Abstract 4372296: A Site-by-Site Comparison of CT Attenuation, Effective Atomic Numbers, and Electron Densities of Focal Pericoronary Adipose Tissue and Its Relationship to Adjacent Coronary Plaques on Contrast Enhanced Spectral CT

Introduction: Inflammation in pericoronary adipose tissues (PCATs) may occur focally at adjacent plaque sites in the coronary arterial system as suggested by abnormal late-phase enhancement on contrast computed tomography (CT). Hypothesis: Embryologically, characteristics of PCATs differ depending on location. Therefore, we performed a site-by-site comparison of characteristic of PCATS using CT attenuation, effective atomic numbers (EANs), and electron densities (EDs) on non-contrast, early-contrast and late-contrast phase on spectral CT. Methods: This is a retrospective analysis of 10 patients (7 male; mean age, 69±12 years) scheduled for pulmonary vein isolation, who underwent spectral CT (7500, Philips) and routine late phase CT contrast acquisition to evaluate left atrial thrombi. From non-contrast and early- and late-contrast data, CT attenuation (CTA; HU), EANs and EDs (% ED relative to water) of PCATs were determined at a site 1) mean of posterior site of proximal right coronary artery (RCA), 2) anterior site of left main coronary arteries (LMCAs), 3) left site of proximal left circumflex artery (LCX), and 4) left site of distal RCA (4 sites/patient). Results: Of 40 sites in 10 patients using early-phase CT, 20 sites had no-plaques (Group 1), 13 sites had only non-calcified plaques (Group 2), 2 sites had only calcified plaques (Group 3), and 5 sites had mixed plaques (Group 4). Tables revealed CTA, EANs, and EDs of Group 1-4 in each site on non-contrast, and early-phase and late-phase contrast CT. Conclusion: Characteristics of PCATs may differ at each site. By considering these facts, we may predict the future occurrence of adjacent coronary arterial plaques related to PCAT inflammation using spectral CT.