Photon-counting detector CT for low-dose chest scans in the evaluation of coronary artery calcium scoring:a feasibility study

ZHAO Yan'e; JIN Dongsheng; SUN Meirong; CHEN Jiliang; TIAN Di; LUO Song; HU Qiuju; LU Guangming

doi:10.19300/j.2024.L21711

Abstract：Objective This study aims to evaluate the feasibility of low-dose chest CT(LD-CT)using photon-counting detector CT(PCD-CT)for the detection,quantification,and risk stratification of coronary artery calcium.Methods A retrospective analysis was conducted on 63 patients with coronary artery calcium who underwent standard calcium scoring CT(ECG-CT)and LD-CT with PCD-CT,a total of 189 vessels involved.Twenty-nine patients were divided into high heart rate group(heart rate>75 beats/min)and 34 patients into low heart rate group(heart rate<75 beats/min).ECG-CT was performed using a prospective ECG-gated 120 kVp scan,while LD-CT utilized non-ECG-gated high-pitch combined with tin filtration at 100 kVp(Sn100 kVp)settings.The Agatston score was used for quantifying coronary artery calcium.Using ECG-CT as the reference standard,the sensitivity,specificity,and accuracy of LD-CT in detecting coronary artery calcification were calculated at both patient and vessel levels,as well as at high and low heart rates.The correlation and agreement between LD-CT and ECG-CT in assessing AS were analyzed by the Spearman correlation coefficient(r)and Bland-Altman method(bias:95%limits of agreement).The agreement of coronary artery calcification risk stratification was assessed by the Weighted Kappa analysis.The difference in effective radiation doses between LD-CT and ECG-CT was compared using the paired t-test.Results ECG-CT detected coronary artery calcification in 130 vessels across all 63 patients.For all patients,LD-CT showed high accuracy(100%)in detecting coronary artery calcification.A strong correlation(r=0.95～0.99,P<0.05)and consistency(-9.7:-125/105.7)were observed between the Agatston scores obtained from both methods.The bias in the left anterior descending artery(LAD)(0.1:-102.8/102.9)was smaller than the left circumflex artery(LCX)(-11.5:-86.9/63.9)and the right coronary artery(RCA)(-8.1:-81.2/65.1).The bias in the low heart rate group(-3.3:-73.4/66.5)was smaller than in the high heart rate group(-18.3:-175.3/138.6).Strong agreement was found in risk stratification based on Agatston scores(kappa=0.963).The effective radiation dose of LD-CT(0.48±0.9 mSv)was 37%(P<0.001)lower than that of ECG-CT(0.77±0.16 mSv).Conclusion LD-CT using PCD-CT not only demonstrated better accuracy in the detection,quantification,and risk stratification of coronary artery calcium but also significantly reduced effective radiation dose.