies evaluated the relationship between total PCAT volume and coronary arterial sclerosis on a patient-by-patient basis. Hypothesis: Inflammation in PCAT may occur focally in coronary arterial system to which coronary arterial plaques localize. Using novel spectral CT, based on electron density number (EDN) as a new parameter, the focal characteristics of PCAT were evaluated. Methods: 17 patients (10 males, mean age 70 years) underwent cardiac spectral CT (7500, Philips, Tokyo, Japan). From non-contrast data, EDNs of PCAT were determined at a 1) right side site and 2) left anterior side site of a proximal portion of right coronary arteries (RCA), 3) anterior side site of the left main coronary arteries, 4) left side site of a proximal portion of the left circumflex artery, and left side site of a distal portion of the RCA (five sites each patient). We also evaluated coronary arterial plaques on enhanced CT images at five corresponding sites for which EDNs were determined. Results: For a total of 85 sites among 17 patients using enhanced CT, 31 sites had no plaques (group 1), 14 sites had only non-calcified plaques (group 2), 20 sites had only calcified plaques (group 3), 16 sites had mixed plaques (group 4), and four sites had stent implantations (group 5). The mean of EDNS (%EDW) for 81 sites, excluding four sites with a stent implantation, were 93.5, 93.3, 93.2, and 93.8 in groups 1-4, respectively (P=NS). For a total of 81 sites, excluding four implantation sites, we evaluated the relationship between age and EDNs in groups 1-4. Positive correlations were observed in group 1 (R= 0.40), and 3 (R= 0.40), however negative correlation was observed in group 2 (R= -0.22) and 3 (R= -0.22) between age and EDNs. No significant differences in EDNs were noted between males and females (P=NS). Conclusions: This is the first study in which focal PCAT was evaluated by EDNs and the relationship to coronary arterial plaques determined by site-by-site analysis. This new CT parameter may evaluate the status of PCAT and be a predictor of the future occurrence of coronary arterial plaques, which are related to PCAT inflammation even on non-contrast CT alone.