Abstract: Objective To obtain pericoronary fat attenuation index(FAI)based on the third-generation dual-source coronary artery CT angiography(CCTA), and to explore the association among FAI, CT high-risk plaque, and degree of coronary artery stenosis. Methods Clinical data of 449 patients who underwent CCTA in our hospital during Jan. 2020 and Jun. 2021 were retrospectively analyzed. According to the existence of CT high-risk plaque, the patients were divided into the high-risk plaque group(n=226)and non-high-risk plaque group(n=223). Perivascular FAI of the right coronary artery was measured and compared between the two groups. The diagnostic values of FAI and FAI plus degree of stenosis for CT high-risk plaques were assessed using receiver operating characteristic(ROC)curve. According to the degree of coronary artery stenosis, the high-risk plaque group was subdivided into three groups: group 1(1%-49%), group 2(50%-99%), and group 3(100%), and the differences in FAI were compared. Results FAI was(-81.54±7.46)HU and(-90.12±7.23)HU in the high-risk plaque group and non-high-risk plaque group, respectively(P<0.001). ROC curve showed that the area under ROC curve(AUC)of FAI and FAI plus degree of stenosis in the diagnosis of CT high-risk plaques were 0.800 and 0.849, respectively; the sensitivity were 79.65% and 80.53%, respectively; the specificity were 74.44% and 79.37%, respectively. The optimal threshold for FAI to diagnose CT high-risk plaques was -86.5 HU. In the high-risk plaque group, the FAI of the three groups were as follows:(-84.76±8.23)HU,(-80.41±6.59)HU, and(-77.07±4.50)HU, respectively(P<0.001). Conclusion FAI is a new imaging marker for the sensitive monitoring of coronary inflammation levels, and higher FAI is associated with greater plaque risk.

Key words: Coronary CT angiography, Pericoronary adipose tissue, Fat attenuation index, High-risk plaque, Degree of coronary artery stenosis