Patient-Level Pericoronary Adipose Tissue Mean Attenuation: Associations with Plaque Characteristics

Pericoronary adipose tissue attenuation (PCAT_a), observed from coronary computed tomography angiography (CCTA), is emerging as an inflammation marker. This study evaluated the relationship between PCAT_a and plaque characteristics, including plaque type, burden, and coronary calcification. An observational study was conducted on 466 patients with suspected chronic coronary syndrome who underwent clinically indicated CCTA. PCAT_a was measured along the proximal 40 mm of the coronary arteries and averaged to represent the patient's level. Plaque type was assessed, compositional plaque volumes were measured, and plaque burdens were quantified. The coronary calcification scores (CCSs) were categorized into groups. Statistical methods included t-tests, ANOVA, and multivariate regression analysis. PCAT_a differed significantly between calcified (-81.7 Hounsfield units (HU)) and soft (-77.5 HU) plaques. PCAT_a was positively associated with total plaque burden (β = 3.6) and non-calcified plaque burden (β = 7.0), but negatively correlated with calcified plaque burden (β = -3.5), independent of clinical factors and tube voltage (p < 0.05). The effect of PCAT_a was stronger when plaques of a different composition were absent. No significant differences in PCAT_a were found among different CCS groups. PCAT_a increased for calcified compared to soft plaques. The non-calcified plaque burden was associated with a higher PCAT_a, while the calcified plaque burden was associated with a lower PCAT_a.