Feasibility of Subtraction Coronary Computed Tomographic Angiography and Influencing Factor Analysis: a Retrospective Study

Objective To investigate the feasibility of subtraction coronary computed tomographic(CT)angiography(SubCCTA)to decline calcium artifacts and improve diagnostic accuracy in the presence of coronary calcification and analyze the factors that influence SubCCTA.Methods A total of 294 patients suspected of having coronary artery diseases underwent coronary computed tomographic angiography(CCTA)and SubCCTA.Coronary stenoses were blindly evaluated by two experienced radiologists,which were compared with invasive coronary angiography(ICA).Multiple statistical indexes were adopted to analyze the value of SubCCTA for the diagnosis of calcium stenoses.Results The diagnosable rate of SubCCTA was 67.2%(n=197),and the non-diagnosable rate was 32.8%(n=97).Using SubCCTA,the false positive rate decreased from 56.5%to 17.4%,and the corresponding diagnostic accuracy was increased from 83.6%to 92.9%.Univariate logistic regression analysis showed that height(OR=1.029,95%CI=1.001–1.058),weight(OR=1.025,95%CI=1.004–1.046),left ventricular size(OR=1.018,95%CI=1.007–1.030),cardiothoracic ratio(OR=39.917,95%CI=1.244–1281.098),the average heart rate(OR=0.866,95%CI=0.836–0.896)and heart rate range(OR=0.882,95%CI=0.853–0.912)might be the factors influencing SubCCTA.Conclusion This study suggested that SubCCTA could help improve diagnostic accuracy in the presence of calcium plaques.Moreover,several factors were discovered for the first time to possibly influence SubCCTA,which will be helpful in improving the subtracted image quality.