超低剂量胸部CT联合钙感知算法评估冠状动脉钙化积分的可行性

Feasibility of coronary artery calcium scoring assessment with ultra-low-dose chest CT combined with a calcium-aware algorithm

目的评估超低剂量胸部CT平扫(ULD-CT)联合钙感知算法对冠状动脉钙化(CAC)检测、量化和风险分类的可行性。方法前瞻性收集2022年4月至10月于浙江省人民医院同时行标准钙化积分CT(CACS-CT)和ULD-CT扫描的患者115例。CACS-CT采用前瞻性心电门控120 kVp序列扫描,重建卷积核为Qr36(CACS-CT_(Qr)组)。ULD-CT采用非心电门控大螺距锡滤过100 kVp(Sn100 kVp)扫描,分别采用标准卷积核Qr36(ULD-CT_(Qr)组)和钙感知卷积核Sa36(ULD-CTSa组)重建两组图像。以CACS-CT的CAC检出结果为参照,计算ULD-CT检测CAC的准确性,并使用kappa评估扫描协议间CAC检测一致性。使用组内相关系数和Bland-Altman图评估扫描协议间CACS量化的一致性,使用加权kappa评估扫描协议间风险分类的一致性。结果CACS-CT_(Qr)组中66.96%(77/115)的患者发现CAC。以CACS-CT_(Qr)组的CAC检出为对照,ULD-CT_(Qr)和ULD-CTSa检测CAC的敏感性分别为96.1%和97.4%,特异性均为94.73%(k=0.902,0.921)。ULD-CT_(Qr)和ULD-CTSa的CACS均低于CACS-CT_(Qr)(3.6、6.2 vs.8.5,P<0.001),但均与CACS-CT_(Qr)有强相关性(r=0.983,P<0.001)。ULD-CTSa与CACS-CT_(Qr)间CACS的平均差值(12.33)更小,一致性更好(ICC=0.992)。ULD-CTSa与CACS-CT_(Qr)风险分类的一致性(加权k=0.936)相对较高,重新分类率6.08%(7/115)较低。ULD-CT的有效辐射剂量比CACS-CT减少了约77.22%。结论非心电门控ULD-CT联合钙感知算法评估CACS具有可行性。

Objective To evaluate the feasibility of coronary artery calcium(CAC)detection,quantification and risk classification using ultra-low-dose chest CT(ULD-CT)combined with a calcium-aware algorithm.Methods A total of 115 patients were prospectively enrolled from April to October 2022 at Zhejiang Provincial People′s Hospital,who underwent a standard calcium scoring CT(CACS-CT)scan followed by an additional ULD-CT scan.CACS-CT adopted a prospective ECG-triggered sequence scan with a tube voltage of 120 kVp,and the reconstruction algorithm with Qr36(group CACS-CT_(Qr)).ULD-CT adopted non-ECG-triggered high-pitch scan with a tube voltage of Sn 100 kVp,and the standard algorithm Qr36(group ULD-CT_(Qr))and calcium-aware algorithm Sa36(group ULD-CTSa)were respectively used to reconstruct two groups of images.Taking the CAC detection of CACS-CT as a reference,the accuracy of ULD-CT for detecting CAC was calculated,and kappa was used to evaluate the agreement of CAC detection between scanning protocols.The agreement of CACS quantification between scanning protocols was assessed using intraclass correlation coefficients(ICC)and Bland-Altman plots,and the agreement of risk classification between scanning protocols was assessed using weighted kappa.Results The CAC was found in 66.96%(77/115)of patients in CACS-CT_(Qr).Taking the CAC detection in CACS-CT_(Qr) as a reference,the sensitivity of CAC detection in ULD-CT_(Qr) and ULD-CTSa was 96.1%and 97.4%,respectively,and the specificity was 94.73%(k=0.902,0.921).The CACS for ULD-CT_(Qr) and ULD-CTSa was lower than that for CACS-CT_(Qr)(3.6,6.2 vs.8.5;P<0.001),but strongly correlated with CACS for CACS-CT_(Qr)(r=0.983,P<0.001).The mean difference in CACS for ULD-CTSa and CACS-CT_(Qr) was smaller(12.33),and the agreement was better(ICC=0.992).The agreement of risk classifications between ULD-CTSa and CACS-CT_(Qr) was relatively high(weighted k=0.936),and the reclassification rate(6.08%)was relatively low.The effective radiation dose for ULD-CT was reduced by approximately 77.22%compared with that for CACS-CT.Conclusions It is feasible to evaluate CACS using Non-ECG-triggered ULD-CT combined with a calcium-aware algorithm.